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Behavioral response in the terrestrial isopod Porcellio scaber (Crustacea) offered a choice of uncontaminated and cadmium-contaminated food.

The objective of this study was to find out whether Porcellio scaber discriminates against Cd-contaminated food. The foraging behavior in animals offered uncontaminated and Cd-contaminated food simultaneously was quantified for 48-h employing computer-aided video tracking. To see whether the isopods' selection of less contaminated food could diminish the influence Cd on food consumption, growth, metal assimilation, moulting and mortality, Cd-dosed food (20, 45, 200 and 450 mg kg(-1) dry weight) was offered together with untreated food for 3 weeks. Data from the video tracking experiments revealed that animals visited Cd-dosed food as often as untreated food, but spent much less time near Cd-dosed food. Discrimination against Cd-contaminated food increased with previous experience with contaminated food and/or with increased Cd body burden. In 3 weeks exposure uncontaminated food preference rose with time of exposure and cadmium concentration in food and reached a maximal preference ratio of 65% (untreated food): 35% (Cd-dosed food). The decreased consumption of Cd-dosed food was compensated by the increased consumption of control food. Cadmium body burden increased with time of exposure and cadmium concentration in food consumed, while the influence of Cd on food consumption, growth and moulting was diminished.

Animal Feed↗

Comparison of modified immunodiffusion and Bacteriological Analytical Manual (BAM) methods for detection of Salmonella in raw flesh and highly contaminated food types.

A wide variety of naturally contaminated and inoculated raw flesh and highly contaminated food types was analyzed by a modified immunodiffusion enrichment protocol and the Bacteriological Analytical Manual (BAM) method to determine the equivalence of these methods. This modification was developed by Agriculture Canada to allow addition of a high-temperature selective enrichment step in tetrathionate brilliant green broth at 42 degrees C while maintaining a 2-day total test time. Foods representing red meat, white meat, frog, and seafoods and one type of animal meal were evaluated. A total of 320 samples was tested, resulting in false negative rates of 5.2 and 3.5%, respectively, for the modified immunodiffusion and the BAM culture methods. The overall agreement rate was 96.9%.

Animals↗

Occurrence of nitroso compounds in fungi-contaminated foods: a review.

Dimethylnitrosamine (NDMA), diethylnitrosamine (NDEA), methylbenzylnitrosamine, and a new N-nitroso compound, N-3-methylbutyl-N-1-methylacetonylnitrosamine (NMAMBA), were found in cornbread that was inoculated with Fusarium moniliforme and underwent an incubation and the addition of a small amount of NaNO2. The carcinogenicity of NMAMBA was shown by the induction of forestomach carcinomas and liver tumors in mice and rats. Another new nitrosamine, N-2-methylpropyl-N-methylacetonyl nitrosamine, was isolated in millet and wheat flour after similar treatment. Some species of fungi not only can reduce nitrates to nitrites but also can increase the amount of secondary amines in the moldy foods and provide favorable conditions for the synthesis of nitrosamines. Some fungi may utilize primary amines to synthesize nitrosamines in appropriate culture mediums. Furthermore, the cornmeal may naturally contain trace amounts of nitrosamines, as detected by a gas chromatography/thermoenergy analyzer. Prolonged feeding of F. moniliforme-inoculated cornbread alone also induced the development of forestomach carcinoma in rats. This indicates the occurrence of potential carcinogens, perhaps certain Fusarium mycotoxins, in the moldy cornbread in addition to the carcinogenic nitrosamines. Another nitroso compound, Roussin red methylester (di-mu-methanethiolatotetranitrosodiiron) was found in pickled vegetables that are eaten daily in the Linxian (China) area. Roussin Red may provide NO-2 ions, which would react readily with secondary amines to form nitrosamines. Possibly this compound is a natural tumor promoter and is able to induce epithelial hyperplasia of the upper digestive tract and forestomach papilloma in treated mice. Also, trace amounts of NDMA, NDEA, and some other nitrosamines were found in the extract of pickled vegetables.

Animals↗

Comparison of bacterial counts obtained from naturally contaminated foods by means of Stomacher and blender.

Four Regional Health Protection Branch laboratories each compared aerobic colony counts obtained after "stomaching" and blending, for a minimum of 10 samples in each of the seven food groups: dry pastas; chocolate and cocoa powders; frozen entrees (macaroni and cheese, chow mein, chop suey, fried rice, seafood casseroles, and Salisbury steak); nonfat dry milk; shrimp and crabmeats; spices; and breakfast sausages. Overall, counts obtained after using the Stomacher were equivalent to or higher than counts obtained after using the blender in 73% of the comparisons (alpha = 0.05). Where differences existed, counts obtained after using the Stomacher tended to be higher than counts obtained after using the blender from milk powder and lower from sausage. Aerobic colony counts from these foods are not unacceptably biased when obtained by Stomacher.

