Reduce Aflatoxin Contamination Research Articles

Sambiloto (Andrographis paniculata Nees.) for reducing aflatoxsins contamination in commercial chicken feed

Indonesian climate condition is suitable for growing of mold such as Aspergillus flavus. The mold grown in feed and feed ingredients cause aflatoxins contamination of the feed. Sambiloto has been reported to reduce the growth of Aspergillus flavus and aflatoxins production in feed isolate. The aim of the study was to find the used of sambiloto in reducing aflatoxins contamination in commercial chicken feed. The feed was homogenously mixed then divided into 4 groups with 3 replicates. The samples were treated with sambiloto 0.04%, 0.08% and 0.16% respectively into the feed, except for the control feed sambiloto was not added. Into these feed 4 ml of Aspergillus flavus suspension was also added. Then the feed in each group was incubated at room temperature for 10 days. Samples were collected from each group at days 0, 5 and 10 of incubation times for aflatoxins analysis. Samples were extracted and aflatoxins were detected by High Performance Liquid Chromatography (HPLC). Observation results indicated that sambiloto concentration of 0.16% in feed can inhibit the total aflatoxins production of 16.46% and gave the inhibitation percentage of aflatoxin B1 of 45.39%. Statistical test showed that the used of sambiloto in feed for 5 days incubation times gave significant result in reducing aflatoxins production. However the 10 days incubation times of the feed with sambiloto gave in significant result. It is suggested that to get optimum inhibition of aflatoxins production, sambiloto added in feed should be higher than 0.16%. Key words : Feed, aflatoxin, sambiloto

Aspergillus Colonization and Aflatoxin Contamination in Peanut Genotypes with Resistance to Other Fungal Pathogens.

Indirect selection tools would be valuable in the development of peanut (Arachis hypogaea) cultivars with resistance to aflatoxin contamination. The objective of this study was to determine whether resistance to other fungi could be used as an indirect selection tool for resistance to colonization of peanut by Aspergillus flavus group fungi or aflatoxin contamination. Nine peanut genotypes with resistance to late leaf spot (Cercosporidium personatum) or white mold (Sclerotium rolfsii) were evaluated for 2 years at Tifton, GA, and Yuma, AZ. Plots were subjected to late-season heat and drought stress. None of the genotypes exhibited less colonization of shells or kernels by A. flavus group fungi than cv. Florunner when tested in Georgia or Arizona. None of the genotypes showed a reduced level of aflatoxin contamination in comparison to Florunner at either location. These results indicate that the mechanisms of resistance to other fungi operating in these genotypes are not effective in providing resistance to colonization by A. flavus group fungi or reducing aflatoxin contamination. Therefore, resistance to these fungi cannot be used as an indirect selection tool for resistance to aflatoxin contamination.

Developments in solar drying using forced ventilation and solar regenerated desiccant materials

In many countries, grains are naturally sun dried in the field, resulting in large-scale spoilage. Purpose-built solar grain dryers are being introduced with some success, but to be effective, their performance must be carefully controlled to prevent cracking of grains, fungal growth and aflatoxin production during storage. This paper describes some of the performance aspects of an autonomous solar desiccant maize dryer developed for village use in Kenya. Since most commercial desiccants are expensive, a low cost solid desiccant was fabricated from bentonite clay and calcium chloride materials. This desiccant is capable of regeneration at 45°C, has high moisture sorption of 45% (dwb), significantly extends the drying process at night and reduces aflatoxin contamination of the grain. Laboratory and field testing took place to determine the drying performance and allow conclusions to be drawn. This showed the prototype dryer had the capability of drying 90kg of fresh maize from 38% (dwb) to 15% (dwb) within 24 hours.

Development of greenhouse screening for resistance to Aspergillus parasiticus infection and preharvest aflatoxin contamination in peanut.

