This review of Fusarium ear blight (scab) of small grain cereals has shown that up to 17 causal organisms have been associated with the disease, which occurs in most cereal-growing areas of the world. The most common species were Fusarium graminearum (Gibberella zeae), F. culmorum, F, avenaceum (G, avenacea), F, poae and Microdochium nivale (Monographella nivalis). The disease was recorded most frequently under hot, wet climatic conditions where significant yield losses and mycotoxin accumulation in grain were reported. Possible sources of inoculum were reported as crop debris, alternative hosts and Fusarium seedling blight and foot rot of cereals. The mode of dispiersal of inoculum to ears remains unclear, but contaminated arthropod vectors, systemic fungal growth through plants, and wind and rain-splash dispersal of spores have been proposed. Infection of wheat ears was shown to occur mainly during anthesis, and it has been demonstrated that fungal growth stimulants may be present in anthers. Despite the importance of the disease, particularly during epidemic years, control methods are limited. Much effort has gone into breeding resistant wheat varieties and into improving our understanding of the possible mechanisms and genetic basis of resistance, with only moderate success. There are also surprisingly few reports of successful fungicidal or biological control of the disease in the field.

Fusarium ear blight (scab) in small grain cereals—a review

Review on the toxicity, occurrence, metabolism, detoxification, regulations and intake of zearalenone: an oestrogenic mycotoxin.

The spontaneous reaction of atmospheric oxygen with organic compounds leads to a number of degradative changes that reduce the lifetime of many products of interest to the chemical industry, especially polymers, as well as causing the deterioration of lipids in foods. The importance of oxygen in the deterioration of rubber was demonstrated over a century ago,1 and this finding led chemists to investigate the chemistry of oxidative deterioration and its inhibition.

The Mechanism of Antioxidant Action in Vitro

Trichothecene mycotoxins are a group of structurally similar fungal metabolites that are capable of producing a wide range of toxic effects. Deoxynivalenol (DON, vomitoxin), a trichothecene, is prevalent worldwide in crops used for food and feed production, including in Canada and the United States. Although DON is one of the least acutely toxic trichothecenes, it should be treated as an important food safety issue because it is a very common contaminant of grain. This review focuses on the ability of DON to induce toxicologic and immunotoxic effects in a variety of cell systems and animal species. At the cellular level, the main toxic effect is inhibition of protein synthesis via binding to the ribosome. In animals, moderate to low ingestion of toxin can cause a number of as yet poorly defined effects associated with reduced performance and immune function. The main overt effect at low dietary concentrations appears to be a reduction in food consumption (anorexia), while higher doses induce vomiting (emesis). DON is known to alter brain neurochemicals. The serotoninergic system appears to play a role in mediation of the feeding behavior and emetic response. Animals fed low to moderate doses are able to recover from initial weight losses, while higher doses induce more long-term changes in feeding behavior. At low dosages of DON, hematological, clinical, and immunological changes are also transitory and decrease as compensatory/adaptation mechanisms are established. Swine are more sensitive to DON than mice, poultry, and ruminants, in part because of differences in metabolism of DON, with males being more sensitive than females. The capacity of DON to alter normal immune function has been of particular interest. There is extensive evidence that DON can be immunosuppressive or immunostimulatory, depending upon the dose and duration of exposure. While immunosuppression can be explained by the inhibition of translation, immunostimulation can be related to interference with normal regulatory mechanisms. In vivo, DON suppresses normal immune response to pathogens and simultaneously induces autoimmune-like effects which are similar to human immunoglobulin A (IgA) nephropathy. Other effects include superinduction of cytokine production by T helper cells (in vitro) and activation of macrophages and T cells to produce a proinflammatory cytokine wave that is analogous to that found in lipopolysaccharide-induced shock (in vivo). To what extent the elevation of cytokines contributes to metabolic effects such as decreased feed intake remains to be established. Although these effects have been largely characterized in the mouse, several investigations with DON suggest that immunotoxic effects are also likely in domestic animals. Further toxicology studies and an assessment of the potential of DON to be an etiologic agent in human disease are warranted.

Toxicology of deoxynivalenol (vomitoxin).

Biodiesel occupies a prominent position among the alternatives to conventional petrodiesel fuel owing to various technical and economic factors. It is obtained by reacting the parent vegetable oil or fat with an alcohol )transesterification) in the presence of a catalyst to give the corresponding monoalkyl esters, which are defined as biodiesel. Because of the nature of the starting material, the production process, and subsequent handling, various factors can influence biodiesel fuel quality. Fuel quality issues are commonly reflected in the contaminants or other minor components of biodiesel. This work categorizes both the restricted species in biodiesel and the physical properties prescribed by the standards, and details the standard reference methods to determine them as well as other procedures. Other aspects of biodiesel analysis, including production monitoring and assessing biodiesel/petrodiesel blends, are also addressed. The types of analyses include chromatographic, spectroscopic, physical properties-based, and wet chemical methods. The justifications for specifications in standards are also addressed.

Analyzing biodiesel: standards and other methods

The anisidine test, a measure of secondary oxidation products in glyceride oils, was applied to a number of soybean salad oils processed from sound and damaged soybeans. A highly significant correlation (−0.68) was found between the anisidine values of salad oils from sound soybeans and their flavor scores. Multiple correlations between flavor scores, anisidine, and peroxide values yielded a correlation of 0.81 and provided a method for predicting the initial flavor scores of sound soybean salad oils. Similar data for oils from damaged beans gave a highly significant, but lower, correlation (−0.65). Comparative studies indicated that sound crude oils usually contain lower levels of oxidation products than damaged crude. Oxidation in both sound and damaged crudes increased roughly in proportion to iron content. Reproducibility of the test and the effects of hydrogenation, accelerated storage, and fluorescent light on anisidine values were studied. Analysis of damaged oils before and after deodorization showed that little, if any, reduction of anisidine value occurred. Deodorization of sound oils, however, lowered anisidine values. In comparison with damaged oils, the anisidine values of sound oils were lower at comparable stages of processing. The poor quality of damaged soybean oil was substantiated by organoleptic evaluations. Flavor scores of oils given special processing treatments increased as anisidine values decreased.