Aerobiosis↗

Internal exposure from the ingestion of foods contaminated by 137Cs after the Chernobyl accident. Report 1. General model: ingestion doses and countermeasure effectiveness for the adults of Rovno Oblast of Ukraine.

The Chernobyl accident, which occurred in April 1986, resulted in the atmospheric release of about 70--100 PBq of 137Cs. This paper examines the doses to the adult population of the northern part of Rovno Oblast, Ukraine, from ingestion of 137Cs. Fallout of 137Cs in these regions was lower than in other regions of Ukraine. However, the transfer of 137Cs from soil to milk in the region considered is high (up to 20 Bq L-1 per kBq m-2) and results in the predominance of internal doses compared to those from external exposure. Numerous measurements of 137Cs soil deposition, 137Cs milk contamination, and 137Cs body burden have been made in the area and form the basis of a general model of internal exposure from the ingestion of foods contaminated by 137Cs. This paper has two main purposes. The first is to develop the general phenomenological description of the process leading to internal exposure from the ingestion of 137Cs contaminated foods in the situation where different countermeasures are realized. The second is to apply the model for the adult population of the northern part of the Rovno Oblast (first report) for the limited time period of up to six years after the accident. The doses actually received by the adults are estimated to be four to eight times smaller than the doses calculated for the situation without countermeasures.

Adult↗

Random amplification of polymorphic bacterial DNA: evaluation of 11 oligonucleotides and application to food contaminated with Listeria monocytogenes.

The polymerase chain reaction was used to obtain randomly-amplified polymorphic DNA (RAPD) profiles from Listeria spp. and enterobacteria. Eleven different oligonucleotides were evaluated. Only one, HR4 (19mer), generated reproducible and specific profiles for Listeria spp., while results for enterobacteria were controversial. A total of 57 different Listeria strains were subjected to the RAPD analysis and 27 different profiles were recognized. RAPD typing allowed strains of the same serotype to be distinguished but the same profile was obtained from different serotypes of L. monocytogenes in three cases and in one case two different serotypes of L. innocua yielded the same profile. RAPD-typing with HR4 allowed L. monocytogenes contamination in several food outlets to be traced back to a food processing plant. In additional experiments, the general utility of this RAPD system in typing Yersinia enterocolitica, verotoxigenic Escherichia coli and Salmonella enteritidis was evaluated.

Bacterial Typing Techniques↗

Relative effectiveness of selenite cystine broth, tetrathionate broth, and rappaport-vassiliadis medium for recovery of Salmonella spp. from raw flesh, highly contaminated foods, and poultry feed: collaborative study.

A collaborative study was performed in 18 laboratories to validate use of Rappaport-Vassiliadis (RV) medium in the standard culture method for recovery of Salmonella spp. from raw, highly contaminated foods and poultry feed. RV medium made from its individual ingredients and incubated at 42 degrees C was compared with selenite cystine (SC) broth incubated at 35 degrees C and tetrathionate (TT) broth incubated at 35 degrees and 43 degrees C for effectiveness in recovery of Salmonella spp. Four artificially contaminated foods (oysters, frog legs, mushrooms, and shrimp) and poultry feed and one naturally contaminated food (chicken) were analyzed. The artificially contaminated foods were inoculated with single serovars of Salmonella at target levels of 0.04 colony-forming units (CFU)/g for the low level and 0.4 CFU/g for the high level. For analysis of 1125 test portions, RV medium (42 degrees C) recovered Salmonella from 409 test portions; TT (43 degrees C), from 368 test portions; TT (35 degrees C), from 310 test portions; and SC (35 degrees C), from 334 test portions. Overall, RV medium was comparable with or better than other selective enrichments for recovery of Salmonella from the foods in this study, except mushrooms. From mushrooms, SC broth (35 degrees C) recovered more positive test portions than did RV medium (42 degrees C) and TT broth (43 degrees C). The method for detection of Salmonella in raw, highly contaminated foods and poultry feed using RV medium has been adopted by AOAC INTERNATIONAL. AOAC Official Method 967.25, Salmonella in Foods, Preparation of Culture Media and Reagents, has been revised to include RV medium, and the applicability of AOAC Official Method 967.26, Salmonella in Foods, Detection, has been restricted to processed foods.

Animal Feed↗

Evaluation of certain food contaminants.

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food contaminants, with the aim to advise on risk management options for the purpose of public health protection. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of contaminants and assessments of intake. A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food contaminants (acrylamide, ethyl carbamate, inorganic tin, polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons). Cadmium was assessed to determine the impact of different maximum limits on intake. Annexed to the report are tables summarizing the Committee's recommendations for intakes and toxicological evaluations of the food contaminants considered, and a description of the statistical methods for dose-response modelling as applied at this meeting.

