Gerald C. Llewellyn

Mycotoxin contamination of spices — An update

Abstract This update reviews studies since 1986 concerned with fungal infestation and mycotoxin occurrence in spices. Mycotoxins continue to pose a health concern via human exposure to contaminated spices. Reports indicated average mold counts in the assorted peppers examined to range from 200 to 3 400 000 mold spores g−1 substrate. Of 49% of A. flavus isolates found to be toxigenic, 79% produced aflatoxin B1 (AFB1). Another investigation found AFB1 levels in Coriander sativum in excess of 75 ppb. A sampling of commercial spices in Thailand revealed that 18% of samples of herbs and spices were contaminated with AFB1 (range 40–160 ppb). Among inhibitory ‘essential oils’ from several spices more resistant to mycotoxins, thymol isolated from thyme leaves was shown to inhibit both mycelial growth and aflatoxin production. Substantial reductions in fungal counts and near complete decomposition of AFB1 by irradiation have also been reported. Key future studies may explore irradiation methods, genetic engineering aimed at improving resistance to moulds, and limiting factors which allow mycotoxin production.

Reducing Exposures to Airborne Lead in a Covered, Outdoor Firing Range by Using Totally Copper-Jacketed Bullets

A study was conducted to evaluate the feasibility of reducing or eliminating airborne lead concentrations at a covered, outdoor firing range by using totally copper-jacketed ammunition. Used in the study were 38-caliber-special police revolvers, and firings were conducted with 38-caliber, totally copper-jacketed bullets. The mean lead levels in general area air samples and personal breathing zone samples were 9.53 micrograms/m3 and 5.88 micrograms/m3, respectively, calculated as an 8-hr, time-weighted average (TWA). The mean copper levels in general area samples and personal breathing zone samples were 0.8 micrograms/m3 and 1.43 micrograms/m3, respectively. These concentrations in general area air samples and personal breathing zone samples were well below the current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for occupational exposure to inorganic lead (50 micrograms/m3) and for copper (100 micrograms/m3). No significant difference was found between blood lead levels before and after firing totally copper-jacketed bullets. Based on comparison with results from a comparable study using nonjacketed lead ammunition, it was concluded that the use of totally copper-jacketed bullets significantly reduced airborne lead levels by a factor of 21 in the personal breathing zone samples and by a factor of 7.5 in the general area air samples.

Toxic responses of developing fifth instar milkweed bugs, Oncopeltus fasciatus (Hemiptera), to aflatoxin B1.

Although studies on the aflatoxins have involved test systems ranging from cell cultures to laboratory animals, there appears to be a general lack of information on the ecological and economic effects of aflatoxins on insects. However, this situation is gradually changing. These studies involved the toxic responses of fifth instar milkweed bugs (Oncopeltus fasciatus) to AFB/sub 1/. Milkweed bugs pass through five distinct nymphal instars. In the fifth instar stage, the insect is marked with lateral spots on all of the abdominal pleurites and median spots on the fifth, sixth, seventh, eighth, and ninth dorsal abdominal tergites. The apex of the ventral abdominal surface is black and the remainder of the body is reddish-orange. Also, the adult is elongate to oval, and it is black and red in color. Because of this insects ability to live and reproduce normally when provided dried sunflower seeds and water, it is a very desirable model to study through out the year. It is thought that juvenile insect stages are more sensitive to AFT than are adults, thus the instar and its developmental and sexual responses to aflatoxins are of interest.

Alteration of some toxic aflatoxin responses in Syrian hamsters fed zinc carbonate-supplemented diets

SummaryChronic exposure to aflatoxins (AFTs) below the LD50 can result in reduced weight gain, hepatocellular necrosis and bile duct cell proliferation. Here, we report whether dietary zinc (Zn2+) protects against both aflatoxicosis and precancer in male weanling hamsters fed either 14.6 mg/kg AFTs, 3000 mg/kg zinc carbonate, or both for 17 weeks. The AFTs (either alone or with Zn2+) reduced weight gains but not feed consumption. Whereas controls possessed 172.7±21.7 mg/100 ml plasma glucose, the AFTs and Zn2+ groups had 132.1±19.5 and 122.7 mg/100 ml, respectively. For plasma cholesterol, the AFTs plus Zn2+ groups was 26.5±4.3 compared to 32.3±3.0, 31.5±4.8 and 36.0±2.1 mg/100 ml for control, Zn2+ and AFTs groups, respectively. The latter exhibited bile duct cell hyperplasia, focal liver necrosis and hemorrhage but the AFTs plus Zn2+ groups livers had less damage. Meglahepatocytes indicated precancerous changes. These data suggest a trend toward Zn2+-induced reduction for AFTs-promoted liver damage.

