Md Jinnat Ferdous
email: j.ferdous@uq.edu.au

Helal Uddin

Rashed Mahmud

Mathew Hennessey

Abdullah Al Sattar

Suman Das Gupta

Justine S Gibson

Robyn Alders

Joerg Henning

Guillaume Fournié

Md Helal Uddin

• Rashed Mahmud

Md Ahasanul Hoque

Mapping of dressed and processed poultry products in Bangladesh: Identifying the food safety risks for policy intervention

Keywords: Food-borne pathogens, Food safety, Live bird market, Poultry, Zoonosis

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Approximately a quarter of all animal proteins consumed by humans in Bangladesh are obtained from poultry [START_REF] Hamid | Status of poultry industry in Bangladesh and the role of private sector for its development[END_REF]. Poultry consumption per capita per year is estimated to be 6.3-8.5 kg (LightCastle 2020; WPSA 2020) and is expected to increase by 17% by 2025 (Statista 2022) . While fish protein (19.7 kg) is still the most consumed animal protein in Bangladesh, exotic broiler chicken meat is the most common poultry type consumed per capita per year (5.5 kg), and small portions attributed to Sonali chicken (1.7 kg), duck (0.4 kg) and other poultry species (0.9 kg) (LightCastle 2020; [START_REF] Hennessey | Intensification of fragility: Poultry production and distribution in Bangladesh and its implications for disease risk[END_REF]. The phenotypic homogeneity of exotic broiler chickens such as Hubbard Classic, Cobb-500, Ross, and Hybro-PN (Tan et al. 2021) has facilitated the global development of standardized and automatized processing plants [START_REF] Owens | Poultry Meat Processing[END_REF] , with this growth being fostered by advances in food science, food microbiology, engineering, and marketing (EFSA/ ECDC 2019). Sonali chickens are a crossbred variety between Rhode Island Red males and Fayoumi females introduced to 1 3 Bangladesh in the 1990s as part of the Department of Livestock Services' (DLS) rural poultry program [START_REF] Howlader | Sonali chicken farming in southern part of Bangladesh[END_REF] and an increasingly common variety to produce [START_REF] Hennessey | Intensification of fragility: Poultry production and distribution in Bangladesh and its implications for disease risk[END_REF]. Most poultry meat in Bangladesh is produced on commercial poultry farms (60%) with the rest occurring on traditional backyard farms (LightCastle 2020). Thus, through the provision of key proteins, micronutrients, and employment, poultry production contributes to Bangladesh achieving multiple Sustainable Development Goals (SDGs)1 (UN 2023).

Despite the highly pathogenic avian influenza H5N1 outbreak in 2007 causing significant disruption to the poultry sector, the broiler and layer industry in Bangladesh have experienced annual growth of 3% and 5%, respectively over recent decades (FAOSTAT 2021;[START_REF] Hamid | Status of poultry industry in Bangladesh and the role of private sector for its development[END_REF]. Consequently, the sector employs almost eight million people in Bangladesh [START_REF] Das | Poultry production profile and expected future projection in Bangladesh[END_REF]USDA 2019). In 2019, the total poultry population (at any one time) in Bangladesh was estimated to be in the region of 400 million birds (Department of Livestock Services (DLS), 2020; [START_REF] Hennessey | Intensification of fragility: Poultry production and distribution in Bangladesh and its implications for disease risk[END_REF], involving around 70,000 commercial chicken grower farms throughout the country. The annual production of broiler birds is estimated to be more than half a billion [START_REF] Hennessey | Intensification of fragility: Poultry production and distribution in Bangladesh and its implications for disease risk[END_REF]). These, along with layer birds, are supported by 16 grandparent farms, 206 parent farms and 198 registered feed mills producing around 5.5 million metric tons of feed annually (WPSA 2020).

Most poultry, including exotic broiler chickens, are supplied to consumers in Bangladesh via live bird markets (LBMs) [START_REF] Moyen | Avian influenza transmission risk along live poultry trading networks in Bangladesh[END_REF] where birds are slaughtered and processed on demand at the point of sale. Bangladesh's first commercial company-owned slaughterhouse became operational in 1998. Development of this sub-sector remained slow over the following decade until the establishment of two additional companies in 2009 and six more thereafter, distributed across different regions of the country. Recently, news outlets have reported that consumer demand for dressed and processed poultry products is increasing due to growing concerns over meat hygiene and safety in LBMs (LightCastle 2020).

However, the configurations of the PDN of dressed poultry and processed poultry products are unknown. Additionally, despite poultry meat being a major source of food-borne pathogens, including Campylobacter spp. and Salmonella spp. (EFSA/ECDC 2019), the assessment of meat quality and safety control procedures and its certification by governmental authorities (such as the Bangladesh Food Safety Authority (BFSA), and Bangladesh Standards and Testing Institution (BSTI)) has not been described. Therefore, we aimed to address this knowledge gap through the following objectives: 1) to map the PDN of dressed poultry and processed poultry products in Bangladesh and 2) to assess quality control procedures and hygiene practices that could impact contamination of poultry products by foodborne pathogens.

Materials and Methods

Data Collection

Poultry slaughtering and processing companies

Through consultations with stakeholders (e.g., representatives from the poultry industry, university, livestock research institute, and DLS office) who are knowledgeable about the poultry production systems in Bangladesh, all companies owning poultry slaughterhouses and/or processing plants in Bangladesh were identified (n = 11). All eleven companies were contacted, and nine agreed to participate in the study. To map the PDN of dressed poultry and processed poultry products, in-depth key informant interviews with company representatives, managers, and directors were conducted from June to September 2020. An interview guide for slaughterhouses (Supplementary Information 1) was developed and covered the following topics: i) sources of poultry, ii) modes of transport, iii) slaughtering and processing practices, iv) quality control and hygiene practices in processing plants and during transportation, and v) distribution of finished poultry products.

For our study, slaughterhouses were defined as "premises, including animal transport facilities, used for the slaughter of animals for human consumption or for animal feeding and approved by the national veterinary services or other competent authorities" [START_REF] Shimshony | Slaughter of animals for human consumption[END_REF]. "Dressed poultry" referred to dressed whole poultry, while "processed poultry products" referred to poultry that have undergone processing such as being cut into specific sizes, shapes, or portions; or marinated with spices. "Contracted farms" referred to farms which were provided with production inputs (dayold chicks, feed, and possibly medicine) by a company and are committed by a written contract to sell their chickens at defined rate to that company at the end of each production cycle. "Credit-based farms" referred to farms which were provided production inputs on credit by feed and chick dealers, who generally facilitated the sale of chickens at the end of the production cycle, from which the credits were reimbursed. In contrast, "independent farms" did not depend on the aforementioned arrangements to obtain production inputs and were free to sell to anyone, but also sell through feed dealers.

Supermarkets

Supermarkets, where dressed poultry and processed poultry products were sold to consumers, were also surveyed. All supermarket outlets in Dhaka and Chattogram, the two 1 3 most populated cities in Bangladesh, were identified through an online search and contacted over email and phone. In Dhaka city, we identified 90 outlets, belonging to ten different supermarket chains. However, only the manager from one company -which operated the majority of outlets in Dhaka-agreed to participate. In Chattogram city, there were three supermarket companies (one with two outlets, two with one outlet each) and four individually owned supermarkets selling dressed or live poultry or both. Here, five supermarket managers agreed to participate (one with two outlets, and four with one outlet each).

An interview guide for supermarkets (Supplementary Information 2) was developed covering the following topics: i) types of poultry sold in supermarkets, ii) sources of poultry, iii) quality control and hygiene practices, iv) types of customers and v) modes of delivery to consumers.

For all interviews, open ended questions were used to reduce interviewer confirmation bias and interviewee social desirability bias [START_REF] Powell | Social desirability bias in polling on same-sex marriage ballot measures[END_REF]. Informed verbal consent was obtained prior to the interview, and interviews were voice recorded where consent allowed. Interviews lasted between 40 to 60 min, and recorded in Bengali, and later transcribed into English by the primary author.

Data Analysis

The study was done using deductive thematic analysis described by [START_REF] Chan | Challenges of diabetes self-management in adults affected by food insecurity in a large urban centre of Ontario, Canada[END_REF]. The first author familiarized herself with the raw data by listening to the interviews and reviewing interview scripts to enlist main ideas. Then she identified the main themes and sub-themes, extracted the data using a separate coding template in Microsoft Word (version 365, 2010) for each poultry company with slaughterhouses and/or processing plants and for each supermarket. After coding, rearranging was done according to thematic framework, and finally mapping and interpretation was done based on the research objectives [START_REF] Pope | Qualitative research in health care[END_REF].

Results

Poultry slaughtering and processing companies

The nine interviewed companies with established slaughterhouses processed around 50,000 birds a day, equating to around 3% of the total broiler produced per day in Bangladesh (Table 1). All nine companies participating in the study have head offices in Dhaka but had slaughterhouses and processing plants distributed across different districts of Bangladesh. Seven companies operated their own commercial poultry farms, with the other two companies only sourcing poultry other than raising them themselves. Around 90% of poultry were supplied to company slaughterhouses from their own commercial farms, credit-based farms, and contracted farms. The remaining 10% came from independent farms and traders, small-scale farms of which poultry production was supported, and sales facilitated by non-governmental organizations (Fig. 1).