Consumer Product Safety↗

Birthweight in a fishing community: significance of essential fatty acids and marine food contaminants.

BACKGROUND: Marine food provides essential fatty acids that are important during pregnancy, but the benefits may be limited at high intakes and by seafood contaminants. METHODS: In the fishing community of the Faroe Islands, 182 pregnant women with spontaneous singleton births were consecutively recruited for a cohort in 1994- 1995. Concentrations of fatty acids and seafood contaminants in blood samples were analysed as predictors of gestational length and birthweight. RESULTS: Serum concentrations of eicosapentaenoic acid (EPA) increased with maternal marine food intake, while the tendency was less clear for docosahexaenoic acid (DHA). An increase in the relative concentration of DHA in cord serum phospholipids by 1% was associated with an increased duration of gestation by 1.5 days (95% CI : 0.7-2.2). However, birthweight adjusted for gestational length decreased by 246 g (95% CI : 16-476) for each increase by 1% of the EPA concentration in cord serum. Concentrations of the seafood pollutants mercury and polychlorinated biphenyls (PCB) were associated with fatty acids levels, but the contaminants did not appear to affect any of the outcome parameters. CONCLUSION: An increased intake of marine fats appears to prolong the duration of gestation, but birthweight adjusted for gestational age may decrease at high intake levels. This effect does not seem to be due to increased exposures to seafood contaminants.

Birth Weight↗

Food contamination with organic materials in perspective: packaging materials as the largest and least controlled source? A view focusing on the European situation.

The comparison of the various sources of food contamination with organic chemicals suggests that in the public, but also among experts, the perception of risk is often distorted. Firstly, neither pesticides nor environmental pollutants contribute the most; the amount of material migrating from food packaging into food may well be 100 times higher. Secondly, control of these large migrants is often lagging behind the standards set up for other sources, since many of the components (particularly those not being "starting materials") have not been identified and, thus, not toxicologically evaluated. Finally, attitudes towards different types of food contaminants are divergent, also reflected by the legal measures: for most sources of food contamination there are strict rules calling for minimization, whereas the European packaging industry has even requested a further increase in the tolerance to as close as possible to the limit set by the toxicologists. This paper calls for a more realistic perception and more coherent legal measures-and improvements in the control of migration from packaging material.

Europe↗

Induction and inhibition of cytochrome P450 isoforms by imazalil, a food contaminant, in mouse small intestine and liver.

1. The effects of imazalil, a food contaminant used as a fungicide, were investigated on the expression and activity of cytochrome P450 in the small intestinal mucosa and liver of mice. Imazalil was orally administered to mice daily at 1 or 10 mg/kg for 3 days. 2. Imazalil enhanced cytochrome P450-catalysed ethoxyresorufin O-deethylase and pentoxyresorufin O-depentylase (PROD) activities in both tissue microsomes at the 10 mg/kg/day dose level, indicating the induction of cytochrome P450 subfamilies CYP1A and CYP2B. In addition, immunochemical analyses also demonstrated an enhanced expression of CYP2B, CYP2C and CYP3A subfamilies in both tissues. 3. Imazalil was a potent inhibitor of cytochrome P450-dependent monooxygenase activities (PROD, aminopyrine N-demethylase and erythromycin demethylase) in in vitro assays using both small intestinal and liver microsomes. 4. From these findings, imazalil has been demonstrated to have not only a potent inhibitory activity but also a significant inducing ability of P450 isoforms in the small intestine. Prolonged ingestion of such a food contaminant may modulate the xenobiotic-metabolizing enzyme system at the site of a primary portal of xenobiotic entry to the systemic circulation.

Animals↗

Effects of pentachlorophenol-contaminated food organisms on toxicity and bioaccumulation in the frog Xenopus laevis.

Sub-adult African clawed frogs (Xenopus laevis) were fed pentachlorophenol (PCP)-injected mealworms containing 64.8 to 2604 ug of PCP per gram of worm for 27 days. There was no mortality and no significant bioaccumulation of PCP in the frogs. After three weeks, frogs fed 2,604 micrograms/g of PCP ceased eating. The no observed adverse effects level (NOAEL) based on significantly reduced food consumption (PCP-injected mealworms) was 638 micrograms/g. This corresponded to a NOAEL based on PCP intake of about 8 micrograms PCP/g frog/day. A toxicity threshold model estimated that about 800 micrograms/L of waterborne PCP may be a threshold for adverse effects in Xenopus or similar amphibians. Further study is needed to verify threshold estimates.

Animals↗