Abstract

In Côte d’Ivoire, Braised beef or “Choukouya”, is particularly appreciated for its unique taste. She is a staple of street food. Consequently, it may be contaminated with potentially pathogenic germs due to vendor hygiene, inadequate cooking, preparation and sales conditions, or exposure to open air on the streets. This study evaluated the levels of beef contamination sold in Abidjan by Escherichia coli and Staphylococcus aureus, while analyzing sales practices and conditions that could affect public health. A survey was conducted with 600 consumers and 150 ʺchoukouyaʺ vendors. Additionally, 300 beef samples fresh and braised were collected, including 100 from slaughterhouses, 100 from markets, and 100 braised samples. Contamination by E. coli and S. aureus was evaluated using enumeration methods on TBX and enriched Baird-Parker media. The results highlighted the popularity of ʺchoukouyaʺ in diets. However, contamination factors were identified, notably poor hygiene of meat, ingredients, vendors, and sales environments. All fresh meat samples were contaminated with E. coli and S. aureus. Average microbial loads were 2.2 ± 3.1 log10 CFU/g (E. coli) and 3.9 ± 3.5 log10 CFU/g (S. aureus) for fresh meat from slaughterhouses, and 2.1 ± 3.5 log10 CFU/g and 3 ± 3.6 log10 CFU/g, respectively, for market-sourced meat. Braised meat showed loads of 0.1 ± 0.7 log10 CFU/g (E. coli) and 1.2 ± 2.2 log10 CFU/g (S. aureus). These results underscore the urgent need to strengthen hygiene measures to ensure the safety of beef.

1. Introduction

According to the World Organization for Animal Health, meat refers to all edible parts of an animal (any mammal or bird). It is also the product of the transformation of muscle after the death of the animal ¹. In Côte d'Ivoire, meat occupies an important place in the diet and eating habits of Ivorians. The most frequently consumed meats are beef, poultry, pork, mutton and goat. In 2017, total meat consumption per capita reached 13 kg per year, including 4.9 kg of beef, 4.2 kg of pork, 2.6 kg of poultry and 1.2 kg of mutton and goat meat (including edible by-products of slaughter, called "edible offal") ². Beef therefore ranks first in consumption and is the second preferred source of animal protein for the population after fish. Its richness in proteins, vitamin B12 and minerals makes it essential to the human diet balance ^{1 3}. It is consumed in various forms including braised, dried, fried and many others ⁴.

The braised form, commonly called "barbecue" in Europe, "Dibi" in Senegal, "Tchatchanga" in Benin and "Choukouya" in Ivory Coast, is particularly appreciated by Ivorians. Approximately 62.4% of the population consumes meat in this form ⁵. It is widely consumed in leisure places, recreational places and festive events ^{6 7}. It is sold on the edges of the streets, in markets and neighborhoods, making it a street food. Consequently, it can be contaminated by potentially pathogenic germs including Escherichia coli and Staphylococcus aureus due to the hygiene of the seller, inadequate cooking, preparation and sale conditions, or exposure to the open air. The large share of this informal activity, as well as survey data linking it to foodborne diseases, make braised beef a significant threat to public health ^{8 9}. However, given the limited data on the sale, consumption and microbiological quality of braised beef “choukouya” in Abidjan, it is crucial to assess its safety. Thus, the objective of this study was to assess the contamination levels of beef sold in Abidjan by Staphylococcus aureus and Escherichia coli while identifying attitudes and conditions of sale that could impact public health.

2. Material and Methods

The biological material consisted of fresh beef sourced from the Abidjan city slaughterhouse (Figure 1), fresh beef from the Port-Bouët market (Figure 2), and braised beef (Figure 3).

