Evaluation of DAS™ kits for the detection of food-borne pathogens in chicken- and meat-based street-vended foods

Detection of Bacterial Pathogens and Antibiotic Residues in Chicken Meat: A Review

Detection of pathogenic microbes as well as antibiotic residues in food animals, especially in chicken, has become a matter of food security worldwide. The association of various pathogenic bacteria in different diseases and selective pressure induced by accumulated antibiotic residue to develop antibiotic resistance is also emerging as the threat to human health. These challenges have made the containment of pathogenic bacteria and early detection of antibiotic residue highly crucial for robust and precise detection. However, the traditional culture-based approaches are well-comprehended for identifying microbes. Nevertheless, because they are inadequate, time-consuming and laborious, these conventional methods are not predominantly used. Therefore, it has become essential to explore alternatives for the easy and robust detection of pathogenic microbes and antibiotic residue in the food source. Presently, different monitoring, as well as detection techniques like PCR-based, assay (nucleic acid)-based, enzyme-linked immunosorbent assays (ELISA)-based, aptamer-based, biosensor-based, matrix-assisted laser desorption/ionization-time of flight mass spectrometry-based and electronic nose-based methods, have been developed for detecting the presence of bacterial contaminants and antibiotic residues. The current review intends to summarize the different techniques and underline the potential of every method used for the detection of bacterial pathogens and antibiotic residue in chicken meat.

Knowledge, Attitudes, and Hygienic Practices of Boiled Hypocotyls (Borassus aethiopum Mart) Vended in the Streets of Cotonou City and Its Outskirts, Benin

In Benin, the boiled hypocotyl (Borassus aethiopum Mart) is one of the most common street foods consumed for its therapeutic properties. However, the knowledge, attitudes, and practices of boiled hypocotyl food sellers are poorly known despite the high contamination potential of these street foods. This study aimed to determine the knowledge, attitudes, and practices of boiled hypocotyls food vendors in the streets of Cotonou and its outskirts. The approach used concerned the process of good hygiene and production. Face-to-face interviews of 300 hypocotyls vendors and producers from Cotonou, Sèmè, Ouidah, and Abomey-Calavi were conducted. Concurrently, 200 samples of boiled hypocotyl were collected among study vendors. Results showed that all of the interviewed population (100%) of this activity are women. They are generally illiterate and 75% of them have never been to school. Additionally, 76.7% of street boiled hypocotyls sellers interviewed were mobile. The microbial profile of the boiled hypocotyls showed the lack of control and poor understanding of hygiene rules. The processes management also revealed two diagrams processes. The conditions in which hypocotyls vendors operate are largely unacceptable from a food safety point of view and an effort should be made to provide them with adequate infrastructure including potable water. In view of the socioeconomic impact of hypocotyl activities in Benin and their role in the unexpected arrival of food-borne diseases, vendors should be regularly trained in order to prevent outbreaks of food-borne illnesses.

Detection of viable Salmonella in ice cream by TaqMan real-time polymerase chain reaction assay combining propidium monoazide

Real-time polymerase chain reaction (PCR) allows rapid detection of Salmonella in frozen dairy products, but it might cause a false positive detection result because it might amplify DNA from dead target cells as well. In this study, Salmonella-free frozen ice cream was initially inoculated with heat-killed Salmonella Typhimurium cells and stored at −18°C. Bacterial DNA extracted from the sample was amplified using TaqMan probe-based real-time PCR targeting the invA gene. Our results indicated that DNA from the dead cells remained stable in frozen ice cream for at least 20 days, and could produce fluorescence signal for real-time PCR as well. To overcome this limitation, propidium monoazide (PMA) was combined with real-time PCR. PMA treatment can effectively prevent PCR amplification from heat-killed Salmonella cells in frozen ice cream. The PMA real-time PCR assay can selectively detect viable Salmonella at as low as 10³ CFU/mL. Combining 18 hours of pre-enrichment with the assay allows for the detection of viable Salmonella at 10⁰ CFU/mL and avoiding the false-positive result of dead cells. The PMA real-time PCR assay provides an alternative specifically for detection of viable Salmonella in ice cream. However, when the PMA real-time PCR assay was evaluated in ice cream subjected to frozen storage, it obviously underestimated the contamination situation of viable Salmonella, which might lead to a false negative result. According to this result, the use of enrichment prior to PMA real-time PCR analysis remains as the more appropriate approach.