Aspergillus flavus Link ex Fries and A. parasiticus Speare can invade peanut kernels and under certain environmental conditions produce unacceptable levels of the mycotoxin aflatoxin. A concerted effort is underway to reduce aflatoxin contamination in peanut and peanut products. A potentially effective method of control in peanut is the discovery and use of genes for resistance to either fungal invasion or aflatoxin formation. The objective of the present experimental study was to develop an effective and efficient procedure for screening individual plants or pods of single plants for resistance to invasion by the aflatoxigenic fungi and subsequent aflatoxin production. Methods of obtaining adequate drought-stress and fungal infection were developed through this series of experiments. By completely isolating the pods from the root zone and imposing drought-stress only on pegs and pods, high levels of fungal infection were observed. High amounts of preharvest aflatoxin accumulation were also produced by completely isolating the pods from the root zone. Mid-bloom inoculation with A. parasiticus-contaminated cracked corn and drought-stress periods of 40 to 60 days were the most effective procedures. This technique was used to assess peanut genotypes previously identified as being partially resistant to A. parasiticus infection or aflatoxin contamination, and segregating populations from four crosses. Variability in aflatoxin contamination was found among the 11 genotypes evaluated, however, none were significantly lower than the standard cultivars. Broad-sense heritability of four crosses was estimated through evaluation of seed from individual plants in the F2 generation. The heritability estimates of crosses GFA-2 x NC-V11 and Tifton-8 X NC-V11 were 0.46 and 0.29, respectively, but mean aflatoxin contamination levels were high (73,295 and 27,305 ppb). This greenhouse screening method could be an effective tool when genes for superior aflatoxin resistance are identified.

Formulating Atoxigenic Aspergillus flavus for Field Release

A procedure was developed to encapsulate mycelia of an atoxigenic strain of Aspergillus flavus in alginate pellets for seeding into agricultural fields in order to reduce aflatoxin contamination via competitive exclusion. Kaolin, a clay filler commonly employed in alginate formulations, was detrimental to pellet performance as measured by spore yield. Corn cob grits, a by-product of the corn industry, was found to be an excellent replacement for kaolin. Of nine nutritive adjuvants tested, wheat gluten improved pellet performance the most, although gluten concentrations above 5% were difficult to process. The best formulation tested consisted of 1% sodium alginate, 5% corn cob grits and 5% wheat gluten. On a 'per gram' basis, this alginate formulation yielded more spores than either A. flavus sclerotia or colonized wheat seed. Pesticides were also tested as adjuvants with potential use for protecting pellets under field conditions. Only one (chloramphenicol) of four tested pesticides (the others were dichloran, rose Bengal and cyfluthrin) reduced pellet sporulation. Formulations with or without pesticide adjuvants retained similar spore yield potential during a 2-year storage at 8 C. However, spore production in stored products lagged behind that of fresh products. At 75% relative humidity (RH), pellet storage stability decreased with increasing temperature from 27 to 42 C. Pellet spore yield at 32 C decreased as RH decreased from 100 to 90%. Sporulation occurred at 90% RH but not at 88% RH. Spore yield varied widely in four field tests, and the cumulative spore yield was inversely correlated (r2= -0.798, P 0.01) with rainfall. The results suggest that alginate pellets may be effective formulations for delivery of atoxigenic A. flavus strains to furrow-irrigated cotton in desert environments, where aflatoxin contamination of cottonseed is most severe.

Flavor, Color and Texture of Peanuts Treated with Hydrogen Peroxide1

Abstract Treatment of aflatoxin-contaminated peanut kernels in 0.075% hydrogen peroxide for 1 min has been proposed to reduce aflatoxin contamination by 90%. The effect of hydrogen peroxide treatment on the flavor quality, texture and color was, therefore, investigated. Two hundred grams of peanuts were submerged in a solution containing 0, 0.075 or 0.225% hydrogen peroxide for 1 and 3 min. Treated peanuts were dried to 8-9% moisture, blanched and stored in plastic bags for 0, 1, 2 and 3 weeks at 39 C. Peak areas identified as hexanal increased with increasing hydrogen peroxide concentration, regardless of the treatment and storage time. No significant differences in peak areas identified as ethanol were observed after a 3-week storage time, regardless of the concentration of hydrogen peroxide and treatment time. Hydrogen peroxide treatment and storage of treated peanuts did not significantly affect the lightness (L), chroma (C) and texture of the treated peanuts. Furthermore, sensory analysis conducted on peanut brittle prepared from raw peanuts and peanuts treated with 0.075% hydrogen peroxide for 1 min showed no significant difference between the two samples evaluated.

