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PubMedDate not supplied

Key elements of food contamination monitoring programmes.

The key elements of programmes for monitoring food contamination are reviewed in relation to their purposes, scope and priorities. Attention is drawn to the requirements and quality assurance of procedures for sampling and analysis, and methods of handling and processing analytical surveillance data. The benefits to be derived from national monitoring programmes are improved food safety, warning of problems of contamination, provision of intake data for evaluation of health hazards, better management and use of natural resources, supply of data on environmental pollution and reliable information on food safety for the public, and provision of a means of checking the effectiveness of regulatory mechanisms and planning technological developments.

Food Contamination↗
PubMed1978

Pesticides and heavy metals as food contaminants.

From the general pollution, contaminants spread along a variety of routes, many of which lead to our food. Pesticides and heavy metals as food contaminants have raised strong public concern and contributed to the general uneasiness associated with the pollution boom of the last two decades. Pesticides in food are predominantly residues from their application on growing crops, less often from post harvest use on stored agriculatural products, whereas heavy metals contaminate the food at various stages along the food production line. Both groups of contaminants exhibit in the number of their members a spectrum of health hazards. A few examples of these will be dealth with, and thought will be given to some features in the philosophies behind the current practices of risk assessment and management in this area. A widespread shortage of toxicological expertice maintain a level of ignorance sufficient to make risk evaluation very often a dilemma. This distressing shortcoming at least partly arises form a common neglect of toxicology as a university discipline. Some international efforts to control food contamination will also be touched upon.

Animals↗
PubMed1994

Contaminated food, a hazard for the very young.

Contaminated food is responsible for much diarrhoeal disease in young children, yet the education of mothers and care-givers about the preparation of food under hygienic conditions tends to be neglected.

Cooking↗
PubMed1991

Food contamination by hydrocarbons from packaging materials determined by coupled LC-GC.

Paraffins from raw extracts of foods and packing materials were isolated by LC and directly transferred to GC, applying concurrent eluent evaporation and a loop-type interface. Paraffins from various packing materials have been characterized: sisal bags, cardboard boxes, plastic films, wax-coated paper and cardboard as well as paraffin coatings. Important food contamination was found for sisal bags, cardboard boxes, and wax-coated paper/cardboard. Contamination by paraffin coatings on cheese was surprisingly small.

Aluminum↗
PubMed2000

Development and evaluation of a PCR-microplate capture hybridization method for direct detection of verotoxigenic Escherichia coli strains in artificially contaminated food samples.

For the purpose of detecting, directly in food, verotoxigenic Escherichia coli, a microplate hybridization method for the detection of PCR products from the SLT I and SLT II genes, was developed and evaluated. Two pairs of primers and two probes, specific for the SLT I gene and for the SLT II gene, were designed and tested. For the strains containing both genes, two PCR products of different molecular weights were obtained, whereas when only one gene was present only one fragment resulted from PCR. The use of the biotin-labeled probes allowed the immobilization of the PCR products in the microtiter plate wells and by this means their detection was possible using an ELISA-based technique. Forty artificially contaminated and fifty naturally contaminated food samples were analyzed by using the PCR-microplate hybridization technique developed in this study. All the artificially contaminated food samples were positive, independently of the number of cells inoculated before the enrichment step, whereas the naturally contaminated food samples were all negative.

Bacterial Toxins↗
PubMed1997

Evaluation of luciferase reporter bacteriophage A511::luxAB for detection of Listeria monocytogenes in contaminated foods.

