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THE INHIBITORY EFFECTS OF SELECTED HERBS, SPICES, AND OTHER PLANT MATERIALS ON MYCOTOXIGENIC MOLDS
Abstract
The present series of investigations were conducted to study the antifungal effects of 16 selected herbs and spices, 3 commercial chemical antifungal agents, and 9 other food materials and the growth of selected mycotoxigenic molds. The effective levels of herbs and spices, found to have antifungal activity in preliminary experiments, on growth and mycotoxin production, were determined. The active antifungal agent(s) in white mustard, responsible for inhibition of aflatoxin-producing Aspergillus flavus, was identified. Of all samples tested, cloves, cinnamon, mustard, allspice, garlic, and oregano at a 2% level completely inhibited the growth of all selected mycotoxigenic molds. Pomegranate peel (powdered) at 2% level was a good inhibitor against all four Penicillium strains. Potassium sorbate at a 0.3% level was the most effective of all three compounds investigated followed by sodium benzoate and calcium propionate, respectively. The antibiotic (primaricin) at 5 ppm inhibited all mold strains tested. The remaining compounds, spices, and food materials were either non-inhibitory or showed only slight inhibition. Combinations of low levels of potassium sorbate and cloves showed synergistic effects against all mold strains, which indicates possible use in small amounts to still give the desired effect. At a level of 8 mg/ml YES media, both cloves and cinnamon completely inhibited mold growth and mycotoxin production of all selected mold strains, while mustard, allspice, garlic, and oregano levels that inhibited mold growth and the mycotoxin production were from 16 to 32 mg/ml, from 4 to 64 mg/ml, and from 16 to 64 mg/ml YES media, respectively. Five mycotoxigenic molds produced mycotoxins in decreasing amounts when allowed to grow, except in the case of patulin production by both P. patulum and P. roquefortii, where herbs and spices were effective inhibitors of patulin production even though mycelial growth occurred. A method of extracting white mustard using chloroform as the solvent was designed which made it possible to identify allyl isothiocyanate through the application of thin layer chromatography (TLC), gas liquid chromatography (GLC), infrared spectrophotometry (IR), and mass spectrometry (MS). Allyl isothiocyanate at 225 ppm completely inhibited the growth of Aspergillus flavus (NRRL 16100). The mycelial weight decreased significantly with increasing allyl isothiocyanate, as did aflatoxin production. Under the conditions of this study and at about 400 ppm, p-hydroxy benzyl isothiocyanate and its precursor sinalbin at 0.2% of white mustard showed no inhibitory effect on A. flavus (NRRL 16100). This constitutes the first report of the effect of the six previously mentioned herbs and spices on mycotoxigenic Penicillium strains and identification of allyl isothiocyanate as an active constituent in white mustard. This will contribute to the body of information available on the relative value and potential of herbs and spices as possible food preservatives.
Recommended Citation
AZZOUZ, MUFTAH ALI, "THE INHIBITORY EFFECTS OF SELECTED HERBS, SPICES, AND OTHER PLANT MATERIALS ON MYCOTOXIGENIC MOLDS" (1981). ETD collection for University of Nebraska-Lincoln. AAI8118152.
https://digitalcommons.unl.edu/dissertations/AAI8118152