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Use of food-borne bacteria to prevent growth and mycotoxin production by Fusarium graminearum |
J. STILES and L. B. Bullerman. Dept. of Food Science & Technology, Univ. of Nebraska, Lincoln, 349 Food Industry Bldg., Lincoln, NE 68583-0919 Certain food-borne bacteria and their metabolites have recently been shown to have antifungal properties worthy of further study. The objective of this work was to study the ability of Bacillus pumilus NE B1 and Lactobacillus rhamnosus VT1 to inhibit growth and mycotoxin production of Fusarium graminearum, a cause of ear rot disease of corn and head blight or “scab” of wheat and barley. The specific objective was to investigate the ability of live cells of both bacteria and skim milk fermented by L. rhamnosus VT1 to inhibit mycelial growth and the production of deoxynivalenol (DON) and zearalenone (ZEN) in sterile rice and corn substrates. Fusarium graminearum NRRL 5883 was grown simultaneously with live cells of each bacterial strain and re-constituted freeze-dried milk fermented by L. rhamnosus VT1 in sterile steamed maize and long grain white rice for 14 days. The inhibition of mycelial growth was assessed using visual observations, while the amount of DON and ZEN produced was determined by high performance liquid chromatography with fluorescence detection. To varying degrees, the antifungal agents inhibited mycelial growth as well as mycotoxin production. Bacillus pumilus NE B1 was found to have the strongest antifungal and antimycotoxigenic activity (95.7% to 99.1%) in both substrates, followed by live cells of L. rhamnosus VT1 (64.5% to 92.0%) and milk fermented by L. rhamnosus VT1 (45.9% to 82.0%), respectively. It should be also noted that when both substrates were treated with B. pumilus NE B1, there was no visual mold growth detected. Percentages of inhibition of DON and ZEN production by all three agents ranged between 45.9% and 97.3%, and 68.7% and 96.4%, for each toxin respectively. These results suggest that the bacterial strains tested have potential as biocontrol agents of molds and mycotoxins in cereal grains and food commodities, and warrant further study.
Session 43, Food Microbiology: Food mycology
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