Poultry slaughter by the nine companies ranged from 2,000 to 9,000 birds per day. Five companies slaughtered only exotic broiler chickens, two companies slaughtered exotic broiler (90%) and Sonali chickens (10%), while the other two slaughtered multiple chicken types and poultry species including Sonali and indigenous chickens, pigeons, ducks, geese, quails, turkeys, though exotic broiler accounted for the majority (90-95%). 1 3

In all slaughterhouses, exotic broiler chickens were slaughtered and processed using a semi-automatic system. Hanging of birds, slaughtering, evisceration, grading, portion cutting, and packaging were done manually. Weighing, stunning, scalding, head removal, defeathering, neck and hock cutting, and chilling were automatized. For other chicken types and poultry species, slaughtering was entirely manual: "All the slaughtering companies in Bangladesh have semi-automatic processes mainly. The step where we need to cut into different portions, that's when human intervention is needed, but before that human handling is not necessary actually" (Director of slaughtering company 5). At all sites, slaughtering was supervised by a prayer leader of a mosque, known as Imam, employed by the company to ensure compliance with Halal standards [START_REF] Shahdan | Developing control points for halal slaughtering of poultry[END_REF].

Eight companies owned processing plants; seven were located adjacent to the slaughterhouses and one was in a different location to the slaughterhouse. Processing plants used meat from dressed poultry to produce ready-to-fry (e.g., chicken rolls, samosas, nuggets) and ready-to-eat (e.g., chicken sausage) products. Dressed and processed poultry products were then stored in processing plants in a chiller (0-4° C) or freezer room (-18 to -20° C) depending on the product requirements until distributed. Products were then distributed by companies to different sales points via chilled and/or freezer vans, mainly within Dhaka city. The delivery of products from sales points to individual consumers' homes was an option offered by five companies, four of which had contracts with food delivery companies. However, this accounted for less than 10% of the products sold by these companies (Fig. 2).

Hygiene and quality control points

In all slaughterhouses, ante-mortem, and post-mortem examination of randomly selected birds from each batch (i.e., birds from the same farm) were conducted by company employed veterinarians to ensure quality control (Table 2). There was no set requirement for the number and selection of birds to be examined, but instead, this was determined by the veterinarian dependent on whether clinical signs were observed. Seven companies had their own laboratory facilities, one company used an external diagnostic laboratory, and one company currently does not have a laboratory, though had expressed a desire to address this deficit:

"We do not have any laboratory of our own at this moment, but we have taken all the preparation to establish one soon." (Manager of slaughtering company 4)

Equipment was cleaned and then disinfected with bleaching powder (Calcium hypochlorite) in eight slaughterhouses once to twice a day before and/or after business hours. Three slaughterhouses washed the dressed birds with food grade bleaching powder dissolved in water, whereas four companies washed the dressed birds with clean water only. Effluent and water treatment plants were present in eight of the slaughterhouses and processing plants.

Eight of the companies performed microbiological sampling of meat looking for total viable count (TVC) and microorganisms such as Escherichia coli, Salmonella spp., Staphylococcus aureus, Listeria spp., yeasts and fungi. The frequency of testing varied between companies, from weekly to bimonthly, and consisted of ten samples (100 g meat and skin) randomly collected from each batch of birds (Table 3). Water (n = 8), air (n = 3), equipment and personnel hand swabs (n = 7), steam and ice (n = 1) samples were collected and tested once monthly, bi-weekly or weekly for microbiological testing as above, and pH, water hardness, and chlorine, arsenic, and iron levels were tested; though testing varied between companies and sample types. Some companies (n = 4) also conducted these analyses annually using an external laboratory for validation. Antimicrobial residue testing was conducted annually for a limited set of antimicrobial classes by four companies through external laboratories (Table 3).

Two companies also collected samples from their supplying farms twice a year, to test for the presence of antimicrobial residues: "We test meat samples for antimicrobial residues and heavy metals monthly once, but we do not test instruments or personnel hand swab samples. However, if any of the personnel in the slaughterhouse have any cold symptoms, we do regular health checkups of that person" (Director of slaughtering company 9)

Companies reported that their customers -supermarkets, restaurants, and fast-food companies required testing for Escherichia coli, Salmonella spp., and Staphylococcus aureus. None of the companies attempted to detect contamination of meat by Campylobacter spp. Due to the time taken to complete testing (an average of 5 days), products which were contaminated/unsuitable for consumption could not be recalled. No testing was performed in downstream nodes (i.e., company distribution or sales points). However, companies maintained records which could be useful for identifying contaminated batches and the supplying farms. But in practice, contaminated batches were not traced back to their supplying farms. If any sample tested positive, then company officers reported that they would reinforce the hygiene and sanitation of their slaughterhouse.

Supermarkets

It was estimated that supermarkets in Dhaka (48/90) and Chattogram (5/7) sold an average of 4000 kg and 73 kg of dressed poultry meat per day, respectively, equating to less than 1% of the average daily total amount of poultry meat

Slaughtering company

Instrument wash n 1 2 3 4 5 6 7 8 9

Disinfectant/food grade soap 8

Carcass wash

Food grade bleaching powder 3

Clean water only 4

Ante-mortem and post-mortem examination of whole birds 9

Laboratory testing

Meat 8

Water 8

Air 3

Equipment and personnel hand swabs 7

Steam and ice 1

Testing regime

Testing in own/external lab 8

Yearly tests performed in an external reference laboratory for quality assurance 4

Facilities at slaughterhouses

Effluent treatment plant 8

Water treatment plant 8

Blending/Rendering plants 3

a Darker cells represent practicing; white cells represent not practicing. 1 3

produced in Bangladesh (DLS 2020). This is likely to be an underestimation given that there were many smaller, privately-owned supermarkets offering dressed poultry for sale in other cities that were not accounted for here. Further quantification would therefore require additional investigation.

Dhaka

Most dressed poultry sold by supermarkets were procured from live bird markets through middlemen rather than directly from the company run slaughterhouses. Indeed, only one supermarket company collected dressed exotic broiler chickens from an established poultry slaughtering company (Fig. 1):

"As we collect dressed broiler chickens from a reputed poultry slaughtering company, we believe its quality being exactly what we want. They will not provide us defective chickens." (Head of distribution point of the supermarket)

This company, the largest supermarket company in Dhaka, purchased between 3,000-3,500 kg of dressed exotic broiler chickens per day from a poultry company slaughterhouse. Dressed poultry were transported by the poultry company's own cold storage van from the slaughterhouse to the supermarket company's distribution point. Other chicken types (Sonali and indigenous/deshi) and duck, geese, quail, pigeon, and turkey were sourced from middlemen/dealers. These birds were transported live by middlemen/dealers from farms to their own informal, non-registered slaughterhouses. There were four such slaughterhouses located in Dhaka, from where dressed poultry were collected by the supermarket company's own cold storage van and brought to the distribution point. However, some live Sonali and deshi chickens were also brought by middlemen/dealers from farms to the supermarket company's distribution point.

"Mostly people like to buy live ones and take them as it is from the outlet. But sometimes if any customer wants, then we slaughter the birds for them" (Head of distribution point of the supermarket) These live chickens accounted for < 5% of poultry marketed by the company. Dressed and live poultry were distributed separately, the former using a cold storage van, to all companies' outlets in Dhaka (Fig. 1).

Chattogram

Supermarkets in Chattogram mostly collect dressed poultry from local live bird markets or middlemen. These middlemen sold poultry from their own farms, sourced poultry from other farms, and slaughtered them in their own informal, non-registered slaughterhouses. The reason for not sourcing dressed birds from slaughtering companies was stated as financial:

"If we source dressed birds from slaughtering companies, the cost will be higher than collecting from other sources. Customers will not be happy to pay that high price and it will not be possible for us to get profit from the sale." (Head of distribution point of the supermarket) Four out of the five supermarket companies in the study brought both live and dressed birds to their outlets. Only one company was found to offer live deshi, Sonali, and spent hens for sale in their outlets. Though the other companies also brought live birds into their outlets, these birds were generally slaughtered and dressed upon their arrival, except for when an order for live birds had been received. These live birds would be then slaughtered within a day in the presence of the customer. Different chicken types (exotic broiler, Sonali, deshi, spent hens) and duck, quail, pigeon, and turkey were sold in supermarket outlets in Chattogram. Customers were mainly consumers, and hotels, cafeterias, corporate houses, or family programs like weddings, birthday parties, etc. All but one outlet received poultry and their products daily, with the remaining outlet only being supplied after receiving consumers' orders. Four of the supermarket companies offered a home delivery service in Chattogram (Fig. 2).

