This study was undertaken to relate quantitatively the aflatoxin residue found in eggs and tissues to the aflatoxin intake via feed. Eighteen hens were fed an aflatoxin B1 (B1)-contaminated feed (8 micrograms/g) for 7 days, after which half the group was sacrificed; the remainder were sacrificed after an additional 7 days on an aflatoxin-free diet. Eggs were collected over the entire 14-day period. Aflatoxicol (R0), B1, or both were found in eggs and tissues (kidneys, liver, muscle, blood, and ova). Aflatoxin M1 (M1) (.04 to .1 ng/g) was found only in the kidneys. Levels of R0 and B1 were approximately the same in eggs, ova, kidneys, and liver. In eggs, the levels of R0 and B1 (.02 to .2 ng/g) increased steadily for 4 or 5 days, after which time the levels plateaued and then decreased after B1 withdrawal at the same rate as they had increased. At 7 days after withdrawal, only trace amounts of R0 (.01 ng/g) remained in eggs. All tissues, except blood, from hens sacrificed immediately before aflatoxin withdrawal contained R0 (.04 to .4 ng/g) or R0 and B1 (.04 to .8 ng/g). The R0 (.03 to .11 ng/g) was the only aflatoxin detected in muscle, and B1 (.05 to .07 ng/g) was the only aflatoxin in blood. Seven days after aflatoxin withdrawal, B1 (.08 ng/g) was found in one of nine livers and R0 (.01 to .04 ng/g) in eight of nine muscles analyzed, but no aflatoxins were found in any other tissues.
Ochratoxin A (OA) is a nephrotoxic and nephrocarcinogenic mycotoxin produced by Aspergillus and Penicillium species. It has been found mainly in cereal grains and coffee beans. The purpose of this study was to investigate the occurrence of OA in cereal grains and in coffee imported to the United States. A modified liquid chromatographic (LC) method for determining OA in green coffee was applied to wheat, barley, green coffee, and roasted coffee. The test sample was extracted with methanol–1% NaHCO3 (7 + 3), and the extract was filtered. The filtrate was diluted with phosphate-buffered saline (PBS), filtered, and passed through an immunoaffinity column. After the column was washed with PBS and then with water, OA was eluted with methanol. The eluate was evaporated to dryness, and the residue was dissolved in acetonitrile–water (1 +1). OA was separated on a reversed-phase C18 LC column with acetonitrile-water-acetic acid (55 + 45 + 1) as eluant and quantitated with a fluorescence detector. Recoveries of OA from the 4 commodities spiked over the range 1–4 ng/g were 71–96%. The limit of detection was about 0.03 ng/g. OA contamination at >0.03 ng/g was found in 56 of 383 wheat samples, 11 of 103 barley samples, 9 of 19 green coffee samples, and 9 of 13 roasted coffee samples. None of the coffee samples contained OA at >5 ng/g; only 4 samples of wheat and 1 sample of barley were contaminated above this level.
The behavior of microorganisms was studied in mung beans and alfalfa seeds before and after germination in modified, commercially available bean-sprouting kits. The microorganisms were enumerated by the aerobic plate count (APC) and by total yeast and mold count procedures. Salmonella species were artificially inoculated into selected samples and were enumerated by the most probable number (MPN) method. After germination of the beans or seeds into mature sprouts, significant increases were noted in APCs and in MPN values of Salmonella species. Although counts of yeasts and molds did not increase significantly after germination, these samples showed an increase in toxic Aspergillus flavus and potentially toxic Alternaria species. The presence of toxic Penicillium cyclopium molds also increased substantially in 5 samples of a single brand of mung beans. Analysis of selected sprout samples, however, showed no presence of aflatoxin.
Ninety-five isolates of Aspergillus and Penicillium species from selected dried foods were examined for their ability to produce cyclopiazonic acid (CPA). The isolates were grown in sterile synthetic liquid medium at 28°C for 8 days in the dark. The medium and mold mycelia were then extracted with chloroform. CPA was semiquantitative^ determined by thin layer chromatography through visual comparison with standards. The cultures of A. flavus were also examined for their ability to produce aflatoxin. One A. tamarii and all 13 P. urticae isolates produced CPA, whereas only 19 of the 31 (61%) A. flavus isolates produced CPA, and 6 (19%) A. flavus produced aflatoxin. All 13 P. urticae isolates also produced patulin and griseofulvin. CPA-producing A. flavus was found in all food types but not in all samples. CPA-producing P. urticae was found only in dried beans and macaroni.
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