Inhibitory effect of spice oils on lipase and mycotoxin production.

Five spice oils were tested for their inhibitory activity towards the growth, respiration, lipase and mycotoxin productions by Aspergillus parasiticus var. globosus IMI 120920 and A. fumigatus. Cumin, onion, garlic and clove oils completely inhibited sterigmatocystin production. Cumin, onion and clove oils significantly suppressed aflatoxin production. Most of tested oils exhibited considerable inhibition on mycelial growth. Incorporation of these oils in basal medium suppressed lipase production with variable degrees. Onion oil was the most effective one. All spice oils significantly reduced or completely suppressed CO2 evolution of A. fumigatus, whereas CO2 evolution of A. parasiticus was slightly enhanced by these oils except with cumin and clove. Our results suggest that the use of spice oils may offer some advantage in the prevention of mycotoxin production.