Diversidade genética e potencial deteriorante de fungos leveduriformes e filamentosos isolados em queijos tipo minas frescal comercializados informalmente na região norte do Tocantins

Abstract

Cheese is a product resulting from the enzymatic coagulation of milk, complemented or not with specific lactic bacteria. The common cheese composition favors the multiplication of pathogenic microorganisms. The fungal contamination of this product can compromise the quality, as these agents have a high deteriorating potential, in addition to posing risks to public health. The objective of this study was to verify the genetic diversity and the damaging potential of yeast and filamentous fungi isolated in 20 samples of Minas Frescal cheeses sold illegally, in open markets in the northern region of Tocantins. Filamentous and yeast-yeast fungi counts were performed, verification of proteolytic, lipolytic and saccharolytic activity at different temperatures of the obtained isolates. The amplification of the internal transcribed spacer regions (ITS) of the DNA, sequencing and identification by similarity using the BLAST tool for comparison with the sequences deposited in the GenBank of the National Center for Biotechnology Information (NCBI). It was observed that 45% of the cheese samples had the presence of filamentous fungi and 100% the presence of yeasts, with an average count of 7.6 (± 2.6) x 105 CFU / g. The predominant genus of filamentous fungus was Penicillium spp., Representing 47.36% (9/19) of morphospecies, being a genus known for containing mycotoxin-producing species. The predominant yeast species was Kluveromyces lactis followed by Clavispora lusitaniae. Of the isolated filamentous fungi 73.68% (14/19) have proteolytic potential, with four (21.05%) growing in both mesophilic and psychrotrophic temperatures. The proteolytic activity of yeasts was 64% (16/25), of which 37.50% (6/16) of these produced proteases at psychrotrophic temperature. Of the filaments, 89.47% (17/19) had lipolytic activity, in which 57.89% produced lipases at the two temperatures submitted. Regarding yeasts, 92% (23/25) had lipolytic activity and 86.95% (20/25) were psychrotrophic. Regarding the acidifying activity in different sugars, most of the isolates had a greater action on dextrose, both filamentous and yeast. It is concluded that clandestine cheeses marketed in open markets in Araguaína are unsuitable for consumption and public policies are needed that enhance health education and that inspection is more intensive, preventing the illegal commercialization of products and by-products of animal origin that may pose a risk. to the consumer.