The study was conducted in the autonomous district of Abidjan (latitude 5°18’34’’ N and longitude 4°00’45’’ W), located in the Lagunes region in southern Côte d’Ivoire. Since 2001, Abidjan has been designated an "autonomous district" covering 2,119 km². It encompasses the ten communes of the former city of Abidjan (422 km²) and four peripheral sub-prefectures, which were previously rural but are now urbanized due to the city's expansion. As of the 2021 census, Abidjan had a population of 6,321,017, representing 21.5% of the country's total population ¹⁰. Abidjan is not only Côte d’Ivoire’s largest city but also home to the country's largest livestock market. Among the district's communes, Port-Bouët, Koumassi, Treichville, Marcory, and Yopougon were selected for conducting the survey with consumers and vendors of braised beef (Figure 4). Port-Bouët was chosen due to the presence of a slaughterhouse in the area, the high number of choukouya beef vendors, and a dedicated space for selling this type of meat. Koumassi, Treichville, and Marcory were selected for their proximity to Port-Bouët and their high concentration of choukouya beef vendors. Finally, Yopougon was included because of its large population and notable presence of choukouya beef vendors.

The size of the population to be surveyed was determined using the formula for calculating the sample size in probabilistic studies ¹¹.

(1)

In this formula: n is the minimum population size for the survey; Z is a constant from the normal distribution ; for a 95% confidence level, (Z = 1.96); p is the prevalence of consumption and sale of braised beef ; e chosen margin of error (5%).

Given the lack of national data on the consumption rate of braised beef, a prevalence of p = 50% was used for this study to estimate the survey population size. With a prevalence of 50%, the minimum required sample size would be 384. In total, 750 individuals were surveyed, including 150 vendors and 600 consumers.

The survey of vendors was conducted in the selected communes over two months, from January to February 2023, targeting 150 vendors (30 per commune). Only vendors selling choukouya braised beef were approached and interviewed with their consent. The survey was conducted using a pre-designed questionnaire completed based on the vendors' responses. The questionnaire covered sociodemographic characteristics such as age, gender, and nationality, as well as sales practices, the selling environment, and hygiene conditions (of both the vendors and the sales locations).

The survey of consumers was also conducted in the same selected communes from January to February 2023, involving 600 consumers (120 per commune). Participants were randomly selected among buyers of braised beef ʺchoukouyaʺ, as well as individuals present near the sales points or simply passing by. The questionnaire covered various aspects, including the participants' level of knowledge and consumption habits related to beef, the form and frequency of consumption, and any history of symptoms experienced after consuming ʺchoukouyaʺ. Sociodemographic data such as age, gender, and nationality were also collected with the participants' consent.

The sample size for fresh and braised beef was determined using the same formula applied to calculate the survey population size.

To account for the type of matrix and the bacterial strains being investigated, prior study data were considered. According to research by ⁵ conducted in Bouaké and Korhogo, the prevalence of E. coli strains in fresh and braised beef was 88.9% and 66.7%, respectively, while the prevalence of S. aureus strains was 100% in both fresh and braised beef.

Based on an expected prevalence of 80%, the minimum probabilistic sample size would be 246. However, to account for uncertainties, 300 samples of fresh beef and braised ʺchoukouyaʺ beef were collected for this study.

A total of 300 samples (n=300) were collected randomly from butchers and vendors in the Port-Bouët commune. This included 100 samples of fresh beef from the slaughterhouse, 100 samples of fresh beef purchased from the market, and 100 samples of braised beef. After purchase, each sample was labeled with the location, date of collection, and sample number, then quickly stored and transported to the laboratory in coolers with ice packs to ensure optimal conditions for the analyses.

The mother suspensions and decimal dilutions were prepared according to the ¹² AFNOR NF V08-010-2 : 1996 standard. Fresh and braised meat samples were aseptically weighed, cut with sterile scissors, and ground in a mortar that had been previously disinfected and sterilized with a Bunsen burner flame. Then, 10g of the ground sample was transferred into 90mL of buffered peptone water contained in sterile test tubes. The resulting mother suspension was used to prepare a series of serial dilutions. A volume of 1 mL from the mother suspension was taken with a sterile graduated pipette and added to 9 mL of buffered peptone water in a sterile test tube. This mixture was homogenized, and decimal serial dilutions were made up to the 10⁻⁴ dilution for the fresh meat samples and to the 10⁻¹ dilution for the braised meat samples.

