The sale of ready-to-eat (RTE) street food represents an important source of income in many developing countries. However, these foods are frequently implicated in outbreaks of gastrointestinal diseases. Street food vendors face several constraints that hamper improvement in the microbiological quality of their products. The aim of this review was to update knowledge about the main causes of foodborne illnesses in developing countries, including the growing concern with the microbial transmission of antibiotic resistance. Following PRISMA guidelines, this systematic review was conducted on original articles published from January 2010 to July 2023. The search was carried out using Scopus, PubMed, Web of Science, Food Science and Technology Abstracts (FSTA), the International Information System for Agricultural Sciences and Technology (AGRIS), as well as isolated searches of relevant articles from Google Scholar. The initial search identified 915 articles, 50 of which were included in this systematic review. The results indicate that, in the majority of the 15 countries examined, women constitute the predominant segment of street food vendors, representing more than 55% of the total number of these vendors. In 11 countries, street food vendors under the age of 18 were identified. Most vendors had a low level of education and, consequently, were unaware of good hygiene practices when handling food. The combination of factors such as poor hygiene practices on the part of food handlers and the lack of facilities, namely, the absence of available potable water, were frequently listed as the main causes of food contamination. Enterobacteriaceae such as Escherichia coli (61.9%), Salmonella (30.1%), and Shigella spp. (9.5%), as well as Staphylococcus aureus (30.1%) and Listeria monocytogenes (14.3%), were the most common pathogens found in RTE street foods. In 22 studies from 13 developing countries, 59% (13/22) reported high multidrug resistance in Enterobacteriaceae (40% to 86.4% in E. coli, 16.7 to 70% in Salmonella, and 31 to 76.4% in S. aureus). To address the challenges faced by street vendors and improve their economic activities, it is necessary for government entities, consumers, and vendors to work together collaboratively.

The persistence of certain Listeria monocytogenes strains in food-related environments suggests niche adaptation of these strains and therefore constitutes a major risk to consumer health and results in economic losses for the food producer. In this study, a set of 23 L. monocytogenes isolates, including a group of persistent and a group of sporadic strains, was evaluated regarding their swarming motility at 11°C. In each group, significant (p<0.05) differences in motility were observed. The transcript levels of nine cold stress-related genes were analyzed by real-time quantitative PCR in two representatives of persistent (CBISA3077) and sporadic (CBISA3049) strains isolated from the dairy environment, and significant (p<0.05) differences between the two strains were observed. The persistent strain showed significantly higher transcript levels of dtpT and sigB genes, and significantly lower levels of flaA, oppA, lmo1722, and lmo0866 genes. In the persistent strain, the upregulation of sigB, involved in the tolerance to low temperature and to osmotic stress, could account for the persistence of this strain in its original dairy environment. In a similar way, the downregulation of two helicase-encoding genes lmo1722 and lmo0866, in this strain, may be an evolutionary trait that could facilitate cold stress adaptation. Even though this analysis should be extended to more sporadic and more persistent strains, the results presented here strongly suggest gene expression networks differently adjusted, in the two strains, to the low-temperature environment from where they were collected. Moreover, our findings suggest that bacterial motility per se should not be considered a key feature for the persistence of L. monocytogenes in the food environment.

Pineapple is consumed on a large scale around the world due to its appreciated sensorial characteristics. The industry of minimally processed pineapple produces enormous quantities of by-products (30–50%) which are generally undervalued. The end-of-life of pineapple by-products (PBP) can be replaced by reuse and renewal flows in an integrated process to promote economic growth by reducing consumption of natural resources and diminishing food waste. In our study, pineapple shell (PS) and pineapple core (PC), vacuum-packed separately, were subjected to moderate hydrostatic pressure (225 MPa, 8.5 min) (MHP) as abiotic stress to increase bromelain activity and antioxidant capacity. Pressurized and raw PBP were lyophilized to produce a stable powder. The dehydrated samples were characterized by the following methodologies: chemical and physical characterization, total phenolic compounds (TPC), antioxidant capacity, bromelain activity, microbiology, and mycotoxins. Results demonstrated that PBP are naturally rich in carbohydrates (66–88%), insoluble (16–28%) and soluble (2–4%) fiber, and minerals (4–5%). MHP was demonstrated to be beneficial in improving TPC (2–4%), antioxidant activity (2–6%), and bromelain activity (6–32%) without affecting the nutritional value. Furthermore, microbial and mycotoxical analysis demonstrated that powdered PC is a safe by-product. PS application is possible but requires previous decontamination to reduce the microbiological load.

The food-borne pathogen Listeria monocytogenes is the causative agent of the severe human and animal disease listeriosis. The persistence of this bacterium in food processing environments is mainly attributed to its ability to form biofilms. The search for proteins associated with biofilm formation is an issue of great interest, with most studies targeting the whole bacterial proteome. Nevertheless, exoproteins constitute an important class of molecules participating in various physiological processes, such as cell signaling, pathogenesis, and matrix remodeling. The aim of this work was to quantify differences in protein abundance between exoproteomes from a biofilm and from the planktonic state. For this, two field strains previously evaluated to be good biofilm producers (3119 and J311) were used, and a procedure for the recovery of biofilm exoproteins was optimized. Proteins were resolved by two-dimensional difference gel electrophoresis and identified by electrospray ionization-tandem mass spectrometry. One of the proteins identified in higher abundance in the biofilm exoproteomes of both strains was the putative cell wall binding protein Lmo2504. A mutant strain with deletion of the gene for Lmo2504 was produced (3119Δ lmo2504 ), and its biofilm-forming ability was compared to that of the wild type using the crystal violet and the ruthenium red assays as well as scanning electron microscopy. The results confirmed the involvement of Lmo2504 in biofilm formation, as strain 3119Δ lmo2504 showed a significantly ( P < 0.05) lower biofilm-forming ability than the wild type. The identification of additional exoproteins associated with biofilm formation may lead to new strategies for controlling this pathogen in food processing facilities.