A511::luxAB is a recombinant derivative of a broad-host-range bacteriophage specific for the genus Listeria, transducing bacterial bioluminescence into infected cells. In this study, we have evaluated its use for rapid and easy testing of contaminated foods and environmental samples for the presence of viable Listeria cells, in comparison to the standard plating procedure. With a short preenrichment step of 20 h, the system was capable of detecting very low initial contamination rates in several foods artificially contaminated with Listeria monocytogenes Scott A cells. In ricotta cheese, chocolate pudding, and cabbage, less than one cell per g of food could be clearly identified by comparing the light emission of phage-infected samples to that of controls without lux phage. In foods having a large and complex microbial background flora, such as minced meat and soft cheese, at least 10 cells per g were necessary to produce a positive bioluminescence signal. Of 348 potentially contaminated natural food and environmental samples, 55 were found to be Listeria positive by the lux phage method. The standard plating procedure detected 57 positive samples. Some differences were observed with respect to the individual samples, i.e., the lux phage procedure detected more positive samples among the dairy products and environmental samples, whereas the plating procedure revealed more contaminated meat and poultry samples. Overall, both methods performed similarly, i.e., were equally sensitive. However, the minimum time required for detection of Listeria with the luciferase phage assay was 24 h, which is much shorter than the 4 days needed by the standard plating method. Furthermore, a most probable number technique with three parallels, based on the use of A511::luxAB for differentiation of positive and negative tubes, is described. The method enables rapid enumeration of low levels of Listeria cells in several foods tested, against the background of a competing microflora.

Animals↗
PubMedDate not supplied

Relative effectiveness of selenite cystine broth, tetrathionate broth, and Rappaport-Vassiliadis medium for the recovery of Salmonella from raw flesh and other highly contaminated foods: precollaborative study.

The effectiveness of selenite cystine (SC) broth, tetrathionate (TT) broth, and Rappaport-Vassiliadis (RV) medium for recovery of Salmonella spp. from 8 highly contaminated foods was determined. RV medium prepared from individual ingredients and incubated at 42 degrees and 43 degrees C was compared with 2 commercial (Difco and Oxoid) media incubated at 42 degrees C. Naturally and artificially contaminated foods were tested under 2 protocols. For Protocol 1, each food was preenriched in the appropriate medium. After incubation, serial 10 fold dilutions of the preenriched foods were inoculated into selective enrichment media and incubated at 35 degrees, 42 degrees, or 43 degrees C. Effectiveness of these conditions was evaluated by most probable number determination of Salmonella spp. recovered. Productivity of selective enrichments did not differ significantly with this protocol, except that with Oxoid RV medium the number of Salmonella cells recovered from most of the foods was significantly reduced. For Protocol 2, twenty 25 g test portions from artificially inoculated foods were examined qualitatively for Salmonella spp. The effectiveness of the broth/temperature combinations was determined by the number of positive tests under each condition. RV medium prepared from individual ingredients and TT broth incubated at 43 degrees C yielded significantly more Salmonella-positive tests from frog legs and lettuce than did SC and TT broths incubated at 35 degrees C or commercial RV medium incubated at 42 degrees C. With pork sausage and ground beef, significantly fewer Salmonella-positive tests were found with Oxoid RV medium incubated at 42 degrees C and SC incubated at 35 degrees C than from other selective enrichments.(ABSTRACT TRUNCATED AT 250 WORDS)

Culture Media↗
PubMed2003

The food contaminants bisphenol A and 4-nonylphenol act as agonists for estrogen receptor alpha in MCF7 breast cancer cells.

