Mycological Quality Of Raw Bulk Milk From Farm Cooling Tanks In Argentina

VERÓNICA A. ALONSO ; STELLA M. CHIACCHIERA ; MARÍA LAURA GONZÁLEZ PEREYRA; LILIA R. CAVAGLIERI

Mendoza

Congreso; International Society of Mycotoxicology; 2011

The dairy cattle chain is one of the most important and dynamic agro-food systems in Argentina. It has international renown and is responsible for both economic and social development of many regional economies. The Cordoba province is the second in milk production within the country. There are three dairy basins in Cordoba; from which Villa Maria is the most important contributing with 50% of production. Current regulations in the country regarding the microbiology of milk (established in the Argentine Food Code) define the hygienic quality parameters for raw milk depending on the total bacteria counts and somatic cell counts. Fungi and yeasts are not yet considered relevant. However, clinically fungal infections in dairy cows have been found associated with mastitis. These infections were associated with the feed given to cattle, and isolated fungi were the same of those species causing mastitis. Contamination with fungi and yeasts in milk cow was detected in studies conducted in the Sao Paulo city, Brazil. Milk is a food of great importance in the diet of humans and mainly in children. The problems of pollution and quality of milk in Argentina have been extensively studied from the bacteriological point of view. Research on the incidence of fungi and their metabolites in milk has not been informed. The aim of this study was to carry out a survey of mycological contamination in raw whole milk from bulk tanks. The sample collection was performed in forty seven dairy farms located in Villa Maria basin, Argentina. The milking was done twice daily and fresh milk was stored in a refrigerated tank. Fungi total colonies were counted in DRBC and DG18 media through the surface plate method. The identification of fungal species was carried out following adequate taxonomic keys. The mycobiota analysis in raw milk showed total colony fungal counts (CFU) ranged from 1.00 x 102 to 2.00 x 104 CFU/ml. No differences in total CFU were observed in homogenized milk of tanks related to variations in feed diets. The incidence of yeasts was higher than 45%, being Saccharomyces cerevisiae, Rhodotorula mucilaginosa, Candida krusei, Candida parapsilopsis the most frequent species. Filamentous fungi contamination in raw milk was given predominantly by Aspergillus species followed by Penicillium and Fusarium species. Potentially toxigenic species such as F. verticillioides, A. flavus, A. fumigatus, and P. citrinum were prevalent and it represents a potential risk of mycotoxin contamination in milk Contamination with fungi and mycotoxins in milk depends largely on the hygiene of the dairy and the type of feeding. The initial quality of raw milk determines to a large extent the success of the pasteurization process and this in turn affects the hygienic quality of processed dairy products like cheeses reducing its useful life, deteriorated sensory and nutritional quality.