Hygiene and quality control

Dhaka-Supermarket companies did not subject farms from which they sourced poultry and unregistered slaughter places to controls or regular laboratory diagnostic testing for pathogens, residues, or heavy metals. Moreover, intermediaries/suppliers did not have defined procedures for cleaning and disinfection of their unregistered slaughterhouses and their vehicles. However, the head of distribution for the supermarket chain in Dhaka explained how their staff conduct poultry farm inspections: "We have specific suppliers for poultry who collect poultry from farmers. But our quality control staff visits the farms monthly once/twice to check the farm's condition" (Head of distribution point of the supermarket).

Usually, the dressed and live poultry were examined for bruising, blood spots, and breakages in legs and/or wings (i.e., visual appearance) by the personnel in the central distribution point in Dhaka. Products that appeared damaged or did not pass organoleptic tests were returned to their respective sources or suppliers. Quality control personnel were not veterinarians but lay staff who relied on their experience to assess poultry quality. Distribution outlets also examined products on receipt and if signs of damage or deterioration were observed, then they were returned to the central distribution point. Dressed meat was displayed in outlets in a chiller at 4 0 C for 36 h after which it was discarded. In supermarket outlets, live poultry 1 3

were often kept in glass cages in close proximity to where dressed poultry was kept for sale. Though these cages had ventilation pipes connected to the outside of the shop, live birds were handled by the same staff who handled dressed poultry.

Chattogram-The same practices regarding the source farms' biosecurity, laboratory tests for pathogens or heavy metals or residues, and cleanliness and hygiene conditions of the transport vehicles were also reported for supermarkets. Birds were sometimes selected by outlet employees before slaughtering when they were sourced from and slaughtered in live bird markets. Dressed poultry were washed with water in supermarket outlets (n = 3) or by the middleman (n = 2) in Chattogram. Only three supermarket companies used ice during dressed poultry transportation from source to outlets. One supermarket company required that dressed poultry were brought to the outlet within an hour of slaughtering where staff could inspect the condition of the carcasses to ensure quality control.

The supermarkets mainly depended on visual appearance (colour, texture, and smell) rather than doing any microbiological testing by their own or by the sources, as the sources were mostly middlemen and live bird markets. Only one supermarket conducted post-mortem examinations by its quality control staff if there was suspicion about the health status of the purchased birds. If they found any abnormalities after the post-mortem, they condemned the meat without any laboratory testing. The display shelves were sanitized with chlorhexidine gluconate before dressed meats were displayed. Dressed meat was displayed in a chiller at 4 0 C for varying hours (36-72 h) after which unsold meat was supplied to fish farms (n = 2) or returned to their suppliers (n = 3). Only three supermarkets used ice during transport from the outlet to consumers' houses when there was home delivery.

In outlets where live birds were kept and slaughtered in the presence of customers, the butcher section was cleaned and disinfected with bleaching powder or chlorhexidine gluconate at the start of each day. Equipment and the butchering area were also cleaned and disinfected immediately after slaughter. Waste was stored in bins and collected daily by the city's local government services. All personnel were reported to wear aprons, masks, and gloves.

Discussion

Dressed poultry and processed poultry product production is a growing sector in Bangladesh, fueled by consumer desire for food safety and a perception that these products are safer than traditional poultry. However, we identified several risky practices and varying levels of quality checks and controls among stakeholders -poultry companies, slaughterhouses, and supermarkets -involved in producing dressed and processed poultry, which lead us to question this perception of safety.

Poultry companies owning slaughterhouses

Most companies owning slaughterhouses have their own managed poultry farms, which may facilitate traceability and the enforcement of desirable production standards. However, when poultry are supplied by sources other than their own farms, it may be more difficult for companies to ensure such standards. Concerning, small-to medium scale broiler farms in Bangladesh have been found to have inadequate biosecurity [START_REF] Imam | Association between farm biosecurity practices and antimicrobial usage on commercial chicken farms in Chattogram. Bangladesh[END_REF]. Moreover, in a study assessing antimicrobial use in Bangladeshi poultry farms, 84.7% of farmers were found to use antimicrobials prophylactically and 36.1% of broiler farms were found to have sold chickens without maintaining appropriate antimicrobial withdrawal period [START_REF] Imam | A cross-sectional study of antimicrobial usage on commercial broiler and layer chicken farms in Bangladesh[END_REF]). This high level of antimicrobial usage is concerning, with some authors suggesting that farmers have insufficient knowledge about antimicrobial usage and withdrawal periods [START_REF] Hassan | Knowledge, attitude, and practices on antimicrobial use and antimicrobial resistance among commercial poultry farmers in Bangladesh[END_REF]. Likewise, when poultry are supplied by dealers, the companies cannot control the conditions under which birds are transported to slaughterhouses. Yet, incentives and or motivations are low for middlemen to adopt time-consuming and costly hygienic measures. However, hygienic conditions of poultry transport vehicles belonging big middlemen are relatively better (Personal observation, MA Hoque).

Most high-income countries (HIC) have standards for poultry meat production and processing and these standards are enforced by federal and state governments in these HIC (FoodStandards 2019). However, such standards have not been developed for poultry meat processing companies in Bangladesh. These companies are supposed to follow the World Poultry Science Association (WPSA) standards or other international slaughtering standards (LightCastle 2020). But BSTI is the authority who gives the certificate for quality of dressed and/or processed poultry products. Moreover, International Organisation for Standardization (ISO) have their own agent in Bangladesh who give ISO certificate by inspection of slaughtering and processing plants. Moreover, BFSA with the help of Islamic Foundation also visit the slaughtering and processing plants and give the Halal certificate by sudden visits. And recently the BFSA has got the authority to issue health certificates of products which can be imported abroad.

Bangladesh has legal framework to ensure the quality of food produced by the companies. According to Food Safety Act 2013, if anyone sells/stores/produces sick or dead birds, the person will be punished with one to three years of jail time (lowest 1 year) or 0.3 -0.6 million BDT fine payments. There is a separate court, called as Food Court, for the enforcement of Food Safety Act 2013. The judicial power of the court is either in the hand of judicial magistrate or metropolitan magistrate. On the other hand, if there is any offense regarding slaughter (such as poor 1 3 slaughtering environment, sick or diseased slaughter personnel, poor waste management etc.), that falls under Slaughter Act 2011. The punishment for breaching the Slaughter Act 2011 is, one-year jailtime or 5000 to 25,000 BDT fine payments or both. A veterinarian (appointed by the Directorate General -Livestock) will punish them under Mobile Court Act 2009. Thus, it is therefore highly recommended that the WPSA Bangladesh Branch, DLS, BSTI and BFSA establish guidelines for the slaughtering and processing of poultry, including setting up policies for monitoring adherence and the enforcement of these guidelines.

Laboratory diagnostic test protocols are not harmonized across the companies in Bangladesh. While most companies regularly tested their products for a range of microorganisms, this did not include Campylobacter spp. In contrast, HIC such as Australia and New Zealand, follow the Primary Production and Processing (PPP) Standard for poultry meat, aiming to lower the prevalence of Campylobacter and Salmonella as these are the two most common bacteria present in raw poultry meat causing illness in humans (EFSA/ECDC 2019; FoodStandards 2019). Therefore, screening for Campylobacter should be included in the regular laboratory testing protocols of poultry processing companies in Bangladesh. The One Health Poultry Hub Bangladesh has optimized the standard operating procedure (SOP) for Campylobacter testing in Bangladesh, which has been implemented in laboratories of the Poultry Research & Training Center (PRTC), CVASU and Bangladesh Livestock Research Institute (BLRI). These SOPs should be adopted also in poultry processing companies' laboratories in Bangladesh.

All companies should also test their products for antimicrobial residues and heavy metals. At present, test results are not generated rapidly enough to recall contaminated products. More advanced molecular techniques, such as High-Performance Liquid Chromatography (HPLC) or Enzyme-Linked Immunosorbent Assay (ELISA), should be considered for antimicrobial residue and heavy metal testing to reduce the time between sampling and the generation of test results [START_REF] Hoelzer | Emerging needs and opportunities in foodborne disease detection and prevention: From tools to people[END_REF]. Companies should also not just focus on their slaughterhouse's hygiene but also trace back flocks with elevated antimicrobial residues and heavy metal levels. This would allow to reduce the application of antimicrobials on poultry farms and to reduce exposure of birds to heavy metals, and thereby mitigate the prevalence of health hazards at the production stage.

The companies did not use data on the occurrence of health hazards to identify temporal trends. Yet, this data could inform risk assessments and the implementation of risk mitigation interventions along the networks. Companies should also implement disease surveillance activities on the farms supplying them, especially if they consider exporting poultry meat in the future.