Aflatoxin in maize

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...

Preharvest Aflatoxin Contamination in Maize: Resistance and Genetics 1

AbstractPreharvest aflatoxin contamination of maize (Lea mays L.) gram by Aspergillns spp. is a concern to both producers and consumers of maize. Aflatoxms are carcinogenic to animals and have been linked to liver cancer in humans. The most desirable solution for eliminating or reducing aflatoxin contamination is to identify and/or develop sources of resistance. However, only a few genetic studies, which utilized a limited amount of genetic material, have been conducted. A thorough review and consolidation of information from these studies was deemed necessary. The purpose of this paper is to present a current, critical review on aspects of infection by Aspergillus, role of insects, inoculation techniques, and sources and genetics of resistance as they relate to aflatoxin production in maize. Damage to maize kernels by insects, especially the European corn borer (Ostrinia nubilalis Hübner), fall armyworm (Spodoptera frugiperda J. E. Smith), and corn ear‐worm (Helicoverpa zea Boddie), has been associated with high aflatoxin levels. Artificial inoculation techniques that damage maize kernels generally result in the highest and most consistent aflatoxin levels. Although, a relatively large amount of maize germplasm has been screened for resistance and varying levels of resistance have been identified, additional germplasm needs to be systematically evaluated. To date, there are no known genotypes with complete resistance. Results from the few genetic studies indicated that additive genetic effects controlled resist‐Preharvest aflatoxin contamination of maize (Zea mays L.) gram by Aspergillns spp. is a concern to both producers and consumers of maize. Aflatoxms are carcinogenic to animals and have been linked to liver cancer in humans. The most desirable solution for eliminating or reducing aflatoxin contamination is to identify and/or develop sources of resistance. However, only a few genetic studies, which utilized a limited amount of genetic material, have been conducted. A thorough review and consolidation of information from these studies was deemed necessary. The purpose of this paper is to present a current, critical review on aspects of infection by Aspergillus, role of insects, inoculation techniques, and sources and genetics of resistance as they relate to aflatoxin production in maize. Damage to maize kernels by insects, especially the European corn borer (Ostrinia nubilalis Hübner), fall armyworm (Spodoptera frugiperda J. E. Smith), and corn ear‐worm (Helicoverpa Zea Boddie), has been associated with high aflatoxin levels. Artificial inoculation techniques that damage maize kernels generally result in the highest and most consistent aflatoxin levels. Although, a relatively large amount of maize germ‐plasm has been screened for resistance and varying levels of resistance have been identified, additional germplasm needs to be systematically evaluated. To date, there are no known genotypes with complete resistance. Results from the few genetic studies indicated that additive genetic effects controlled resistance to aflatoxin contamination in maize. Aflatoxin production on maize grain appeared to be greatly influence by the environment. Further genetic studies, utilizing additional germplasm, are warranted for a better understanding of the nature of resistance to asflatoxin contamination in maize. Future research needs and plans relative to resistance to aflatoxin contaminaton in maize are presented.

