Inhibition of growth and mycotoxin production of aspergllus and penicillium by some selected food additives [Eugenol, soeugenol and monolaurin]

ABSTRACT

Sabouraud dextrose agar was prepared to contain up to 300 ppm of eugenol, isoeugenol or monolaurin. Eight strains of mycotoxin and non-mycotoxin producing Aspergillus spp. and Penicillium spp. were tested in this study. Spore suspensions of the molds were spotted in the center of agar plates and the linear [radial] growth rate was monitored during incubation. All agents inhibited mold growth on agar surface, but isoeugenol and eugenol were more effective than monolaurin. The average decrease in linear growth rate in the presence of eugenol, isoeugenol and monolaurin was 62, 51 and 21% at 100 ppm and 84, 88 and 26% at 200 ppm, respectively. At 300 ppm of eugenol and isoeugenol, the surface growth of all fungi was inhibited completely. However, monolaurin up to 2000 ppm did not prevent the growth of the molds. Molds tested, except P. viridicatum NRRL 6062, did not vary significantly [at P = 0.05] in degree of inhibition by a particular antifungal agent. A. parasiticus was grown in modified yeast extract dextrose broth containing 100 ppm of the antifungal agents. Decreases in mycelial dry weight in the presence of eugenol, isoeugenol or monolaurin were 5.3, 7.9, 10.5%, respectively, and the corresponding reductions in aflatoxin B1 synthesized were 58, 57 and 25%. In conclusion, eugenol and isoeugenol have strong antifungal properties which are best manifested when the surface growth of molds on solid media is monitored