Supermarkets

As supermarket companies were mainly supplied through LBMs and middlemen, the actual origins of the birds they were supplied with were generally unknown, and they were unable to monitor and control farm biosecurity standards, antimicrobial usage, and the hygienic and sanitary conditions under which poultry were transported, marketed, and slaughtered. Hygiene standards are usually low in LBMs [START_REF] Chowdhury | Association of biosecurity and hygiene practices with environmental contamination with 1 3 influenza a viruses in live bird markets. Bangladesh[END_REF], with the same bucket of water being used to wash multiple bird carcasses, posing a risk of bacterial cross contamination. Salmonella contamination in dressed poultry and poultry products has been commonly reported in low-middle income countries (LMIC) [START_REF] Khan | Prevalence and serotypes of Salmonella spp. on chickens sold at retail outlets in Trinidad[END_REF][START_REF] Mpundu | Evaluation of bacterial contamination in dressed chickens in Lusaka Abattoirs[END_REF]. For instance, in Trinidad, [START_REF] Khan | Prevalence and serotypes of Salmonella spp. on chickens sold at retail outlets in Trinidad[END_REF] detected Salmonella spp. in chicken carcasses in 20.5% and 8.3% of retail shops and supermarkets, respectively. E. coli and Salmonella were detected in 70% and 2.5% of dressed chickens in retail outlets in Zambia, respectively; with higher levels of contamination in washed carcasses compared to pre-washed carcasses [START_REF] Mpundu | Evaluation of bacterial contamination in dressed chickens in Lusaka Abattoirs[END_REF]. Campylobacter spp. were isolated from 54-75% broiler meat samples from LBMs of several districts of Bangladesh [START_REF] Kabir | Isolation, identification and antimicrobial resistance patterns of Campylobacter species from broiler meat sold at KR Market of Bangladesh Agricultural University Campus, Mymensingh[END_REF]Md 2018;[START_REF] Neogi | Risk of multi-drug resistant Campylobacter spp. and residual antimicrobials at poultry farms and live bird markets in Bangladesh[END_REF]). (Uddin et al. 2019) detected Salmonella and E. coli in dressed poultry meat from supermarkets in Dhaka and suggested that the possible cause of bacterial contamination was unhygienic processing and handling of poultry and poultry products.

However, supermarket managers reported that supermarket outlets strictly enforced the usage of personal protective equipment and frequent cleaning and disinfection. While this may contribute to a reduction of the risk of cross-contamination [START_REF] Luber | Cross-contamination versus undercooking of poultry meat or eggs-which risks need to be managed first?[END_REF][START_REF] Banna | Factors associated with food safety knowledge and practices among meat handlers in Bangladesh: a cross-sectional study[END_REF], and attempts were made to minimize contact between poultry products and live poultry -with live poultry being confined in glass cages with a separate line of ventilation -the such risk of crosscontamination remains, as both bird products and live birds are kept near each other on the same floor and are handled by the same people [START_REF] De Perio | Campylobacter infection in poultry-processing workers, Virginia, USA, 2008-2011[END_REF][START_REF] Rahman | Evaluation of potential risk of transmission of avian influenza A viruses at live bird markets in response to unusual crow die-offs in Bangladesh[END_REF].

There was no legislation about the recruitment of veterinarians by supermarket companies. Thus, supermarket companies don't have veterinarians in their teams, who should oversee the inspection and condemnation of dressed poultry unfit for human consumption. For instance, Australia and New Zealand's laws state the requirement for appointing a Food Safety Supervisor, and that the staff in charge of handling food products should be trained in food safety (Food-Safety 2016).While we could not assess whether supermarket staff have received any kind of food safety training, we therefore recommend the completion of a Food Handler Course as a requirement for all supermarket staff upon their recruitment, and the harmonization of standard operating 1 3 procedures related to the transport, handling, and processing of poultry.

There is a general belief among the urban consumers that dressed poultry would be safer to consume than the traditional poultry sold through LBMs in Bangladesh [START_REF] Islam | Marketing of live poultry in northwest of Dhaka city-A value chain analysis[END_REF][START_REF] Khairunnesa | Evaluation of existing poultry processing and marketing in the wet market of Gazipur city in Bangladesh[END_REF][START_REF] Lightcastle | Poultry sector study Bangladesh[END_REF]. But this study showed that the dressed poultry production and distribution channels overlapped with traditional networks via LBMs. Thus, the consumer's confidence that dressed poultry sold in supermarkets were at lower risk than poultry sold in LBMs was somewhat wrong and may increase the risk of food-borne disease from these supermarket products. Thus, as mentioned above, there is a need to enforce the present food safety legislation in Bangladesh, while awareness campaigns aimed at consumers should emphasize the necessity of proper cooking of dressed poultry and poultry products to prevent food-borne diseases (USDA 2016).

Conclusion

This study described the PDN of dressed poultry and processed poultry products for the first time in Bangladesh. The perceptions of these commodities being safer than birds sold in LBMs may be misleading given interconnections across PDNs. The lack of legislation, and its enforcement, should be addressed by regulatory authorities. The implementation of traceability schemes and the standardization of SOPs related to quality control, slaughtering and processing of poultry should be a requirement for all slaughtering and supermarket companies.

Research limitations

While there were more than 90 supermarket outlets in Dhaka, we were only able to recruit the one supermarket company which operated more than 50 outlets (out of these > 90) in Dhaka. However, this supermarket company is the largest in the country. Besides, this study was conducted while movement restrictions related to COVID-19 were enforced, thus we could not conduct face-to-face interviews, nor collect data through observations. Likewise, the interviewers were unable to visit the slaughterhouses and processing plants, and relied on interviewees' responses, which increased the likelihood of desirability bias.

Fig. 1

 1 Fig. 1 Production and Distribution Networks (PDN) of dressed poultry and processed poultry products in Bangladesh. The size of the arrows indicates the magnitude of poultry numbers in the part of the chain

Fig. 2

 2 Fig.2Types of consumer end points for dressed poultry and processed poultry products in Bangladesh

Table 1

 1 Participant company features and their source of poultry

	Source of poultry

Table 2

 2 Food safety measures practiced in nine slaughtering companies

Table 3

 3

	Microbiological testing done by slaughtering companies		Number of companies performing the test
	(N = 9; one company did not	Test for	Meat	Water	Air	Instruments and per-	Steam and ice
	perform any testing) on a					sonnel hand swab
	regular basis	Escherichia coli	8	6	1	6	1
		Salmonella spp.	8	6	1	6	1
		Staphylococcus aureus	5	3	1	3	1
		Listeria spp.	2	1	1	1	1
		Coliform	6	4	1	3	1
		Yeast/mold	3	1	2	2
		Total viable count (TVC)	8	7	2	7	1
		Antimicrobial residues	4
		Heavy metal	1	3			1
		pH		1

Sustainable development goals: 1 (no poverty),

(zero hunger), and 12 (responsible consumption and production).

Acknowledgements

The authors express gratitude to the study participants from the companies for their time.

Data availability Not applicable.

Code availability Not applicable.

Declarations

Supplementary Information

The online version contains supplementary material available at https:// doi. org/ 10. 1007/ s11259-023-10153-7.

Authors' contributions Conceptualization: Md Ahasanul Hoque; Methodology, Formal Analysis and investigation: Jinnat Ferdous, Md Helal Uddin, Rashed Mahmud, Md Ahasanul Hoque; Writing -original draft preparation: Jinnat Ferdous; Writing -review and editing: Jinnat Ferdous, Matthew Hennessey, Robyn Alders, Justine S. Gibson, Suman Das Gupta, Abdullah Al Sattar, Joerg Henning, Guillaume Fournié, Md. Ahasanul Hoque; Funding acquisition and supervision: Md. Ahasanul Hoque.

Funding Open Access funding enabled and organized by CAUL and its Member Institutions. This work was supported by the UKRI GCRF One Health Poultry Hub [Grant No. BB/S011269/1], one of twelve interdisciplinary research hubs funded under the UK government's Grand Challenge Research Fund Interdisciplinary Research Hub initiative.

Competing interests

The authors declare no competing interests.

Ethics approval

The study was approved by the Ethical Committee of Chattogram Veterinary and Animal Sciences University (CVASU), Bangladesh (Approval No. CVASU/Dir (R&E) EC/2020/165 (2)).

Consent to participate

Verbal consent from the authority of each participating company was taken before the interview.

Consent for publication

We give our consent for the publication of the submitted manuscript.

Conflict of interest

The authors declare no competing interests.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/.

