Microbiological quality of colonial cheese sold in Porto Alegre-RS

Abstract

Colonial cheese is a traditional dairy product in southern Brazil and is commonly purchased by the citizens of Porto Alegre. However, there is still a lack of technical regulation of colonial cheese, and there is little information about the microbiological quality of this product at the retail level. Thus, the objectives of this study were to (i) evaluate compliance with the legal microbiological standards of colonial cheese sampled from street fairs and the central market of the city of Porto Alegre; (ii) statistically test the hypothesis of an association between noncompliance with the standards and local purchasing (street fairs or central market); (iii) estimate the number of Listeria spp. and Listeria monocytogenes in the positive samples; and (iv) characterize the L. monocytogenes strains by serotyping and macrorestriction (PFGE). For this purpose, 205 cheese samples belonging to 17 different brands were analyzed. The microbiological analyses were conducted according to ISO standardized protocols for the detection of L. monocytogenes and Salmonella spp. or by enumeration of coagulase-positive Staphylococcus and coliforms at 45°C. Among the samples, 47.31% did not comply with at least one of the microbiological standards established by the Brazilian legislation and were thus unsuitable for human consumption. Regarding the coliforms at 45ºC and coagulase-positive Staphylococcus, 10.73% and 40.48% of the samples presented higher counts than the legal parameter, respectively. There was no association between the frequency of samples with coagulase-positive Staphylococcus counts above the legal parameter and local of purchasing; however, the commercial brand influenced the frequency of unsuitable samples. This may indicate failures of hygiene during cheese production. Salmonella spp. were not detected. Listeria monocytogenes was isolated from 2.9% of the samples. The estimated average populations of Listeria spp. and L. monocytogenes were low in the positive cheese samples at -3.3 log CFU g?1 and -2.26 log CFU g?¹, respectively. The strains of L. monocytogenes belonged to serovars 1/2a, 1/2b and 1/2c and could be grouped into five pulsotypes with no evident epidemiological relation among them. The results demonstrate the need to improve the hygiene procedures during colonial cheese production and to strengthen monitoring at the dairy plants and retail levels.

Bacteria and yeasts associated to Colonial cheese production chain and assessment of their hydrolytic potential

“…Some of the benefits observed for occasional milk or cheese consumers were the increase in lipid excretion and the decrease in blood cholesterol levels; however, it has not yet been established whether this is correlated to a specific microorganism (Robinson et al, 2021;Zheng et al, 2015). Although the microbial composition of cheeses can influence a multitude of factors, almost nothing is known about the microorganisms present in Colonial cheese, except for its main contributors (such as Lactic Acid Bacteria (LAB)) or its potential pathogens (Funck et al, 2015;Pereira et al, 2017;Jonnala et al, 2018;Ausani et al, 2019;Carvalho et al, 2019;Pegoraro et al, 2020). Further information can assist in identifying the product regarding probiotic characteristics and potential, and determining the geographic origin and/or the qualification of a regional cheese.…”

Kefir fermented milk as starter culture in Minas Frescal cheese production

“…There are two production models: industrial, mandatorily processed with pasteurized milk and "colonial" (farm cheese). It is considered farm cheese when its production is made with raw milk, less technology and generally sold without a label, it has been produced as a traditional subsistence dairy product on small farms for many years in the countryside of the country [4,5].…”