The enumeration of S. aureus was carried out by counting characteristic colonies after plating on Baird-Parker agar supplemented with potassium tellurite and egg yolk, following the ¹³ AFNOR NF V 08-057-1 standard. 0.1 mL of the mother suspension and decimal dilutions were spread onto the surface of Baird-Parker agar (Biomerieux, France). The inoculated Petri dishes were incubated at 37°C for 24 hours, and if no colonies were visible, the incubation was extended for an additional 24 hours. After 48 hours, characteristic S. aureus colonies (black, shiny, convex, surrounded by a clear halo) were counted. For enumeration, only plates containing between 15 and 150 characteristic colonies were considered.

The enumeration of E. coli was performed on a selective chromogenic medium, TBX (Tryptone Bile X-Glucuronide) (Biomerieux, France). 0.1 mL of the mother suspension and decimal dilutions were spread onto the surface of pre-poured TBX agar in sterile Petri dishes. The plates were incubated inverted at 37°C for 24 hours. After 24 hours, characteristic E. coli colonies (blue or blue-green in color) were counted. For enumeration, only plates containing between 15 and 150 characteristic colonies were considered.

The survey data were entered and processed using IBM SPSS Statistics 26 software. Graphs were created using Excel 2016. The calculation of microbial loads was carried out using R software.

3. Results

All the braised beef “choukouya” sellers interviewed were male (100%). Most of them (48.7%) were aged 30–45 years and the majority were foreign nationals (59.3%). Among them, 82% sold only beef, while 9.3% sold both beef and chicken choukouya, 6% sold both beef and mutton choukouya, and 2.7% sold a mixture of beef, mutton and chicken choukouya. The majority of the sellers interviewed were illiterate (62.7%) or had a primary education level (30.7%), with 50.7% having less than 5 years of experience (Table 1).

The majority of vendors reported washing the meat (84.7%) and the vegetables (75.3%) used for preparing ʺchoukouyaʺ. However, some vendors (15.3%) stated they did not wash the meat, and 24.7% did not wash the vegetables. After cooking, the meat is mostly wrapped in paper used for packaging cement (66%), typically purchased from suppliers of fresh meat. Leftover meat is either stored in a refrigerator (84%) or at room temperature (16%). Most of the vendors surveyed operate their businesses along the roadside (58.7%), inside a market (14%), or in residential neighborhoods (27.3%). More than half of the vendors (64.7%) were considered to have sufficient personal hygiene, while 52.7% of the vendors were operating in an environment that was deemed unsatisfactory in terms of cleanliness (Table 2).

The profile of beef consumers was determined following the consumption survey. 100% of those interviewed stated that they know and consume beef. The majority were men (57.5%) with an age range between 18 and 30 years (50%). Most of them were Ivorian (81.2%), had a higher education level (46.2%), and were single (70.5%) (Table 3). The different forms of consumption identified were: braised, in sauce, fried, dried, and boiled. Among these, 45.5% of consumers prefer the grilled form, 36.2% prefer it in sauce, 10.5% prefer it fried, and 7.8% prefer it boiled. The braised form, or "choukouya," is mostly consumed on the side of the streets (49.5%), in local bars (4.8%), and in homes (9.7%). The results regarding the frequency of consumption show that 15.5% of consumers eat grilled beef at least once a day (Figure 5).

Among the 100% of consumers surveyed, 69% stated that they consume beef in braised form, 74.3% in sauce, 41.2% fried, 27.2% boiled, and 14.2% dried. Among the consumers of the grilled form "choukouya," 27.6% reported experiencing discomfort after consuming beef in this form. The recorded discomforts included nausea, vomiting, abdominal pain, and diarrhea. Diarrhea was the most commonly recorded symptom (52.9%), followed by abdominal pain (20.7%), diarrhea associated with abdominal pain (7.4%), and nausea associated with vomiting (5%) (Figure 6). These discomforts affected mainly consumers in the age range of 18-30 years (50.4%) (Figure 7).