Xenoestrogens are chemically distinct industrial products potentially able to disrupt the endocrine system by mimicking the action of endogenous steroid hormones. Among such compounds, the ubiquitous environmental contaminants bisphenol A (BPA) and 4-nonylphenol (NPH) may promote adverse effects in humans triggering estrogenic signals in target tissues. Following a research program on human exposure to endocrine disruptors, we found contamination of fresh food by BPA and NPH. More important, these contaminants were found to display estrogen-like activity using as a model system the estrogen-dependent MCF7 breast cancer cells (MCF7wt); its variant named MCF7SH, which is hormone-independent but still ERalpha-positive, and the steroid receptor-negative human cervical carcinoma HeLa cells. In transfection experiments BPA and NPH activated in a direct manner the endogenous ERalpha in MCF7wt and MCF7SH cells, as the antiestrogen hydroxytamoxifen was able to reverse both responses. Moreover, only the hormone-binding domains of ERalpha and ERbeta expressed by chimeric proteins in HeLa cells were sufficient to elicit the transcriptional activity upon BPA and NPH treatments. Transfecting the same cell line with ERalpha mutants, both contaminants triggered an estrogen-like response. These transactivation properties were interestingly supported in MCF7wt cells by the autoregulation of ERalpha which was assessed by RT-PCR for the mRNA evaluation and by immunoblotting and immunocytochemistry for the determination of protein levels. The ability of BPA and NPH to modulate gene expression was further confirmed by the upregulation of an estrogen target gene like pS2. As a biological counterpart, concentrations of xenoestrogens eliciting transcriptional activity were able to stimulate the proliferation of MCF7wt and MCFSH cells. Only NPH at a dose likely too high to be of any physiological relevance induced a severe cytotoxicity in an ERalpha-independent manner as ascertained in HeLa cells. The estrogenic effects of such industrial agents together with an increasing widespread human exposure should be taken into account for the potential influence also on hormone-dependent breast cancer disease.

Benzhydryl Compounds↗
PubMed1981

Distinguishing common food-contaminating bat hairs from certain feather barbules.

Differences are described between common food-contaminating vespertilionid bat hairs (Chiroptera: Vespertilionidae) and similar-appearing downy feather barbules of passeriform birds, including cuticular scales, pigment distribution, and basal characteristics. Fifteen imported food samples analyzed over a 1 1/2 year period were contaminated with these bat hairs.

Animals↗
PubMed1988

[Residues of active substances after consumption of contaminated food: status report on the evaluation of residues with examples of two drugs].

Pharmacokinetic models are presented for the computation of time courses of blood levels of drugs in man following the consumption of contaminated food. Mathematically, two linear systems of differential equations are set up for the donor organism (e.g., trout) and for the recipient, (e.g., man), where the first system generates the initial conditions for the second. Models of this kind are applied to the transfer of chloramphenicol to man via carp and trout (which had previously been administered this drug) and to the transfer of theophylline to infants via breast milk. Limiting concentration profiles are computed by constructing the most favourable and most adverse combinations of parameters with respect to drug elimination in both the donor and recipient organism.

Animals↗
PubMed2000

Dietary exposures to food contaminants across the United States.

Food consumption is an important route of human exposure to pesticides and industrial pollutants. Average dietary exposures to 37 pollutants were calculated for the whole United States population and for children under age 12 years by combining contaminant data with food consumption data and summing across food types. Pollutant exposures were compared to benchmark concentrations, which are based on standard toxicological references, for cancer and noncancer health effects. Average food ingestion exposures for the whole population exceeded benchmark concentrations for arsenic, chlordane, DDT, dieldrin, dioxins, and polychlorinated biphenyls, when nondetects were assumed to be equal to zero. For each of these pollutants, exposure through fish consumption accounts for a large percentage of food exposures. Exposure data for childhood age groups indicated that benchmark concentrations for the six identified pollutants are exceeded by the time age 12 years is reached. The methods used in this analysis could underestimate risks from childhood exposure, as children have a longer time to develop tumors and they may be more susceptible to carcinogens; therefore, there may be several additional contaminants of concern. In addition, several additional pollutants exceeded benchmark levels when nondetects were assumed to be equal to one half the detection limit. Uncertainties in exposure levels may be large, primarily because of numerous samples with contaminant levels below detection limits.

Adolescent↗
PubMed1981

Occurrence and methods of control of chemical contaminants in foods.