Reduced aflatoxicosis in livers of hamsters fed a manganese sulfate supplement

Male, weanling Syrian hamsters (Mesocricetus auratus) were given (for 10 weeks) diets supplemented with manganese sulfate, aflatoxin, or a combination of both. All animals were killed and a histopathologic evaluation was performed on each liver to assess the influence of a manganese-supplemented diet on aflatoxicosis. Serum cholesterol and liver glycogen levels were also analyzed to further study the interaction of manganese and aflatoxin. Characteristic aflatoxin-induced precancerous histopathologic changes were observed in animals receiving the toxin. These changes included bile duct cell hyperplasia, enlarged nuclei, nuclear inclusions, and megala-hepatocytes. The dietary manganese addition to aflatoxin animals caused a slight reduction in the bile duct cell hyperplasia and significantly reduced the enlarged nuclei and nuclear inclusions. The latter indicates that the manganese may be influencing membrane chemistry. Animals receiving aflatoxin alone showed significantly increased serum cholesterol and liver glycogen. The cholesterol levels were significantly increased over the aflatoxin-induced levels when manganese was given in combination with the aflatoxin. The manganese lowered the increased liver glycogen levels caused by the aflatoxin. Dietary manganese shows some potential in suppressing several, but not all, of the aspects of developing aflatoxicosis in the hamster. The specific mode and site of action of manganese requires additional study.

In Vitro Growth of Coriolus Versicolor, a Wood-Decay Fungus, Responds Differentially to Catechol and Tannic Acid

Both decay and disease of trees are of great economic importance to the commercial wood products industry. Certain micro-organisms such as the white-rot fungi can literally live upon wood via their abilities to secrete cellulolytic and ligninolytic enzymes (Highley and Kirk, 1979). The capacity of white-rot fungi to degrade lignin involves in part their elaboration of an extra-cellular polyphenol oxidase (Agrios,.1978; Highley and Kirk, 1979; Nobles, 1958, 1965).

Ultrastructure of the wood-decay fungus, Coriolus versicolor, in relation to a catechol-induced bimodal growth response

Abstract The growth of the white-rot fungus, Coriolus versicolor, can be impaired by polyphenols which accumulate as a host-response to infection and/or injury. Polyphenol detoxification can be regulated by polyphenol oxidase which can be secreted by C. versicolor. To assess the role of polyphenols in the growth of C. versicolor in culture, both catechol (CT) and malt extract (ME) were

Differential changes in rat brain tryptophan, serotonin and tyrosine levels following acute aflatoxin B1 treatment

Female Sprague-Dawley rats were treated acutely (12-h) with aflatoxin B1 (100 micrograms/kg i.p.) or vehicle (10% acetone in 0.9% NaCl) and regional brain levels of tryptophan, serotonin and tyrosine were assayed. Brainstem but not cerebellar or cortical tyrosine levels were decreased in aflatoxin B1-treated rats. Brain tryptophan was increased in all 3 brain regions by acute aflatoxin B1 treatment, while serotonin levels were unaltered in the cerebellum and cortex and decreased in the brainstem. These experiments indicate that acute aflatoxin B1 treatment differentially alters brain amino acids and serotonin and that changes in brain tryptophan, the serotonin precursor, do not parallel changes in brain serotonin.

Overexposures to lead at a covered outdoor firing range

Significant overexposures to airborne lead were found in a covered, outdoor firing range among seven cadets during firing of conventional, nonjacketed, lead bullets. The mean lead concentrations in general area air samples and personal-breathing-zone air samples were 68.36 μg/m3 and 128.46 μg/m3, respectively, calculated as an 8h, time-weighted average (TWA). Eight (44%) of 18 area air samples, taken as far as 50 yards from the firing line, and 10 (67%) of 15 personal breathing zone air samples exceeded the current Occupational Safety and Health Administration (OSHA) standard for occupational exposure to airborne lead (50μg/m3). Blood lead levels (using a t-test) were found to increase significantly in all cadets after day 2 (p < 0.0001) and day 5 (p < 0.0007) of firing conventional, nonjacketed, lead bullets. None of the blood level values exceeded the OSHA standard of 40 μg/dl. A strong positive correlation (r = 0.92; p < 0.000001) existed between personal-breathing-zone air lead levels and the number of rounds fired by the cadets. A positive correlation also existed between blood lead levels and cumulative personal breathing zone air lead levels (r = 0.85; p < 0.02), as well as the total number of rounds fired (r = 0.84; p < 0.02). Based on environmental and medical data, it was concluded that a potential health hazard may exist due to inorganic lead exposure to cadets at this covered outdoor range during firing exercises.

Aflatoxin Occurrence in Virginia Price Support-Corn: 1986 Crop-Year

Aflatoxins (AFTs), as representatives from a group of secondary fungal metabolites known as mycotoxins, are divided into several subgroups based on differing chemical characteristics (Figure 1). As a by-product of their metabolism, Aspergillus flavus and A. parasiticus produce AFTs including aflatoxin B1 (AFB1), aflatoxin B2 (AFB2 ), aflatoxin G1 (AFG1 ), and aflatoxin G2 (AFG2 ). Collectively, the aflatoxins are among the most toxic hepatocarcinogens known (Sporn, 1966).