Isolamento microbiológico e confirmação molecular de Salmonella spp. em queijos minas frescal não inspecionados comercializados em feiras livres no município de Uberlândia (MG)

Abstract

Minas Frescal Cheese (MFC) is one of the most widely consumed dairy products in Brazil, owing to its high nutritional value and broad consumer acceptance. However, due to its high moisture content and lack of ripening, it is highly susceptible to microbiological contamination when produced and sold without sanitary inspection or the adoption of Good Agricultural and Manufacturing Practices. Under such conditions, its consumption can pose a public health risk, as dairy products are frequently implicated in foodborne disease outbreaks, with Salmonella spp. standing out as a primary etiological agent. Thus, this study aimed to evaluate the occurrence of Salmonella spp. in uninspected Minas Frescal Cheeses sold at open-air markets in the municipality of Uberlândia, Minas Gerais. Samples from 25 cheeses, collected between June and July 2026, were analyzed. Salmonella spp. detection was performed according to ISO 6579-1, followed by molecular confirmation of isolates via polymerase chain reaction (PCR) targeting the ompC and invA genes. The frequency of Salmonella spp. positivity was compared against current regulations (RDC nº 724/2022 and IN nº 161/2022) and across collection days using Fisher's exact test, with a significance level of 5% (p<0,05). Of the 25 samples evaluated, 13 (52%) tested positive for Salmonella spp. Twenty isolates were obtained: two tested positive only for the ompC gene, six exclusively for invA, and twelve tested positive for both genes. A significant association was observed between the day of sale and the occurrence of Salmonella spp. (p = 0,0414), with a higher frequency in samples collected on Mondays (68,75%) compared to those collected on Thursdays (22,22%). Furthermore, cheeses sold on Mondays were 7,70 times more likely to test positive for Salmonella spp. (OR = 7,70; 95% CI: 1,129–42,83). The results demonstrate a high prevalence of Salmonella spp. in uninspected cheeses, indicating a public health risk and the need to strengthen sanitary control measures.