Effects of moisture content and temperature on aflatoxin production in corn.
01 May 1970-Applied and Environmental Microbiology (American Society for Microbiology)-Vol. 19, Iss: 5, pp 781-784
TL;DR: Screening of the fungi present in the corn revealed aflatoxin production only by A. flavus, and the toxigenic strains produced only aflatoxins B(1) and B(2).
Abstract: Samples of freshly harvested and remoistened corn, of various moisture contents, were stored at different temperatures; analyses for aflatoxin content were made periodically. At moisture levels above 17.5% and at temperatures of 24 C or warmer, aflatoxins were formed by Aspergillus flavus present in the original epiphytic mycoflora. Remoistened dried corn was subject to more rapid fungal deterioration and aflatoxin formation than freshly harvested corn. Screening of the fungi present in the corn revealed aflatoxin production only by A. flavus. The toxigenic strains produced only aflatoxins B(1) and B(2).
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TL;DR: This review covers the epidemiology of A. flavus in preharvest corn from the infection process to the factors that influence aflatoxin formation and the problems associated with the development of resistant varieties.
Abstract: Aflatoxin B1 is a potent hepatacarcinogen that occurs in corn worldwide. The aflatoxin‐producing fungus Aspergillus flavus can grow and produce aflatoxin on corn preharvest and in storage. Within the U.S., aflatoxin contamination of preharvest corn has been reported in 23 states, and contamination is chronic in the southeastern U.S. where hot, drought conditions often favor the fungus and the production of aflatoxin. Management practices have been developed to reduce aflatoxin contamination, but in years when environmental conditions are extremely favorable for the fungus, no control strategy is effective. Resistance to aflatoxin accumulation appears to be heritable, but no commercial hybrids are available with adequate resistance. This review covers the epidemiology of A. flavus in preharvest corn from the infection process to the factors that influence aflatoxin formation. Also discussed are the problems associated with the development of resistant varieties and new strategies that are being de...
325 citations
TL;DR: In general, mold growth and mycotoxin production can be prevented by employing various measures based on knowledge of the factors involved, but choice of the measures depends upon the type of product, storage period and available techniques.
147 citations
131 citations
TL;DR: All antifungals showed inhibitory activity, but Imazalil and DDVP were the most effective agents at the lowest concentrations.
Abstract: Effect of temperature, pH, water activity, and nine antifungal agents on growth of Aspergillus flavus and A. parasiticus was determined on Sabouraud-Dextrose Agar and on corn. Maximal growth of the two molds occurred at 33°C, the highest temperature used, pH of 5.0 and aw of 0.99. At 15°C, growth was observed at aw of 0.95 but not 0.90. Slight growth was observed at an aw, of 0.85 at 27°C and 33°C. Nine antifungal agents (Botran, Orthocide, Poly-ram 80, Topsin-M, Thiram, Imazalil, sodium propionate, sodium sulfite and DDVP) were tested for inhibition of growth. Activity of the antifungals increased as the aw was decreased. All antifungals showed inhibitory activity, but Imazalil and DDVP were the most effective agents at the lowest concentrations.
123 citations
TL;DR: N nanoparticle-based electrochemical, piezoelectric, optical, and immunodipstick assays for aflatoxins have been developed and novel concepts and promising applications in the field of food safety are illustrated.
119 citations
Cites background from "Effects of moisture content and tem..."
...The 83 optimum temperature for Aspergillus is around 30 C and the chance of mildew contamination 84 increases if the crops are exposed to a high humidity environment.[35, 36] As a result, strict 85...
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References
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294 citations
TL;DR: Two aflatoxin-producing isolates of Aspergillus flavus were grown for 5 days on Wort media at 2, 7, 13, 18, 24, 29, 35, 41, 46, and 52 C and color of CHCl(3) extracts appeared to be directly correlated with aflatoxins concentrations.
Abstract: Two aflatoxin-producing isolates of Aspergillus flavus were grown for 5 days on Wort media at 2, 7, 13, 18, 24, 29, 35, 41, 46, and 52 C. Maximal production of aflatoxins occurred at 24 C. Maximal growth of A. flavus isolates occurred at 29 and 35 C. The ratio of the production of aflatoxin B1 to aflatoxin G1 varied with temperature. Aflatoxin production was not related to growth rate of A. flavus; one isolate at 41 C, at almost maximal growth of A. flavus, produced no aflatoxins. At 5 days, no aflatoxins were produced at temperatures lower than 18 C or higher than 35 C. Color of CHCl3 extracts appeared to be directly correlated with aflatoxin concentrations. A. flavus isolates grown at 2, 7, and 41 C for 12 weeks produced no aflatoxins. At 13 C, both isolates produced aflatoxins in 3 weeks, and one isolate produced increasing amounts with time. The second isolate produced increasing amounts through 6 weeks, but at 12 weeks smaller amounts of aflatoxins were recovered than at 6 weeks. Images
142 citations
117 citations
TL;DR: Moisture content of immature kernels was higher at equilibrium with the same relative humidity than the moisture content of sound mature kernels, damaged kernels, or kernels from unshelled peanuts, but there appeared to be no proportional quantitative correlation between synthesis of aflatoxin and production of free fatty acids in nonliving peanuts.
Abstract: Sound mature kernels, broken mature kernels, immature kernels, and unshelled Early Runner peanuts were heat-treated in controlled environment cabinets and inoculated with spores ofAspergillus flavus Treatments were incubated at 97–99% relative humidity at different temperatures ranging from 5 to 55C and also at 30C with relative humidities ranging from 55 to 99% Samples were removed after 7 and 21 days and assayed for aflatoxin, free fatty acids, and peanut kernel moisture The limiting relative humidity for aflatoxin production byA flavus was 85±1% relative humidity for 21 days at 30C The limiting low temperature for visible growth and aflatoxin production by the fungus was 13±1C for 21 days at 97–99% relative humidity Damaged kernels, however, developed some afllatoxin in 21 days at 12C The maximum temperature for aflatoxin production was 415±15C for 21 days at 97–99% relative humidity Fungus growth and sporulation at 43C were equal to that at 40C, but no aflatoxin was produced Moisture content of immature kernels was higher at equilibrium with the same relative humidity than the moisture content of sound mature kernels, damaged kernels, or kernels from unshelled peanuts There appeared to be no proportional quantitative correlation between synthesis of aflatoxin and production of free fatty acids in nonliving peanuts, but no aflatoxin was produced without a simultaneous increase in free fatty acids
96 citations