Aflatoxin in Corn Hybrids Field Inoculated with Aspergillus flavus

AbstractCorn (Zea mays L.) genotypes with resistance to Aspergillus flavus Link ex Fr. are needed to reduce aflatoxin contamination of grain. The primary objective of this study was to determine if the pinbar inoculation technique was effective in separating hybrids for resistance and susceptibility to kernel infection by A. flavus and aflatoxin contamination of the grain at a number of locations, but other inoculation techniques were evaluated at individual locations. Two single crosses, Mo18W × Mp313E and SC54 × Tx601, previously classified as resistant to kernel infection by A. flavus and two susceptible crosses, Mp68:616 × SC212M and GT106 × T202, were used. We found that hybrids previously classified as resistant to kernel infection by A. flavus had fewer kernels infected and lower aflatoxin concentration in the corn grain at harvest. However, these differences were not significant at all locations. Over six locations, resistant hybrids contained 58% less aflatoxin in the grain and 41% fewer infected kernels than susceptible hybrids. In addition to the pinbar, the side‐needle, and to a lesser extent the knife inoculation technique, differentiated hybrid response to ear inoculation with A. flavus.

IMPACT OF HUSK TYPE AND SPECIES OF INFESTING INSECTS ON AFLATOXIN CONTAMINATION IN PREHARVEST CORN AT TIFTON, GEORGIA

The use of plants that resist insects has been suggested as a potential means of reducing aflatoxin contamination in some crops. Dent corn, Zea mays L., germplasm possessing the characteristic of a relatively tight, complete husk cover and germplasm possessing the characteristic of a relatively loose, incomplete husk cover on the ear were evaluated for 3 years at Tifton, GA, for aflatoxin contamination. In two of the three test years, corn ears with tight, complete husk cover sustained significantly lower mean amounts of aflatoxin than ears with loose, incomplete husk cover following artificial inoculation with Aspergillus flavus Link spores. Ears hand-infested with maize weevils, Sitophilus zeamais (Motschulsky), sustained significantly higher amounts of aflatoxin (329 ng·g−1) than ears infested with fall armyworms, Spodoptera frugiperda (J. E. Smith), (80 ng·g−1), European corn borers, Ostrinia nubilalis (Hübner), (71 ng·g−1), or corn earworms Heliothis zea (Boddie) (60 ng·g−1). Overall, ears in the check (inoculated with A. flavus only) sustained significantly lower aflatoxin (37 ng·g−1) amounts than ears from plots supplemented with insects. Although insects were not applied in the check plots, some damage was observed on the ears.

Reducing Aspergillus Species Infection of Peanut Seed Using Resistant Genotypes

AbstractStudies were conducted to determine the potential of reducing aflatoxin contamination using recently released peanut (Arachis hypogaea L.) genotypes found to be resistant to seed invasion by aflatoxin‐producing strains of Aspergillus Link ex Fr. flavus and A. parasiticus Speare. Under certain environmental conditions these fungi metabolize aflatoxins which are highly potent carcinogens when ingested by animals. Resistant lines (GFA‐1, GFA‐2, AR‐1, AR‐2, AR‐3, and AR‐4) were evaluated for resistance to seed invasion and colonization of intact, dry seed by the Aspergillus species. When rehydrated and inoculated seed were incubated under favorable conditions, all the resistant peanut lines were more resistant than commercial peanut cultivars, “Florunner” and ‘Sunbelt Runner’, in successive years of evaluating. Pod yields of GFA‐1 and GFA‐2 pod yields approached those of the commercial cultivars. AH the resistant genotypes could reduce contamination of seed immediately following harvest or in short term storage when environmental conditions are conducive to A. flavus and A. parasiticus infection.