3

Tan C, Selamat J, Jambari NN, Sukor R, Murugesu S, Khatib A ( 2021


Mohammed El

Fallaki Idrissi

Francis Praud
email: francis.praud@ensam.eu

Francisco Chinesta
email: francisco.chinesta@ensam.eu

Fodil Meraghni
email: etfodil.meraghni@ensam.eu

PGD non-intrusive pour la simulation multiparamétrique en temps réel du comportement non-linéaire des composites à renforts tissés intégrant les paramètres microstructuraux Non-intrusive PGD towards real-time multiparametric simulation of nonlinear response for woven composite involving microstructural parameters

Keywords: Composites tissés, Matrice thermoplastique, Modélisation multi-échelle, Comportement non-linéaire, Solution multi-paramétrique, PGD non-intrusive. Réponse en temps réel Woven composites, Thermoplastic matrix, Multi-scale modelling, Nonlinear behaviour, Multiparametric solution, Non-intrusive PGD, Real-time response 1

La modélisation multi-échelle non-linéaire par éléments finis des composites reste aujourd'hui un défi dans des applications industrielles. En effet, son utilisation nécessite une puissance de calcul élevée et donc souvent couteuse en temps, ce qui constitue un verrou majeur rendant impossible la prise de décision en temps réel. C'est pourquoi, la construction de modèles paramétriques est un outil primordial pour pouvoir analyser et optimiser les structures composites. À cette fin, une approche basée sur la PGD non-intrusive est proposée afin d'offrir une solution multi-paramétrique capable d'évaluer quasi-instantanément la réponse macroscopique non-linéaire des composites tissés en fonction de certains paramètres de microstructure. La solution paramétrique est développée pour un matériau composite à renfort tissé (sergé 2,2) et à matrice polyamide 66 pour des séquences d'empilement symétriques et équilibrées de

Cette solution permet d'analyser le comportement macroscopique du composite non linéaire lors de divers types de sollicitations, notamment monotones, charge-décharge et en fluage-recouvrance. Elle prend en considération à la fois le caractère viscoélastique-viscoplastique de la matrice et les dommages subis par les torons.

Introduction

Malgré leur coût généralement élevé, les composites s'avèrent être aujourd'hui une alternative indispensable aux matériaux classiques. Ils sont couramment utilisés dans diverses applications industrielles pour répondre aux exigences de haute résistance et de légèreté, notamment dans l'industrie de transport. Cette demande augmente avec les tendances croissantes en matière de durabilité des véhicules électriques et à hydrogène, qui visent à réduire l'impact des émissions de CO 2 sur l'environnement. En outre, grâce aux procédés de fabrication avancés, la conception des composites devient de plus en plus flexible. De ce fait, il est possible de fabriquer des composites stratifiés sur mesure avec des paramètres optimaux de microstructure afin d'obtenir les performances mécaniques souhaitées. Dans ce contexte, il est essentiel de disposer d'un modèle numérique paramétrique reliant les différents paramètres du composite avec sa réponse mécanique macroscopique. À cette fin, une méthode basée sur la PGD (Proper Order Generalized Decomposition) non-intrusive [START_REF] Chinesta | A short review on model order reduction based on proper generalized decomposition[END_REF][START_REF] Sancarlos | PGD-based advanced nonlinear multiparametric regressions for constructing metamodels at the scarce-data limit[END_REF][START_REF] Borzacchiello | Non-intrusive sparse subspace learning for parametrized problems[END_REF][START_REF] Pasquale | A parametric metamodel of the vehicle frontal structure accounting for material properties and strain-rate effect : application to full frontal rigid barrier crash test[END_REF] est adoptée ici pour fournir des solutions avec une dépendance paramétrique explicite. Ce type d'approche a récemment été utilisé [START_REF] Idrissi | Multiparametric modeling of composite materials based on non-intrusive PGD informed by multiscale analyses : Application for real-time stiffness prediction of woven composites[END_REF] pour construire une solution multi-paramétrique capable d'évaluer quasi-instantanément les propriétés macroscopiques élastiques des composites à renforts tissés en fonction de plusieurs paramètres microstructuraux (architecture, paramètres géométriques, paramètres matériaux, ...).

Dans ce travail, cette approche est étendue au comportement non-linéaire des composites tissés. Dans ce cas, des essais virtuels sont préalablement calculés pour divers paramètres microstructuraux lors de la phase Offline à l'aide d'un modèle multi-échelle non-linéaire intégrant l'endommagement dans les torons ainsi que la rhéologie complexe de la matrice [START_REF] Chatzigeorgiou | Multiscale Modeling Approaches for Composites[END_REF][START_REF] Praud | Fully integrated multi-scale modelling of damage and time-dependency in thermoplastic-based woven composites[END_REF][START_REF] Praud | Multi-scale modelling of thermoplastic-based woven composites, cyclic and time-dependent behaviour[END_REF][START_REF] Praud | Phenomenological multi-mechanisms constitutive modelling for thermoplastic polymers, implicit implementation and experimental validation[END_REF][START_REF] Praud | Hybrid micromechanical-phenomenological modelling of anisotropic damage and anelasticity induced by micro-cracks in unidirectional composites[END_REF]. La solution multi-paramétrique obtenue à l'issue de la phase Online permet de visualiser en temps réel l'influence de la microstructure sur le comportement macroscopique non-linéaire du composite lors de sollicitations monotones, charge-décharge et en fluage-recouvrance. La solution développée dans ce travail a été testée et validée sur un composite à matrice polyamide 66 et à renfort en fibres de verre de type sergé 2/2 sous trois configurations de chargement et pour deux orientations différentes. Par ailleurs, cette solution multi-paramétrique peut être également utilisée à la volée pour calibrer des modèles phénoménologiques ou pour alimenter des modèles basés sur des réseaux de neurones en produisant une base d'essai virtuels.

2.

Paramètres du problème :

Les composites tissés se caractérisent par un comportement anisotrope complexe résultant de l'arrangement géométrique de leur microstructure ainsi que des propriétés de leurs constituants, à savoir le renfort tissé et la matrice. Afin de développer une solution paramétrique s'appliquant pour divers types de sollicitations, les trajets de chargement suivant sont considérés dans la présente étude :

-Essai de traction monotone : Le matériau est soumis à une traction monotone suivant l'axe ì 𝑥 selon deux orientations différentes (𝜃 = 0 • et 𝜃 = 45 • ). Lors de cet essai, une déformation macroscopique 𝜀 𝑥 𝑥 = 0.02 est appliqué pour 𝜃 = 0 • , tandis qu'une déformation de 𝜀 𝑥 𝑥 = 0.035 est appliquée pour 𝜃 = 45 • . Trois vitesses de déformation différentes sont considérées pour chacune des orientations ( 𝜀 𝑥 𝑥 = 2 × 10 -4 s -1 , 𝜀 𝑥 𝑥 = 2 × 10 -3 s -1 et 𝜀 𝑥 𝑥 = 2 × 10 -2 s -1 , comme le montre la Figure 3a.

-Essai de charge-décharge : La représentation schématique de cette simulation est illustrée sur la Figure 3b où le matériau est soumis à un signal triangulaire cyclique de contrainte (charge-décharge) sous des amplitudes progressivement croissantes correspondant à 10 %, 30 %, 50 %, 70 % et 100 % de la contrainte maximale 𝜎 max , successivement. Cette dernière dépend de l'orientation 𝜃 (pour 𝜃 = 0 • , 𝜎 max =350 MPa et pour 𝜃 = 45 • , 𝜎 max =90 MPa). Il convient de noter que le même taux de contrainte est maintenu pendant cet essai qui est égal à 35 MPa.s -1 pour 𝜃 = 0 • et à 9 MPa.s -1 pour 𝜃 = 45 • .

-Essai de fluage-recouvrance : Des tests de fluage-recouvrance sont réalisés sur le matériau en appliquant progressivement trois niveaux de contraintes croissantes : 50 %, 75% et 100 % de la contrainte maximale 𝜎 max (Figure 3c). Cette configuration d'essai met en évidence les effets de fluage causés par le comportement viscoélastique et viscoplastique de la matrice. La première étape de cet essai consiste à charger le matériau en 2.5 secondes à une contrainte équivalente à 50% de 𝜎 max . Cette contrainte est ensuite maintenue pendant 300 secondes avant d'être relâchée en 2.5 secondes. Le composite est alors laissé libre de toute contrainte pendant 300 secondes supplémentaires. Le test se poursuit en répétant les mêmes étapes de chargement en augmentant l'amplitude de la contrainte appliquée sans changer le taux de chargement. Il faut noter que pour 𝜃 = 0 • , 𝜎 max atteint 350 MPa, tandis que pour un angle 𝜃 = 45 • , la contrainte maximale 𝜎 max est de 90 MPa.

Modélisation Multi-échelle :

3.1.

Homogénéisation périodique :

En utilisant cette représentation paramétrique, une cellule unitaire est créée et maillée automatiquement pour chaque ensemble de paramètres microstructuraux 𝒑 dans l'espace de paramètres correspondant (Figure 1b). Cette opération est effectuée de manière automatisée à l'aide d'un script python spécialement développé dans le logiciel TexGen [START_REF] Brown | TexGen[END_REF].

