Micoflora and aflatoxigenic strains in commercial pet food in Argentina

- FERNANDEZ-JURI M. G., ASTORECA, A., BARBERIS C., ASILI R., ROSA C.A.R., DALCERO A.M., MAGNOLI C.

Nantes, Aperdpa Francia

Congreso; 10th Congress of the European Society of Veterinary and Comparative Nutrition, Congress Proceedings; 2006

Information about fungi associated with foods and feeds is important in assessing risk of mycotoxin contamination. Dog and cat food are prepared with vegetables and/or meat, cereal grains, vitamins and minerals. The filamentous moulds most commonly found in stored cereal grains are Aspergillus, Penicillium and Fusarium species. They are ubiquitous, can cause food spoilage and biodeterioration, and are capable of producing many mycotoxins. The aims of this work were to give information about the fungal contamination in dry pet foods and evaluate the toxigenic capacity by strains of Aspergillus section Flavi. A total of twenty five samples of dry pet foods were collected from a market located in the south of Córdoba province, Argentina. Isolation of moulds was carried out by the spread surface method. The cultures media used were dichloran-rose-bengal-chloranphenicol agar (DRBC) and dichloran-chloranphenicol 18% glycerol agar (DG18). The average number of colonies on the triplicates plates was recorded and the number of mould refers to CFU per gram of sample. Each strain isolated was identified to genera level (Pitt and Hocking, 1997). Aspergillus species were identified according to Klich (2002). The strains of Aspergillus flavus and A. parasiticus were evaluated for their ability to produce aflatoxins in extract malt agar according to Geisen (1996), the extraction of toxins was made with chloroform and detection by TLC and confirmed by HPLC method. Mycological examination of the samples indicated the presence of seven genera of filamentous fungi. The most frequent moulds was Aspergillus sp., followed by Eurotium sp., Cladosporium sp., Absidia sp., Rhizopus sp. and Alternaria sp. in others. Aspergillus flavus and Aspergillus section Nigri contaminated a high percentage of samples. The samples showed moderate levels of contamination (10-2 to 10-3 CFUg-1). A high percentage of A. flavus strains was aflatoxin- producing. The levels of AFB1 produced by these strains ranged from 2 to 66.25 µg g-1. The data presented in this study confirm the toxigenic fungi contamination could represent an hazard for cats and dogs. Careful control of raw material and environmental conditions in dry pet food elaboration are recommended in order to preserve the toxigenic fungi growth and mycotoxins production.