Reduction of Aflatoxin Contamination in Corn by Irrigation and Tillage

Reduction of Aflatoxin Contamination in Corn by Irrigation and Tillage

Correlation of Aflatoxin Contamination With Zinc Content of Chicken Feed

Feed samples from chicken houses in five commercial chicken operations were analyzed for Zn, Mn, Fe, Cu, Cd, and aflatoxin content. Mean aflatoxin content of these samples was 14 ppb (14 ng/g) as opposed to 1.2 ppb in samples taken when the feed was made. Aflatoxin content of the feed samples correlated (r = 0.325) significantly (P < 0.05) with Zn content but not with Mn, Fe, or Cu, all of which correlated significantly with Zn. Zn content of unamended feed (<20 ppm [20 mug/g]) is normally supplemented with a mineral premix containing Zn, Mn, Fe, and Cu to meet the nutrient requirements of chickens (40 ppm of Zn). The mean zinc concentration of the feed samples (117 ppm) was about threefold greater than the nutrient requirement and ranged from 58 to 162 ppm in individual samples. These field survey results parallel earlier reports of augmented production of aflatoxin in monocultures of aflatoxigenic fungi in corn and other ingredients supplemented with Zn. These results suggest that stricter control of Zn levels during manufacture could reduce aflatoxin contamination of feed consumed by chickens.

Factors influencing the inhibition of aflatoxin production in corn by Aspergillus niger.

Aspergillus niger, a mold commonly associated with Aspergillus flavus in damaged corn, interferes with the production of aflatoxin when grown with A. flavus on autoclaved corn. The pH of corn-meal disks was adjusted using NaOH-HCl, citric acid-sodium citrate, or a water extract of A. niger fermented corn. Aflatoxin formation was completely inhibited below pH 2.8-3.0, irrespective of the system used for pH adjustment. When grown in association with A. flavus NRRL 6432 on autoclaved corn kernels, A. niger NRRL 6411 lowered substrate pH sufficiently to suppress aflatoxin production. The biodegradation of aflatoxin B1 or its conversion to aflatoxin B2a were eliminated as potential mechanisms by which A. niger reduces aflatoxin contamination. A water extract of corn kernels fermented with A. niger caused an additional inhibition of aflatoxin formation apart from the effects of pH.

The Destruction of Aflatoxins in Peanuts by Microwave Roasting

The effectiveness of microwave roasting for reducing aflatoxin contamination in peanuts was investigated. Contaminated peanuts were treated in a specially constructed experimental microwave unit in 2kg batches for various times at two different power levels. The results suggest that aflatoxin contamination can be consistently reduced by better than 95% by heating the nuts to a temperature of at least 150°C. The rate of heating appears to have very little or no effect since similar results were obtained for a 5min treatment at a power level of 3.2kW and a 16min treatment at 1.6kW. These treatments also resulted in a satisfactory degree of browning, while protein and fatty acid content were not measurably affected. The operating cost of a microwave processor is estimated to be 1.5¢/kg.

Reducing aflatoxin contamination in peanut genotypes by selection and breeding

AbstractThe potential for developing agronomically suitable cultivais using peanut genotypes that exhibit resistance to seed colonization by aflatoxin‐producing strains ofAspergillus species is explored. Some factors found to be associated with the nature of resistance to seed colonization by the toxin‐producing fungi are cell structure, cell arrangement, permeability, waxy surface, tannin content and amino acid components of the seed testae. The practical implications of developing resistant cultivars are presented in data for yield, value and seed quality for 6 advanced peanut lines that were developed by breeding and selection from crosses.

Control of Aflatoxin Production During Fermentation of Wild Rice

The effect of water content of wild rice on aflatoxin production by Aspergillus flavus growing in the rice during fermentation, and influences of processing steps as means to reduce aflatoxin contamination were investigated. Aflatoxin was either not detected or rarely observed during 31 days of storage when rice saturated with water or adjusted to contain 33% water was inoculated with spores of A. flavus and stored at 25 C. Detectable amounts of aflatoxin developed in rice maintained at 20% moisture. Aflatoxin B1 content of contaminated fermented wet wild rice was reduced by parching. Aflatoxin analyses of hulls and kernels from parched rice indicated that most of the aflatoxin B1 remained in the hulls; however, detectable amounts of aflatoxin B1 were present in hulled rice kernels. When wild rice was sterilized with ethylene oxide, saturated with water, stored at 25 C, and inoculated with A. flavus, the mold grew if the rice was mixed daily, but only 10 ppb aflatoxin appeared after 19 days of storage. A. flavus did not grow in similarly treated rice that was not mixed.