La réponse macroscopique non-linéaire du composite est alors déterminée, pour chaque trajet de chargement prédéfini (voir les Figures 3a, 3b et 3c), en utilisant le concept d'homogénéisation périodique. Comme toutes les approches multi-échelles, l'homogénéisation périodique impliquent une connexion entre les échelles microscopique et macroscopique. Cette liaison est définie en utilisant le théorème de la moyenne [START_REF] Chatzigeorgiou | Multiscale Modeling Approaches for Composites[END_REF] qui permet d'écrire la contrainte et la déformation macroscopique, 𝝈 et 𝜺 comme étant la moyenne volumique de leurs contreparties microscopique sur l'ensemble du domaine de la cellule unitaire 𝔅 :

𝝈(𝑡) = 1 𝑉 ∫ 𝔅 𝝈(𝒙, 𝑡) d𝑉, 𝜺(𝑡) = 1 𝑉 ∫ 𝔅 𝜺(𝒙, 𝑡) d𝑉, (Eq. 1)
où 𝑉 représente le volume du domaine 𝔅. Dans le cas de l'homogénéisation périodique, les relations de transition d'échelle sont complétées par l'hypothèse de périodicité [START_REF] Suquet | Elements of homogenization for inelastic solid mechanics[END_REF], qui permet d'écrire le champ de déplacement 𝒖 à l'intérieur de la cellule unitaire sous la forme suivante :

𝒖(𝒙, 𝑡) = 𝜺(𝑡) • 𝒙 + 𝒖 ′ (𝒙, 𝑡) + 𝒖 0 (𝑡), ∀𝒙 ∈ 𝔅. (Eq. 2)
On remarquera que cette équation est composée d'une partie affine, 𝜺 • 𝒙, d'une fluctuation périodique 𝒖 ′ et d'un éventuel mouvement de corps rigide 𝒖 0 . La périodicité de 𝒖 ′ implique que ce champ prend des valeurs identiques à chaque pair de points opposés 𝒙 + et 𝒙 -se trouvant sur les bords de la cellule unitaire 𝜕𝔅. En combinant cette condition avec (Eq. 2), la condition de périodicité peut se reformuler en fonction de 𝒖, tout en impliquant directement le tenseur de déformation macroscopique 𝜺 :

𝒖(𝒙 + , 𝑡) -𝒖(𝒙 -, 𝑡) = 𝜺(𝑡) • (𝒙 + -𝒙 -), ∀𝒙 + , 𝒙 -∈ 𝜕𝔅, (Eq. 3)
définissant ainsi les conditions aux limites à appliquer sur la cellule unitaire [START_REF] Chatzigeorgiou | Multiscale Modeling Approaches for Composites[END_REF][START_REF] Praud | Fully integrated multi-scale modelling of damage and time-dependency in thermoplastic-based woven composites[END_REF][START_REF] Praud | Multi-scale modelling of thermoplastic-based woven composites, cyclic and time-dependent behaviour[END_REF][START_REF] Li | General unit cells for micromechanical analyses of unidirectional composites[END_REF]. La réponse macroscopique du composite peut alors se déduire en solutionnant par éléments finis le problème de la cellule unitaire avec ces conditions aux limites, tout en considérant les relation de transition entre les échelles macroscopique et microscopique (Eq. 1).

Modèles constitutifs locaux pour la matrice et les torons :

La matrice thermoplastique présente un comportement dissipatif bien connu combinant des propriétés solides et fluides tout en étant sujet à des mécanismes de dégradation. Au sein de la phase matricielle 𝔅 0 de la cellule unitaire 𝔅, ce comportement est décrit à l'aide d'un modèle développé au sein de l'équipe et appelé VEVPD (Viscoplastique-Viscoélastique avec Endommagement) [START_REF] Praud | Phenomenological multi-mechanisms constitutive modelling for thermoplastic polymers, implicit implementation and experimental validation[END_REF]. Les équations constitutives de cette loi intègrent les déformations viscoélastiques et viscoplastiques ainsi que de l'endommagement ductile selon le schéma rhéologique représenté sur la Figure 4a

Ψ = Ψ(𝜺, 𝜺 𝑠 , 𝛾 𝑐 ) ⇒ 𝝈 = 𝜕Ψ 𝜕𝜺 = [C 0 -D(𝛾 𝑐 )] : (𝜺 -𝜺 𝑠 ), ∀𝒙 ∈ (𝔅 1 ∪ 𝔅 2 ) ⊂ 𝔅, (Eq. 5)
cette relation étant complétée par des lois d'évolution des variables internes 𝜺 𝑠 et 𝛾 𝑐 .

(a) Schéma rhéologique de la loi de comportement de la matrice thermoplastique.

(b) Principe de modélisation pour la loi de comportement des torons. De la même manière, on cherche aussi à estimer la déformation macroscopique 𝜺 𝑥 𝑥 en fonction des paramètres 𝒑 lorsque le composite est subit un trajet de chargement de type charge-décharge ou fluage-recouvrance contrôlé en contrainte macroscopique {𝝈 𝑥 𝑥 (𝑡)} (Comme précédemment décrit dans la section 2) :

Décomposition Propre Généralisée non-intrusive (PGD non-intrusive)

𝜺 𝑥 𝑥 ( 𝑝 1 , 𝑝 2 , 𝑝 3 , 𝑝 4 ; {𝝈 𝑥 𝑥 (𝑡)}) = 𝑀 ∑ 𝑖=1 𝑁 =4 𝑗=1 𝐹 𝑖 𝑗 ( 𝑝 𝑗 ; {𝝈 𝑥 𝑥 (𝑡)}).
(Eq. 8)

Résultats

En faisant appel à une stratégie d'échantillonnage parcimonieux adaptatif comprenant 81 points de collocation répartis sur les bords et au centre de l'espace paramétrique, des solutions de haute fidélité ont été obtenues à ces points en utilisant l'approche multiéchelle présentée précédemment afin d'entrainer le modèle PGD non-intrusive. Ensuite, une série de calculs est effectuée sur 34 microstructures générées aléatoirement dans l'espace des paramètres géométriques afin de tester ce modèle. Parmi celles-ci, quatre microstructures {𝑀 1 , 𝑀 2 , 𝑀 3 , 𝑀 4 }, listées dans la Table 1 ont été sélectionnées pour comparer leur réponse macroscopique (courbe contrainte-déformation et courbe déformation-temps) avec les résultats éléments finis lorsque ces échantillons sont soumises à différentes sollicitations telles que de la traction monotone à différents taux de déformation, des cycles de charge-décharge et des essais de fluage-recouvrance. Dans cette étude, la solution paramétrique est obtenue à l'aide de la méthode SSL (Sparse Subspace Learning) [START_REF] Borzacchiello | Non-intrusive sparse subspace learning for parametrized problems[END_REF] qui est basée sur PGD non-intrusive, tout en utilisant une interpolation spline pour déterminer les fonctions unidirectionnelles. Les Figures 5a et 5b illustrent les comparaisons entre les valeurs de la contrainte macroscopique de référence obtenue par la méthode des éléments finis (𝜎 𝑅 𝑥 𝑥 ) et celles de la contrainte macroscopique prédite par la méthode de PGD non-intrusive (𝜎 𝑃 𝑥 𝑥 ) lors de l'essai de traction monotone à trois vitesses de déformation (2 × 10 -4 , 2 × 10 -3 et 2 × 10 -2 s -1 ). Les résultats sont présentés pour deux séquences d'empilement, à savoir [±, 0 • ]s et [±, 45 • ]s. Il est pertinent de mentionner que, dans le but de simplifier la représentation graphique, seules certaines valeurs de contrainte ont été sélectionnées pour chaque essai. Ces points sont uniformément répartis le long du trajet de chargement (Figure 3a) pour les 34 microstructures de test. En observant ces courbes, il est évident que cette méthode est capable de prédire précisément les valeurs de la contrainte lorsque l'un des paramètres microstructuraux varie. Les Figures 5c et 5d comparent la courbe contrainte-déformation de référence (EF) avec la courbe prédite (PGD non-intrusive) de quatre échantillons, mettant également en évidence l'influence de la microstructure et de la vitesse de déformation sur la réponse macroscopique pour

Microstructure 𝑎 1 [mm] 𝑎 2 [mm] h[mm] c[mm] 𝑀 1 2.
[± 0 • ] s et [± 45 • ] s , respectivement.
En utilisant la même représentation graphique que celle présentée précédemment pour l'essai de traction, les Figures 6a et 6b permettent cette fois-ci de comparer respectivement la déformation macroscopique prédite (𝜀 𝑃 𝑥 𝑥 ) avec la déformation de référence (𝜀 𝑅 𝑥 𝑥 ) pour les mêmes microstructures utilisées dans le test, lorsqu'elles sont soumises aux essais de charge-décharge et orientées à des angles de 0

Conclusions

En se basant sur des méthodes de PGD non-intrusive, ce travail vise à développer une solution multi-paramétrique pour simuler le comportement macroscopique d'un composite thermoplastique à renfort tissé de type sergé

Fig. 2 .

 2 Fig. 2. -Schéma représentant les deux orientations prises en compte, à savoir 0 • et 45 • , ainsi que l'axe de chargement.

( a )

 a Essais de traction monotone effectué à trois vitesse de déformation 2×10 -4 , 2×10 -3 et 2 × 10 -2 s -1 . (b) Essai de charge-décharge . (c) Essai de fluage-recouvrance.

Fig. 3 .

 3 Fig. 3. -Trajets de chargement appliqués au composite stratifié pour un empilement symétrique de [± 0 • ] s par rapport à l'axe de chargement ì 𝑥 .

Fig. 4 .

 4 Fig. 4. -Schémas illustratifs des lois de comportement pour la matrice thermoplastique et pour les torons.

Fig. 5 .

