Microbiological and mycotoxicological correctness of protein feed ingredients in Vojvodina

Abstract

During 2009 and 2010, the microbiological tests of a total of 40 samples of protein feed ingredients (sunflower meal, soybean, soybean cake, soybean grits and soybean meal) originating from Vojvodina were carried out. The most of the samples (57.5%) matched the Serbian regulations on feed. Microbiologically, there was not adequate quality of protein ingredients, which was a consequence of the presence of pathogenic bacteria: Proteus spp. in 12 samples of sunflower meal, 1 sample of soybean meal and 2 samples of soybean cake, and E. coli in 2 samples of soybean meal. The highest total number of bacteria (1 x 107 g-1) and the highest number of yeasts and molds (148.000 g-1) was identified in one sample of sunflower meal. Mycological analysis of protein feed established the dominance of species from the genera Aspergillus (A. flavus, A. fumigatus, A. niger and A. ochraceus), Fusarium (F. solani, F. subglutinans and F. verticillioides) and Mucor (Mucor hiemalis f. hiemalis and M. racemosus f. racemosus). The study of biochemical characteristics of 10 fungal isolates from sunflower meal, soybean grits and cake has established that: a) 2 cultures of Aspergillus spp. possessed antagonistic activity against other fungal species, b) 1 isolate F. solani biosynthesized T-2 toxin, c) 1 culture of F. subglutinans produced zearalenone, d) 4 isolates of Mucor spp. showed the ability to degrade one or both trichothecenes of type A (diacetoxyscirpenol - DAS and T-2 toxin). Mycotoxicological studies that included 24 samples of protein ingredients showed the absence of mycotoxins (aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, DAS and T-2 toxin) in all 15 samples of sunflower meal. In the samples of soybean and its products (meal and cake) only T-2 toxin was detected in 3 analyzed samples. The amount of this fusariotoxin did not exceed 375 ?g kg-1 .