Contamination of food by chemicals can result from their use on agricultural commodities; accidents or misuse during food handling and processing; nucler weapon testing and operation of nuclear power plants; and disposal of industrial chemicals or by-products with subsequent dispersal into the environment. The Food and Drug Administration (FDA), as the Federal agency mainly responsible for evaluating the hazards of chemical contaminants and enforcing any established tolerance levels for them in foods, has been monitoring pesticides, industrial chemicals, metals, and radionuclides in foods in its nationwide programs for many years. In addition, FDA searches for potential contaminants among the approximately 50,000 industrial chemicals manufactured in the United States and coordinates its efforts with those of other Federal and state agencies in these investigations. The overall results of the FDA surveillance and compliance programs for chemical contaminants in foods, as well as specific examples illustrating the wide range of incidents and types of occurrences, are presented.

Chemical Industry↗
PubMed1997

Mite-contaminated foods as a cause of anaphylaxis.

BACKGROUND: Although insect and arthropod contamination of certain foods has been recognized for many years, allergic manifestations caused by ingestion of mite allergens have only rarely been reported. OBJECTIVE: The purpose of this study is to present clinical observations in patients who experienced acute anaphylaxis after eating mite-contaminated foods. METHODS: Thirty atopic subjects who were first seen with systemic anaphylaxis precipitated by the ingestion of wheat-containing foods underwent skin prick tests with inhalant and food extracts, as well as with uncontaminated and mite-contaminated wheat flour. Flour samples were examined microscopically for identification and counting of mites. Der p 1 and Der f 1 levels were quantitated by using immunochemical methods. RESULTS: The most common symptoms were breathlessness, angioedema, wheezing, and rhinorrhea, which started between 10 and 240 minutes after eating. Abundant mites were present in the flour obtained from 28 patients; Suidasia spp. mites were found in grated bread from the other two patients. Positive prick test responses to Dermatophagoides farinae-and mite-contaminated flour and negative skin test responses to wheat extract, other food extracts, and uncontaminated wheat flour were found in all patients. Skin test responses were positive in volunteers with mite allergy even after heating the mite-contaminated flour at 100 degrees C. Screening of 35 unselected flour samples demonstrated the presence of mites in 13 of them (37.1%). CONCLUSIONS: Systemic anaphylaxis can occur after the ingestion of heated or unheated mite-contaminated foods. This problem may be more prevalent in tropical and subtropical countries than previously recognized.

Adolescent↗
PubMed2002

Potential food contaminants and associated health risks.

The potential toxicants in food are derived from natural or industrial sources. Compounds like lectins and glycoalkaloids that are toxic to man are naturally present in some vegetables like potatoes or legumes. A wide variety of marine toxins mostly produced by dinoflagellates occurring secondarily in molluscs and mussels are usually ingested by human beings causing poisoning. On the other hand, toxic compounds find their way into food during manufacture, storage, or transportation. These include largely the industrial contaminants, persistent organic pollutants (POP), pesticides, heavy metals, and toxins of fungal and bacterial origin. Further, toxic compounds like higher alcohols may be produced as byproducts during processing. Migration of compounds from packaging materials into packaged food like contamination with lead from solder in certain metal cans is well known. Additives (emulsifiers, preservatives, and antioxidants) could also influence the quality of foods. Solvent residues may find their way into food as a result of their use in extraction processes like the use of trichloroethylene and methylene chloride in decaffeination of coffee. In addition, poor hygiene, storage, and preparation may also lead to food contamination by various microbes and ova or cysts of nematodes. The problem of food contamination can be overcome to a great extent by regular surveillance and monitoring programmes and strict implementation of food and adulteration act. In the present review some of these aspects of food contamination have been discussed in detail.

Animals↗
PubMed1986

Significance of contaminated food in collective dose after a severe reactor accident.

The importance of the ingestion dose pathways in collective effective dose due to severe reactor accidents is evaluated by studying two different radioactive accidental releases. A short description of the ingestion dose pathway model is also given. Typically, exposure via contaminated food without countermeasures causes considerably more than half of the collective effective dose in the long term, and milk consumption is the most important pathway. Also the season when the release occurs has a major effect on the doses and on the areas where food products should be interdicted.

Accidents↗