 5 Fig. 5. -Résultats de l'essai de traction monotone à trois vitesses de déformation (2 × 10 -4 , 2 × 10 -3 et 2 × 10 -2 ) pour deux séquences d'empilement correspond aux [± 0 • ] s et [± 45 • ] s . (a) et (b) Contrainte macroscopique de référence obtenue par EF (𝜎 𝑅 𝑥 𝑥 ) vs. Contrainte macroscopique prédite par PGD non-intrusive (𝜎 𝑃 𝑥 𝑥 ) calculée à dix endroits uniformément répartis sur le trajet de chargement pour les 34 microstructures de test. (c) et (d) Comparaison de courbe contrainte-déformation (Référence vs. Prédiction) pour les quatre microstructures (𝑀 1 , 𝑀 2 , 𝑀 3 et 𝑀 4 ).

Fig. 6 .

 6 Fig. 6. -Résultats de l'essai de charge-décharge pour deux configurations de stratifiés correspond aux [± 0 • ] s et [± 45 • ] s . (a) et (b) Déformation macroscopique de référence obtenue par EF (𝜀 𝑅 𝑥 𝑥 ) vs. Déformation macroscopique prédite par PGD non-intrusive (𝜀 𝑃 𝑥 𝑥 ) calculée à des endroits uniformément répartis sur le trajet de chargement pour les 34 microstructures de test. (c) et (d) Comparaison de courbe contrainte-déformation (Référence vs. Prédiction) pour les quatre microstructures (𝑀 1 , 𝑀 2 , 𝑀 3 et 𝑀 4 ).

  (a) 𝜀 𝑅 𝑥 𝑥 vs 𝜀 𝑃 𝑥 𝑥 pour le stratifié [± 0 • ] s . (b) 𝜀 𝑅 𝑥 𝑥 vs. 𝜀 𝑃 𝑥 𝑥 pour le stratifié [± 45 • ] s . (c) 𝜎 𝑥 𝑥 vs. 𝜀 𝑥 𝑥 pour le stratifié [± 0 • ] s . (d) 𝜎 𝑥 𝑥 vs. 𝜀 𝑥 𝑥 pour le stratifié [± 45 • ] s . (e) 𝜎 𝑥 𝑥 vs. temps pour le stratifié [± 0 • ] s . (f) 𝜎 𝑥 𝑥 vs. temps pour le stratifié [± 45 • ] s .

Fig. 7 .

 7 Fig. 7. -Résultats de l'essai de fluage-recouvrance pour deux configurations de stratifiés correspond aux [± 0 • ] s et [± 45 • ] s . (a) et (b) Déformation macroscopique de référence obtenue par EF (𝜀 𝑅 𝑥 𝑥 ) vs. Déformation macroscopique prédite par PGD non-intrusive (𝜀 𝑃 𝑥 𝑥 ) calculée à des endroits uniformément répartis sur le trajet de chargement pour les 34 microstructures de test. (c) et (d) Comparaison de courbe contrainte-déformation (Référence vs. Prédiction) pour les quatre microstructures (𝑀 1 , 𝑀 2 , 𝑀 3 et 𝑀 4 ). (e) et (f) Comparaison de courbe déformation-temps (Référence vs. Prédiction) pour les mêmes microstructures.

avec les angles suivants : 𝜃 = 0 • et 𝜃 = 45 • , comme le montre les Figures 2a et 2b. Il convient de rappeler que

  Les renforts tissés classiques sont généralement obtenus à partir d'un entrelacement orthogonal de torons trames et chaînes, eux-mêmes composés de nombreuses fibres orientées selon les directions (1) et (2), respectivement. Plusieurs types d'architectures (équilibrée/déséquilibrée) sont couramment utilisés dans diverses applications industrielles, comme le taffetas, sergé et satin. Ils se distinguent non seulement par leurs différents motifs de tissage, mais aussi par leurs caractéristiques distinctes telles que la stabilité et le drapé. Par conséquent, le comportement mécanique des composites tissés est fortement influencé par leur microstructure. Ainsi, différentes réponses macroscopiques peuvent être obtenues en modifiant la géométrie du renfort, le modèle de tissage ainsi que le comportement de leurs constituants.La présente contribution se concentre sur les composites tissés à renfort sergé 2/2. Sur la base de cette architecture, la Figure1amontre les paramètres prise en compte dans cette étude pour définir la géométrie de cette microstructure, la largeur du toron trame 𝑎 1 ∈ [0.8, 4.5] (mm), la largeur du toron chaîne 𝑎 2 ∈ [0.8, 4.5] (mm), la distance entre deux torons adjacents 𝑐 ∈ [0.3, 0.6] (mm) et l'épaisseur de tissu ℎ ∈ [0.2, 0.6] (mm). Il convient de noter que la distance entre deux torons adjacents 𝑐 est considérée comme étant la même pour les torons trame et chaîne. En outre, les torons ont une épaisseur égale à la moitié de l'épaisseur du tissu ℎ, tandis que 10% de ℎ sont ajoutés pour définir l'épaisseur du domaine de la matrice. Ces paramètres sont regroupés dans un vecteur 𝒑 = {𝑝 1 , 𝑝 2 , 𝑝 3 , 𝑝 4 } T contenant les quantités mentionnées ci-dessus. , dans cette configuration, il n'y a pas de couplage traction-cisaillement ou traction-flexion, de sorte que l'ensemble du stratifié peut être chargé axialement sans générer de cisaillement ou de courbure. L'épaisseur d'une seule couche est d'environ 1.1 × ℎ mm, ce qui donne une épaisseur totale de 4.4 × ℎ mm pour chaque échantillon.

	Matrice
	Toron Trame
	Toron Chaıne
	(a) Paramètres géométriques de la microstructure.	(b) Microstructures générées pour différentes
		valeurs de paramètres.
	Fig. 1. -Paramètres géométriques du sergé 2/2. 𝑎 1 : la largeur du toron trame. 𝑎 2 : largeur du toron chaîne. h : l'épaisseur du tissu. c
	l'écart entre deux torons adjacents.
	En modifiant les caractéristiques géométriques du renfort tissé, des simulations ont été menées sur des éprouvettes de composite stratifié
	chargées axialement en traction le long de la direction ì 𝑥. Des séquences d'empilement symétriques et équilibrées [±𝜃] s sont considérées
	pour les éprouvettes

  . Ce dernier consiste en un ressort soumis à une déformation élastique instantanée, 𝑁 branches viscoélastiques de Kelvin-Voigt, chacune étant soumise à une déformation viscoélastique 𝜺 𝑣 𝑖 , et une branche viscoplastique soumise à une déformation viscoplastique 𝜺 𝑝 s'accompagnant d'un écrouissage 𝑟. Par ailleurs, l'endommagement, considéré ici comme un phénomène isotrope est décrit par la variable d'endommagement 𝐷. Dérivant d'un potentiel d'état, l'expression de la contrainte dans la matrice est donnée par :Ψ = Ψ(𝜺, 𝜺 𝑣 𝑖 , 𝜺 𝑝 , 𝑟, 𝐷) 𝑣 𝑖 -𝜺 𝑝 , ∀𝒙 ∈ 𝔅 0 ⊂ 𝔅, (Eq. 4)cette relation étant complétée par des lois d'évolution des variables internes 𝜺 𝑣 𝑖 , 𝜺 𝑝 , 𝑟 et 𝐷. Ce type de modélisation permet de capturer certains effets bien connus des polymères thermoplastiques tels que la dépendance à la vitesse de sollicitation, le fluage, la relaxation, ainsi que le couplage de ses effets avec l'endommagement.

	⇒	𝝈 =	𝜕Ψ	= (1 -𝐷)C
			𝜕𝜺

𝑒 : 𝜺 -𝑁 ∑ 𝑖=1 𝜺

Dans les torons, représentés par les sous-domaines 𝔅 1 et 𝔅 2 pour les torons de trame et de chaîne, respectivement, la présence d'un renfort continu (fibres longues) fait que le comportement longitudinal apparaît comme étant linéaire élastique jusqu'à rupture brutale. Cependant, le comportement transverse présente une dégradation plus progressive provoquée par la croissance d'un réseau diffus de micro-fissures dans l'inter-fibre. Ce comportement est modélisé ici par la loi de comportement développée par

[START_REF] Praud | Hybrid micromechanical-phenomenological modelling of anisotropic damage and anelasticity induced by micro-cracks in unidirectional composites[END_REF]

à travers une approche hybride phénoménologique/micro-mécanique. La perte de rigidité anisotrope D induite par la micro-fissuration est calculée par un schéma d'homogénéisation par champs moyens en introduisant une densité de micro-fissure 𝛾 𝑐 dans le volume élémentaire représentatif, comme le montre la Figure

4b

. Par ailleurs, l'endommagement dans les torons s'accompagne de déformations permanentes dues à au frottement des micro-fissures, empêchant ces dernières de se refermer. Cet aspect est phénoménologiquement décrit par un tenseur de déformation inélastique noté 𝜺 𝑠 qui s'ajoute à la déformation élastique. Dérivant aussi d'un potentiel d'état, l'expression de la contrainte dans les torons est donnée par :

