Levels of aflatoxins

In a clinical trial performed in China, the administration of 300 mg/day of copper chlorophyllin to humans who had detectable levels of serum aflatoxin due to unavoidable food contamination resnlted in a 50% reduction of median urinary levels of aflatoxin-DNA adducts. If health benefits from consuming natural chlorophylls were confirmed, it wonld be easy to add green leafy vegetables to a daily diet to obtain the benefit. Since leafy vegetables contain usually up to 200 mg chloro-phylls/100 g fresh weight, the intake of approximately 1 to 2 cups of raw spinach/day... 

Soil populations and aflatoxin contamination are influenced by weather patterns, with hot dry soils favoring the Aspergillus section Flavi. In terms of geographic location, A. flavus incidence is correlated with high minimum temperatures and inversely correlated to latitude. For example, corn ears that develop at temperatures of 28 to 32°C are far more likely to be contaminated by aflatoxin than ears grown later in the season at lower temperatures. However, late planting is not economically feasible due to lower crop yields. Besides hot dry weather, the level of insect and rodent activity in an area may also substantially favor colonization and aflatoxin production. Plant fertility, density, and disease also play roles in the level of aflatoxin contamination. 

Wogan GN, Paglialunga S, Newbeme PM. 1974. Carcinogenic effects of low dietary levels of Aflatoxin B in rats. Food Cosmet. Toxicol. 12 681—85... 

In some modern instruments, a variation of this procedure is used to determine if an analyte concentration exceeds or is less than some threshold level. Feature 8-2 gives an example of how such a comparator can be used to determine whether the level of aflatoxin in a sample exceeds the level that would indicate a toxic situation. The exact concentration of aflatoxin is not needed only an indieation that the threshold has been exceeded is necessary. Alternatively, a simple eomparison with several standards can be used to indicate the approximate concentration of the analyte. 

Statutory provisions requiring a balancing of safety/risk against other considerations have existed for many years. Section 406 of the FD C Act, for example, has provided since 1938 that FDA may establish tolerances for poisonous or deleterious substances, that would otherwise be banned, if those substances are required in the production of food or are unavoidable under good manufacturing practices. It is this provision under which FDA has established a permissible level of aflatoxin in peanuts, corn, milk, and other agricultural commodities.(33)... 

The levels of aflatoxin in food samples consumed during the outbreak ranged between 2.5 and 15.6 microgram/g. Anywhere between 2 and 6 mg of aflatoxin seems to have been consumed daily by the affected people for many weeks. In contrast, analysis of corn samples from the same areas the following year (1975) revealed very low levels of aflatoxin (i.e. less than 0.1 microgram/g), and this may have explained the absence of any reoccurrence of the outbreak in 1975. A ten-year follow-up of fhe epidemic found the survivors fully recovered with no ill effects from the experience. 

An extensive investigation of the outbreak was performed. Aflatoxin levels in foods were measured and showed high levels of aflatoxin B1 and B2. For example, maize grains from the two homes where severe and fatal illness had occurred contained 12 mg/kg and 3.2 mg/kg of aflatoxin Bl, while maize from unaffected homes had a maximum of 0.5 mg/kg aflatoxin Bl. Liver samples were obtained from two patients at necropsy and these indicated... 

In the United States, the Food and Drug Administration (FDA) regulates the quality of food, including the levels of environmental contaminants. The FDA has established guidelines for the levels of aflatoxins permitted in human foodstuffs and animal feed. The maximum permitted level for human food is 20 parts per billion of total aflatoxins. Higher levels are permissible for feed destined for animal consumption. 

Primary) Acute aflatoxicosis is produced when moderate-to-high levels of aflatoxins are consumed. Specific, acute episodes of disease may include hemorrhage, acute liver damage, edema, alteration in digestion, absorption and/or metabolism of nutrients, and possibly death. 

Table II. Carcinogenic Effects of Dietary Levels of Aflatoxin Bi in Rats...

Screening Methods. Screening to detect resistance in corn to kernel infection by A. flavus and/or aflatoxin production have been conducted in the field and to a lesser extent in the laboratory (6). To date, screening for genotypic differences has focused primarily on level of aflatoxin production rather than on frequency of kernel infection. Inoculation methods have generally included some form of wounding of the kernels to establish the... 

Pilot human dosimetry studies have demonstrated the usefulness of adduct measurements in exposure assessments. Higher adduct levels in heavily exposed coke oven workers compared to those with lower exposures or controls have been reported using USERIA (3 )> ELISA (36) or the P-post1abe1ing assay (41). Tobacco consumption is also positively correlated with adduct formation (49). Chemotherapeutic trials are among the best evidence that adduct levels are related to exposure because in these cases, negative controls are truly negative. The development of immunoassays for cisplatin-DNA adducts by Poirier et a1., have led to internal dosimetry estimates and predictions for prognosis (35). Levels of aflatoxin B -adducts have also been identified in human liver and breast with ELISA (40.871. in serum albumin with RIA (88) and ELISA (38)- Multiple adduct assessments are also feasible (Table III) (89). 

Is depicted the HPLC profile from a naturally contaminated peanut sample. This sample when analyzed contained 943 ppb (ug/kg) total aflatoxins. This chromatogram demonstrates that aflatoxins can be identified without any further deriv-atlzatlon by using a diode array detector after the affinity clean-up procedure and reversed phase HPLC. This detector obtains the spectrum of chromatographic peaks. Since as little as 2 ppb In the diet of rats (2) has been found to produce liver tumors following life time exposure, the levels of aflatoxins in the diets of people eating this level of contaminated foods would be of serious concern. 

In order to test the sensitivity of the duckling bioassay, an experiment was carried out with two-day-old ducklings that were fed for four weeks rations containing known levels of aflatoxin provided from a spiked peanut meal. The levels tested were 0, 25, 50, 100, 200, 300, 400, 600, and 800 ppb B. Each level was... 

Bi) that were found, represented only a small fraction (1-2%) of the ingested dose, the absolute amounts were substantial, in view of the high potency of the af la toxins, and the high susceptibility of the young. In retrospect, it is perhaps not surprising that the milk contained these levels of aflatoxin M, considering the high... 

In order to check suitability and sensitivity of the bioassay method, an experiment was carried out with groups of two-day-old ducklings that were fed known levels of aflatoxin for four weeks. Results of mortality and growth rate as criteria of toxicity were treated statistically. Ducklings livers were also examined for... 

Table 9. Relation of Mortality (% Deaths) in Ducklings to Dose Level of Aflatoxin (ppb in ration) and Time on Level (days) ...

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