Abstract

Aspergillus spp. grow on foods and feeds generating aflatoxins, which is the most potent carcinogen, therefore the present study aimed to evaluate the deactivation of growth and aflatoxin production of A. flavus and A. parasiticus in the presences of hematoporphyrin dihydrochloride and LED light. One hundred samples of different meat products (hamburger, luncheon, sausage and pastrami) have been used for the study. The isolates were identified classically and molecularly by amplification of ITS regions. The aflatoxin regulatory gene (aflR gene) was amplified and a phylogenetic tree was employed to aflR gene and the AFLR protein sequences. Different concentrations of haematoporphyrin combined with visible light (530 nm) were tested against aflatoxin-producing Aspergillus isolates in vitro and in vivo, using a piece of hamburger. A total of nineteen isolates (15 A. flavus and 4 A. parasiticus) were recovered from the collected samples. Aflatoxin-B1 was detected in 6 isolates (4 A. flavus and 2 A. parasiticus), and aflR gene sequences was assigned in GenBank accession no. KY769955-KY769960. The phylogenetic analysis of aflR genes and the predicted AFLR protein sequences among the strains were greater than 94%. haematoporphyrin photosensitization completely inhibited the growth and aflatoxin production in vitro and in vivo of both A. flavus and A. parasiticus at a concentration of 250 µg/ml. The biochemical analysis of the contaminated hamburger piece showed a decrease in the protein, carbohydrates, and fat content. The results suggest that haematoporphyrin–mediated photosensitization has a potential effect on the inhibition of the growth, spore formation and aflatoxin production of Aspergillus strains in meat products.

Key words: Key words: Hematoporphyrin, LED, Aspergillus, Aflatoxin, meat products