Oxidation and quality of soybean oil: a preliminary study of the anisidine test

A rapid quantitative capillary gas Chromatographic method has been developed for studying transesterification of soybean oil (SBO) to fatty esters. Standard solutions containing methyl linoleate, mono- , di- and trilinolein were analyzed with a 1.8 m X 0.32 mm SE- 30 fused silica column. The effect of carrier gas flow on reproducibility was determined. Prior to analysis, mono- (MG) and diglycerides (DG) were silylated with N,O- bis(trimethylsilyl) trifluoroacetamide.Tridecanoin was used as an internal standard. From plots of area and weight relationships, slopes and intercepts for all four compound classes were determined. Agreement between the measured and calculated compositions of the standard solutions was good; the overall standard deviation was 0.4. Slopes and intercepts also were determined for SBO and its methyl and butyl esters. Complete separation of ester, MG, DG and triglyceride was obtained in 12 min by temperature programming from 160 to 350 C. This method of analysis gave excellent results when used in a kinetic study of SBO transesterification.

Quantitation in the analysis of transesterified soybean oil by capillary gas chromatography 1

12 corn hybrids (Zea mays L.) were planted in Florida, Georgia, and Tennessee on 2 dates during 1978 to examine the interaction between hybrids, field environments, planting date, and A. flavus infection of developing kernels. At harvest, a broad occcurrence of aflatoxin was observed in the samples, with no significant differences among hybrids. Silk channels of treated ears were inoculated with A. flavus spores; kernels from the inoculated ears exhibited significantly higher levels of toxin than did those of the controls. Insect damage of ears was assessed at harvest by visual examination; a trend of increased toxin levels was associated with greater damage. Presence of bright greenish yellow fluorescence in corn samples was closely linked to the occurrence of high levels of aflatoxin (>300 ng/g), but corn samples with no detectable toxin also routinely exhibited fluorescencing particles.

Aflatoxin contamination of preharvest corn: role of Aspergillus flavus inoculum and insect damage.

A total of 1311 corn samples and 866 soybean samples, including samples from all grades and 2 different crop years, 1964 and 1965, were assayed for the presence of aflatoxin. Samples were extracted by the procedure used in the survey of wheat, grain sorghum and oat samples, and extracts were tested for the presence of aflatoxin by thin-layer chromatography (TLC). The sensitivity limit of the analysis as carried out was 2-5 parts/billion of the metabolite. Of the 35 corn samples that were positive by TLC, 30 gave aflatoxin like responses in ducklings. 5 of these were in grade 5, and 25 were in sample grade. 2 of the 866 soybean samples tested contained aflatoxin by TLC and the duckling test. These were in sample grade. [See preceding abstr.]

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Survey of cereal grains and soybeans for the presence of aflatoxin.2. Corn and soybeans.

SUMMARY Since aflatoxin is formed in corn in the field before harvest, our objectives were to determine at harvest (a) the amount of Aspergillus flavusinfected corn kernels, (b) the amount of A. flavus spores on the surface of corn, (c) the total amount of fungus-infected kernels, (d) the occurrence of A flavus spores in and on insects from corn reported in the first paper of this series, and (e) the correlation between A. flavus infection and occurrence of aflatoxin. The corn was collected at harvest from seven counties in northeastern South Carolina and dried to less than 13% moisture as quickly as possible. Of the 152 aflatoxin-positive samples, 120 showed one or more kernels internally infected with A. flavus and of the 145 aflatoxin-negative samples, 59 showed infection. Of the 297 samples examined, 276 had one or more kernels with surface contamination of A. flavus spores, and in 75 of the samples every kernel was contaminated. When kernels were surface disinfected, 224 samples (50 kernels each) showed 100% internal mold contamination. One or more kernels of 185 samples were infected with A. flavus; this number represents 60% of the total samples. Of the 375 insects collected and examined for A. flavus from the corn samples, 247 showed A. flavus present. Of the 85 rice weevils, 78 were carrying A. flavus spores and of the other 290 insects, 165 were contaminated. Besides A. flavus, the predominant infecting fungi internally were two species of Penicillium and Fusarium. Members of the Mucorales were rarely seen. The occurrence of Aspergillus flavus Link ex Fries and A. parasiticus Speare growing on corn plants in the field before harvest has rarely been recorded (Taubenhaus, 1920). From 0.02 to 0.09% infection of corn kernels before harvest was reported by Tuite (1961) from Indiana. The highest single instance had a 22% infection by A. flavus. In 1970, Tuite and Caldwell (1971) found an average incidence of 0.4% kernel infection before harvest in corn also in Indiana. The A. flavus incidence in southern Indiana counties was 1.2% as compared to 0.2% in northern counties. Rambo et al. (1974) reported a 0.03 to 0.08% incidence of

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W. F. Kwolek

Papers

Oxidation and quality of soybean oil: a preliminary study of the anisidine test

Quantitation in the analysis of transesterified soybean oil by capillary gas chromatography 1

Aflatoxin contamination of preharvest corn: role of Aspergillus flavus inoculum and insect damage.

Survey of cereal grains and soybeans for the presence of aflatoxin.2. Corn and soybeans.

Aflatoxin Occurrence in 1973 Corn at Harvest. II. Mycological Studies