Microbiological Characteristics and Behavior of Staphylococcus aureus, Salmonella spp., Listeria monocytogenes and Staphylococcal Toxin during Making and Maturing Cotija Cheese

Abstract

Cotija cheese is an artisanal matured Mexican cheese from unpasteurized milk. This work determined the microbiological characteristics and behavior of Staphylococcus aureus, Salmonella spp., Listeria monocytogenes and staphylococcal toxin during cheese elaboration and ripening. Sixteen 20-kg cheeses were used, eight inoculated with 6 log CFU/mL of each pathogen, and eight uninoculated, and samples were taken at each stage of the process. In the uninoculated samples, the survival of S. aureus and L. monocytogenes decreased after 30 days of ripening. The average counts of S. aureus in milk, curd, and serum were 7 log MPN /mL, and 8.7 log MPN /g in cheese, decreasing from day 15. Salmonella spp. counts (initial inoculum: 7.2 log MPN /mL) decreased after 24 h, and L. monocytogenes counts (8.7 log MPN/g at 24 h) decreased from day 15 in the cheese. Salmonella spp. and L. monocytogenes were not detected in any sample after 60 days of ripening, unlike S. aureus, which was detected at the end of the study. Lactic acid bacteria counts were 9 log CFU/mL in milk and whey and 7.2 log CFU/g in cheese. Pathogens behavior during the ripening process reduces the health risks by consuming products made with unpasteurized milk when subjected to ripening.

Utilization of Whey for Eco-Friendly Bio-Preservation of Mexican-Style Fresh Cheeses: Antimicrobial Activity of Lactobacillus casei 21/1 Cell-Free Supernatants (CFS)

“…Mexican-style fresh cheeses are commonly consumed, and it is well known that they are associated with foodborne diseases [6]. For this reason, this study investigated the ability of the CFSs to help reduce the risk associated with these products.…”

“…Raw milk used in cheese production may contain pathogens such as E. coli, Listeria, Salmonella, and S. aureus [6,9,12]. These pathogens can survive and spread during cheese production if the milk is not pasteurized correctly or becomes contaminated during handling [52].…”

“…It is common for this variety of cheese to be a vehicle for pathogenic microorganisms, which can be attributed to unpasteurized milk or handling techniques during its production [4]. Unfortunately, there have been multiple cases of illness linked to the consumption of this cheese, as it may contain harmful microorganisms such as Salmonella [5][6][7], Listeria monocytogenes [8][9][10], Escherichia coli [11,12], and Staphylococcus aureus [6,13,14].…”

Recent Advances in Applied Microbiology and Food Sciences

“…Olea-Rodríguez et al [2] investigated the properties and behavior of Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, and staphylococcal toxin during the development and maturation of Cotija cheese. Cotija cheese is a semi-hard Mexican cheese that comes from a town called Cotija de la Paz in the state of Michoacan.…”

Rapid-Response Magnetic Enrichment Strategy for Significantly Improving Sensitivity of Multiplex PCR Analysis of Pathogenic Listeria Species

“…Among the genus Listeria, Listeria monocytogenes and Listeria ivanovii have been classified as important human and animal pathogens and are widely distributed in food [2]. Human infections are caused by L. monocytogenes and L. ivanovii mainly through eating contaminated food [3], such as meat products [4], vegetables [5], dairy products [6], and seafood [7], while animal infections are caused by the ingestion of organisms through contaminated vegetation. Human infection with pathogenic Listeria spp.…”