Ma. Refugio Torres-Vitela

Dr. Ma. Refugio Torres-Vitela


Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 September 2021 in Applied Sciences
Verified
Journal Article
Open access
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MOMaría de Los Ángeles Olea-Rodríguez
María de Los Ángeles Olea-Rodríguez
PCPatricia Chombo-Morales
Patricia Chombo-Morales
KNKarla Nuño
Karla Nuño
OVOlga Vázquez-Paulino
Olga Vázquez-Paulino
Zuamí VillagránZuamí Villagrán
Zuamí Villagrán
MTMa. Refugio Torres-Vitela
Ma. Refugio Torres-Vitela
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.