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.
The mold flora of 944 green coffee bean samples from 31 coffee-producing countries was determined before and after surface disinfection with 5% NaOCl. Molds were detected on 99.1 % of 47,200 beans not surface-disinfected and in 47.9% of 47,200 disinfected beans. Although the percentage of differences in occurrence of mold before disinfection was minimal (93.4 to 100%) on a country-by-country basis, after disinfection the beans from Asiatic and African countries showed more internal invasion (80.5%) than those from Central and South America (49.4%). Aspergillus spp., which dominated the mold flora of 944 samples before and after disinfection, included the toxigenic A. ochraceus, A. flavus and A. versicolor as well as A. niger, A. tamarii, A. wentii and species of the A. glaucus group. The genus Penicillium, including the toxigenic P. cyclopium, P. citrinum and P. expansum, was detected regularly, although its occurrence was substantially lower than that of the aspergilli, especially after surface disinfection. The rare detection of Alternaria and Fusarium indicated that toxigenic species of these genera do not readily invade green coffee beans. A. flavus and A. tamarii were prevalent in Central and South American beans, whereas other aspergilli were prevalent in Asiatic and African beans. The penicillia were prevalent in Central and South American beans.
Migration of Salmonella enteritidis through egg albumen to the yolk and its subsequent growth in the yolk were examined. Submersion of eggs in .1% mercuric chloride solution for 1 h followed by submersion in 70% ethanol for 30 min resulted in an eggshell surface from which no Salmonella organisms were recovered. The eggs were then inoculated with S. enteritidis under the shell membrane. Although growth of S. enteritidis was negligible in eggs refrigerated up to 16 days, the population level of the organism increased by more than 8 log10 units in unrefrigerated eggs stored for the same amount of time.
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.
The mold flora was determined for 146 samples of fresh but visibly moldy tomatoes collected from sorting belts in tomato catsup processing plants in California and in Midwestern and Eastern United States. Mold found in 141 of the samples included at least 22 genera, principally Alternaria, Aspergillus, Cladosporium, Fusarium and Penicillium, and 51 species. The California tomatoes were dominated by Geotrichum candidum and species of Aspergillus and Penicillium; Midwest and East tomatoes were dominated by Alternaria. This suggested that the predominant molds in tomatoes may differ, depending on geographical source. Tenuazonic acid (TA), a toxic metabolite of Alternaria spp., was found in 73 of the samples at a range of 0.4 to 69.7 (average 4.94) μg/g of moldy tissue; however, Alternaria spp. were not found in 35 of the 73 TA-positive samples. It is possible that other molds may produce TA or that the toxin-producing Alternaria died off before our sampling.
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