RESISTANCE OF MOULDS AND YEASTS ISOLATED FROM BOVINE RAW MILK TO PASTEURIZATION AND BOILING

Abstract

The objective of this study was to the evaluate the resistance of molds and yeasts isolated from bovine raw milk from dairy herds to pasteurization and boiling. A total of 27 molds (05 Mucor spp., 02 Aspergillus spp., 07 Chrysosporium sp., 05 Acremonium spp., 08 Penicillium spp.) and 275 yeasts (05 Aureobasidium sp., 50 Candida krusei, 22 Candida parapsilosis, 23 Candida kefyr, 03 Candida albicans, 40 Candida guilliermondii, 14 Candida lusitaniae, 36 Candida tropicalis, 33 Rhodotorula spp., 35 Geotrichum spp., 14 Trichosporon spp.) were submitted to the tests. The selected strains were originally isolated from 50 bulk tanks and 10 milk cans from dairy farms, and also from 10 milk cans of distributors that store and sell informal milk. High Temperature Short Time (HTST) pasteurization was the procedure in which there was a higher resistance (72.18%) of yeast and mold strains, followed by boiling (15.89%) and Low Temperature Long Time (LTLT) pasteurization (0.99%). Care should be taken regarding the possibility of fungi persistence in pasteurized and boiled milk, which can represent a risk to consumers. The resistance of yeasts and molds to thermal treatment represent a risk to the consumption of milk and dairy products, having in view that these microrganisms may cause diseases as well as interfere with the procedures used in the production of dairy products.