All 200 fresh beef samples from the slaughterhouse and the Port-Bouët market were contaminated with E. coli and S. aureus, resulting in a contamination rate of 100%. The baised beef samples, or "choukouya," had a contamination rate of 6% for E. coli and 30% for S. aureus (Table 4).

In the fresh beef samples from the slaughterhouse, the average load of E. coli was 2.2 ± 3.1 log10 CFU/g, while that of S. aureus reached 3.9 ± 3.5 log10 CFU/g. For the fresh beef from the market, the average load of E. coli was 2.1 ± 3.5 log10 CFU/g, and that of S. aureus was 3 ± 3.6 log10 CFU/g. Regarding the "choukouya" samples, the average load of E. coli was 0.1 ± 0.7 log10 CFU/g, and that of S. aureus was 1.2 ± 2.2 log10 CFU/g (Table 5).

4. Discussion

The survey of consumers of braised beef “choukouya” made it possible to assess the place that this dish occupies in the diet of Ivorians, as well as the consumption habits associated with it. All the people interviewed in the different communes knew and consumed beef. Among the different forms of consumption, braised beef, commonly called “choukouya”, emerged as the most consumed and appreciated, with a rate of 45.5%. This preference can be attributed to several factors, including its accessibility and availability, as it is easily found in many neighborhoods, especially near maquis (local restaurants), markets and street corners. In addition, its delicious taste, attractive aroma and affordable price allow many people to enjoy it, while for others, it is simply a matter of personal preference. In fact, consumers surveyed said they preferred grilled beef for its taste (24.2%), availability (13.7%), smell (13.3%) and personal preference (15.5%).

Analysis of fresh beef samples from the slaughterhouse and market, as well as braised beef “choukouya”, revealed that all samples were contaminated with at least one of the microorganisms studied, namely E. coli and S. aureus, with contamination levels ranging from 6% to 100%. Fresh beef had the highest contamination rate (100%). This high contamination rate could be mainly attributed to the animal itself, from which the meat is derived ¹. The skin, digestive and respiratory organs of animals serve as reservoirs for microorganisms, which could thus serve as a source of contamination. In addition, poor hygiene practices in slaughterhouses, as well as inadequate hygiene during slaughtering, skinning, storage and transport, could also lead to contamination of meat by various pathogenic germs, including those isolated in this study. The slaughterhouse therefore appears to be a critical area for bacterial proliferation ¹. In addition, climatic conditions (ambient temperature) unsuitable for the preservation of fresh meat ¹⁴, could exacerbate the bacterial load during the retail sale of meat at ambient temperature, which may exceed acceptable limits.

These factors could also explain or justify why the bacterial loads observed in the samples from the slaughterhouse were higher than those from the market. Indeed, fresh meat from the slaughterhouse had a mean E. coli load of 2.2 ± 3.1 log10 CFU/g and S. aureus of 3.9 ± 3.5 log10 CFU/g, while the mean bacterial loads of the market samples for E. coli and S. aureus were 2.1 ± 3.5 log10 CFU/g and 3 ± 3.6 log10 CFU/g, respectively. In contrast to the slaughterhouse, the meat sold in the different markets was less loaded, because the vendors took the time to clean and remove parts of the meat that could repel customers, thus reducing the bacterial load. As for the samples of braised beef "choukouya" they were contaminated by E. coli and S. aureus at respective rates of 6% and 30%. These values, which are much lower than those of fresh meat, could be explained by the fact that unlike fresh meat, braised meat undergoes several treatments before cooking, not forgetting a heat treatment consisting of eliminating or even destroying all the microorganisms that could contaminate the meat.

However, although these rates are lower, the presence of these microorganisms in cooked meats, ready to be consumed, could indicate either inadequate cooking or poor hygiene practices. Indeed, the presence of E. coli in braised beef indicates a hygiene deficiency ¹⁵, and a possible presence of enteropathogenic microorganisms, likely to cause foodborne infections ¹⁶. The contamination rates observed in braised beef are much lower than those observed by ⁵ for the same microorganisms in their study on the microbial risks associated with the consumption of braised beef in Côte d'Ivoire, more precisely in the cities of Bouaké and Korhogo.