  La prédiction de la réponse macroscopique des composites tissés dépend d'un processus numérique impliquant des techniques d'homogénéisation, l'utilisation d'un solveur éléments finis, ainsi que la génération de la microstructure et son maillage. Ce coût de calcul élevé que tout ce processus implique est suffisamment important pour entraver son utilisation dans un contexte industriel, et plus particulièrement quand il est nécessaire d'évaluer plusieurs configurations avec différentes valeurs de paramètres. Cela peut rendre le processus de conception et d'optimisation excessivement long. Pour surmonter ces limitations, la présente contribution se propose d'utiliser le concept de PGD non-intrusive pour mettre en oeuvre une approximation multi-paramétrique basée sur des solutions pré-calculées en certains points de l'espace paramétrique[START_REF] Sancarlos | PGD-based advanced nonlinear multiparametric regressions for constructing metamodels at the scarce-data limit[END_REF][START_REF] Chinesta | PGD-based computational vademecum for efficient design, optimization and control[END_REF]. Les méthodes de PGD non-intrusives sont particulièrement pratiques dans ce contexte, car elles n'utilisent que des données qui peuvent être obtenues indépendamment des processus numériques standard, tels que les simulations M désignent le nombre de paramètres et le nombre de modes, respectivement.En se basant sur la représentation séparée des variables (Eq. 6), nous cherchons dans ce travail à approximer la contrainte macroscopique 𝝈 𝑥 𝑥 en fonction des paramètres microstructuraux lorsque le matériau est soumis à une traction monotone pilotée par une déformation macroscopique {𝜺 𝑥 𝑥 (𝑡)}, sous forme séparée comme suit : 𝝈 𝑥 𝑥 ( 𝑝 1 , 𝑝 2 , 𝑝 3 , 𝑝 4 ; {𝜺 𝑥 𝑥 (𝑡)}) =

	où N et 𝑀	𝑁 =4
	∑	𝐹 𝑖 𝑗 ( 𝑝 𝑗 ; {𝜺 𝑥 𝑥 (𝑡)}).	(Eq. 7)
	𝑖=1	𝑗=1
	𝑀	𝑁
	∑		𝐹 𝑖 𝑗 ( 𝑝 𝑗 ),	(Eq. 6)
	𝑖=1	𝑗=1

par éléments finis. Cela contraste avec les méthodes conventionnelles basées sur la PGD classique

[START_REF] Ammar | A new family of solvers for some classes of multidimensional partial differential equations encountered in kinetic theory modeling of complex fluids[END_REF]

qui nécessitent des processus numériques ou des solveurs spécifiquement adaptés. L'idée principale de cette technique est d'approximer la solution 𝑠( 𝑝 1 , ..., 𝑝 𝑁 ) en une somme finie de produits de fonctions unidimensionnelles 𝐹 𝑖 𝑗 ( 𝑝 𝑗 ) :

𝑠( 𝑝 1 , ..., 𝑝 𝑁 ) ≈

  • et 45 • par rapport à l'axe de chargement ì 𝑥. Encore une fois, ces Figures démontrent la capacité de cette méthode à reproduire la réponse macroscopique pour d'autres microstructures qui n'ont pas été utilisées lors de la phase d'entraînement. Cette capacité est clairement visible dans les Figures 6c et 6d, qui présentent les courbes de contrainte-déformation macroscopique. Ces courbes mettent en évidence l'influence de la microstructure sur la réponse macroscopique, y compris la dégradation du matériau. La déformation macroscopique obtenue par EF (𝜀 𝑅 𝑥 𝑥 ) vs celle calculée par PGD non-intrusive (𝜀 𝑃 𝑥 𝑥 ) est présentée dans les Figures 7c et 7d pour les essais de fluage-recouvrance. Là aussi, ces essais sont simulés sur des éprouvettes avec des séquences d'empilement de [±, 0 • ]s et [±, 45 • ]s. Une comparaison entre les courbes macroscopiques de contrainte-déformation des microstructures {𝑀 1 , 𝑀 2 , 𝑀 3 , 𝑀 4 } est également établie dans les Figures 7a et 7b. Les Figures 7e et 7f illustrent les réponses en déformation obtenues à partir de la solution paramétrique et des résultats de référence pour différentes valeurs de paramètres géométriques. Ces essais mettent en évidence de manière significative la nature visqueuse du composite, qui est induite par la loi de comportement de la matrice PA66.

  2/2 et matrice polyamide 66. L'objectif est de construire, dans une phase Offline, une solution globale décrivant le comportement viscoplastique-viscoplastique avec endommagement du composite tissé lorsque ce dernier est soumis à des trajets de chargement prédéfinie (sollicitations monotones, fluage-recouvrance et charge-décharge), pour deux configurations de stratifiés[± 0 • ] s et [± 45 • ] s .Cette solution permettra par la suite, dans une phase Online, d'accéder à la réponse macroscopique du composite pour tout type de microstructure possible sans avoir recours à la génération de la microstructure ou au calcul élément finis. Ce type d'approximation paramétrique est numériquement plus attractive pour enrichir des modèles basés sur les réseaux de neurones ou pour calibrer des modèles phénoménologiques de composites en fournissant une base de données d'essai virtuels. En outre, sur la base de cette approximation, l'optimisation des structures composites (identification des paramètres optimaux permettant d'atteindre les performances mécaniques souhaitées) devient plus facile en visualisant, en temps-réel, l'impact de la microstructure sur la réponse macroscopique du composite. (a) 𝜀 𝑅 𝑥 𝑥 vs. 𝜀 𝑃 𝑥 𝑥 pour le stratifié [± 0 • ] s . (b) 𝜀 𝑅 𝑥 𝑥 vs. 𝜀 𝑃 𝑥 𝑥 pour le stratifié [± 45 • ] s . (c) 𝜎 𝑥 𝑥 vs. 𝜀 𝑥 𝑥 pour le stratifié [± 0 • ] s . (d) 𝜎 𝑥 𝑥 vs. 𝜀 𝑥 𝑥 pour le stratifié [± 45 • ] s .

Remerciements

Les auteurs tiennent à remercier la chaire ESI et le Centre HPC Arts et Métiers Cassiopee pour leur soutien dans la conduite des recherches présentées dans ce travail.


Pierre Benoit

Laure Mamy

Yoce Aprianto

Dominique Patureau

Eric Latrille

Virginie Rossard

Rémi Servien

Fabienne Bessac

Sophie Hoyau

Christelle Margoum

BASF Carola Schriever

Bernhard Gottesbueren

Bas Buddendorf

Future challenges for using in silico molecular typology for risk assessment of pesticides metabolites -the example of Typol

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

In Silico Approach applied on pesticide TPs 5 • Computational tools and softwares to predict degradation pathways The pathway prediction system provides different relative reasoning models to predict likely biotransformation pathways and products Examples :

• EnviPath* (https://envipath.org)

• Eawag_BBD* (http://eawag-bbd.ethz.ch/predict/)

• PathPred* (https://www.genome.jp/tools/pathpred/)

• Chemical Transformation Simulator (https://qed.epa.gov/cts/)

• Computational tools and softwares to calculate fate and ecotoxicity endpoints From the molecular structure knowledge -QSARs Predicting ecotoxicological endpoints ECOSAR : chronic toxicty for aquatic organisms

Not feasible for experimentation

In silico approaches (QSAR/QSPR) The structure of molecules is quantitatively correlated with molecular descriptors and reflect their physicochemical properties, which enable to predict the behavior of pesticide TPs in the environment respecting their parent compounds (PCs) • Some TPs can be assumed to have the same behavior as their parent compounds while others would be more persistent and/or toxic or, on the contrary, less persistent and/or toxic

• TyPol relies on the robustness of Input Data -> Increased knowledge from suspect screening approach -> Increased knowledge from predictive tools for exposure -> Increased knowledge from predictive tools for effects -> Also integrating more experimental values

Examples•

  ECOSAR TM (Ecological Structure Activity Relationships) : based on a linear relationships between the predicted log Kow values (EPI Suite KOWWIN prediction) and the associated log of the evaluated toxicity values (mmol/L) for fish, daphnids, and green algae 11th European Modelling Workshop 25-26 September 2022

q•Ø15Fig.•

  Fig. Circles of correlations of descriptors (red) and environmental parameters (blue)

•

  Potential use of TyPol for Pesticide TPs Environmental Risk Assessment -

2021), 6 Traore et al. (2018), 7 Benoit et al. (2017), 8 Storck et al. (2016) Tebuconazole 8

	New approach
	Rapid &	Servien et al. (2014)
	comprehensive tool to handle numerous	TyPol
	TPs for future risk
	assessment	PPCPs 5
	Hensen et al. (2020)	Several pesticides 6
		Chlordecone 7
	To predict environmental properties, fate,
	and toxicity of organic compounds
	5 Bonnot (

11th European Modelling Workshop 25-26 September 2022

Data preparation for Typol Database