Listeria monocytogenes is one of the most dangerous food-borne pathogens and is responsible for human listeriosis, a severe disease with a high mortality rate, especially among the elderly, pregnant women and newborns. Therefore, this bacterium has an important impact on food safety and public health. It is able to survive and even grow in a temperature range from -0.4°C to 45°C, a broad pH range from 4.6 to 9.5 and at a relatively low water activity (aW < 0.90), and tolerates salt content up to 20%. It is also resistant to ultraviolet light, biocides and heavy metals and forms biofilm structures on a variety of surfaces in food-production environments. These features make it difficult to remove and allow it to persist for a long time, increasing the risk of contamination of food-production facilities and ultimately of food. In the present review, the key mechanisms of the pathogen’s survival and stress adaptation have been presented. This information may grant better understanding of bacterial adaptation to food environmental conditions.

Various artisanal dairy products such as kariesh cheese, Laban Rayeb (a type of fermented fluid milk), zabady (a type of artisanal yoghurt), Butter milk and soured cream (a type of cream separted from skim milk after overnight natural fermentation of milk in earthenware pots) are poular for human consumption in Egypt. However, they are manufactured from raw milk depending on natural fermentation by wild microflora without guaranteed heat treatment processing or addition of permissible additives. Thus, the current study included the microbiological investigations on 50 samples of each of afore-mentioned products (total of 250 samples) primarily to isolate and discriminate different lactic acid bacteria (LAB) flora and secondly to search for some LAB to be further considered as a probiotic culture. Accordingly, several characteristics were investigated including, their ability to resist and survive gastrointestinal tract conditions represented in gastric acidity (pH 3) and duodenal bile acids, and at the same time, ability to produce antimicrobial substances such as organic acids (lactic acid), hydrogen peroxide and diacetyl. At the same time, the isolates were tested for having safety or non-pathogenicity, which principally includes non-harboring of antibiotic resistance (AR) features or blood haemolysis activity. Three important technological properties including the salt tolerance, β-galactosidase production and milk acidification ability were tested for selected isolates as important features needed for optimum fermentation by LAB as starter or non-starter cultures that can be incorporated in dairy processing. Finally, the LAB strains were tested as inhibitors for bacteria of food-safety concern such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. Our results showed that the examined fermented artisanal dairy products proved to harbor a wide variety of LAB microflora. After screening the probiotic, technological and safety related properties of 40 selected LAB isolates from examined products, 7 strains were proven to meet all required criteria, thus could be tested in future studies as promising strains to be incorporated in manufacture of various dairy products as starter and non-starter cultures.

We aimed to systematize and assess scientific information on tetracycline (TET) resistance genes in animals, products, and by-products in the Latin America and the Caribbean (LAC) region. PRISMA guidelines were followed. Only original articles published in peer-reviewed journals were considered. Sixty articles published between 2003 and 2023 met the inclusion criteria. The geographical areas of study were Brazil, Mexico, Chile, and Costa Rica, and, to a lesser extent, Colombia, Bolivia, Cuba, Jamaica, Puerto Rico, and Uruguay. The studies were related to livestock, wild animals, and pets. The most common isolated bacteria were Escherichia coli and Salmonella spp. The tet genes found in higher frequency in the samples or isolates evaluated were tetA, tetB, tetM, tetL, tetK, tetC, tetO, tetD, tetG, tetW, tetS, tetQ, tetE, tetH, tetJ, tetZ, and tetY. Studies evaluating the presence of tet genes in animals in LAC are limited despite TET being antibiotics widely used in animals. It is necessary to establish cross border public policies that allow the constant training of medical and related personnel regarding the responsible use of antibiotics in animals and the effective monitoring of the phenomenon in the region.