The level of S. aureus contamination in braised beef is much higher than that of E. coli. This difference may be due to the fact that S. aureus, which naturally inhabits the mucous membranes, skin and nasopharyngeal region ¹⁷, is found when there is sweat on the skin surface ¹⁸ of vendors who have constantly sweaty hands due to profuse sweating ⁵. This leads to manual contamination of any object or food that comes into contact with these hands.

In addition, observation of vendors, their sales practices and their sales environment revealed several reasons that could be responsible for the potential contamination of braised beef, including E. coli and S. aureus. The treatment of meat before cooking could be a real source of contamination. The conditions in which meat is packaged for transport are often unsatisfactory, with large quantities being transported unpackaged in wheelbarrows or car trunks. Meat is also left at room temperature on vendors' tables, uncovered, while they prepare the elements needed for cooking. During cooking, the ingredients used in the preparation of "choukouya", such as onions, tomatoes, peppers, etc., are exposed to the open air and are not washed before being added to the preparation. After cooking, the wood used to cut raw meat is also used for cooked meat.

Indeed, raw meat debris left between the wood gaps could be a source of contamination ¹⁹. Chili powder mixed with other powders, such as “kankankan” from dubious sources, added after cooking, as well as fresh vegetables usually handled by hand, could be a source of contamination. In addition, the cement paper used to wrap “choukouya” could be a source of contamination. In fact, all vendors interviewed reported using this paper, which they usually purchase from their meat suppliers for packaging. This type of packaging, although hazardous to consumer health, is used because it is cheap, unlike aluminum foil which is a suitable but relatively expensive packaging option ¹⁹. For this activity, vendors are usually located along the public road, and the meat is exposed to the open air. Microorganisms present in the air, dust and vehicle exhaust gases come into contact with the “choukouya” and can be sources of contamination. The seller’s environment, sometimes unsanitary, could also be a source of contamination. All these reasons listed could justify the bacterial loads of E. coli and S. aureus observed in the “choukouya”. In fact, the average bacterial load of E. coli was 0.1±0.7 log10 CFU/g, and that of S. aureus was 1.2±2.2 log10 CFU/g.

During this study, several consumers (20.2%) reported experiencing discomfort after consuming “choukouya”. These symptoms included nausea, vomiting, abdominal pain, and diarrhea. These symptoms may be due to the consumption or ingestion of food contaminated with E. coli or S. aureus. In fact, E. coli infections are usually caused by enterohemorrhagic E. coli strains, the most well-known of which is O157:H7, which has a strong epidemiological link with beef ²⁰. These infections occur following the consumption of contaminated and undercooked beef and can lead to hemorrhagic colitis, diarrhea, etc. ^{21, 22}. Regarding S. aureus infections, symptoms include nausea, vomiting, and abdominal cramps with or without diarrhea ²³. However, the symptoms reported by consumers do not allow direct attribution of the cause to E. coli and S. aureus as the causative pathogens, as the symptoms may also have a non-infectious origin. Furthermore, no stool samples were collected from the sick consumers in this study to confirm this link. It should also be noted that these symptoms could be caused by microorganisms other than E. coli and S. aureus ¹.

5. Conclusion

The information obtained from the surveys allowed for the identification of various high-risk practices that could serve as sources of contamination for choukouya braised beef, as well as the potential health issues related to its consumption. The study also revealed that both fresh and braised beef were contaminated with Escherichia coli and Staphylococcus aureus. The fresh beef from the slaughterhouse was found to be the most contaminated, particularly with S. aureus, which exceeded acceptable limits by a large margin. In contrast, the choukouya braised beef was the least contaminated, with levels of S. aureus and E. coli being significantly below the acceptable limits. However, the study highlighted the need for improved safety measures and hygiene practices to ensure the beef sold to consumers is free from health risks. Ensuring better hygiene and food safety protocols is crucial to protect public health and prevent foodborne illnesses.

ACKNOWLEDGEMENTS

The authors are thankful to the slaughterhouse and market in Port-Bouët for sampling.

References