Evaluation of certain food additives and contaminants. Forty-first report of the Joint FAO/WHO Expert Committee on Food Additives.
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Animals↗
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Food poisoning syndromes.
Despite our society's advances in sanitation, food preservation, and hygiene, the prevalence of foodborne disease remains high (12.6 million cases per year in the United States). Although there is a constant need for education of food handlers and consumers, there is also a need for continued vigilant monitoring of coastal waters, meat packing facilities, and imported foods. As long as antibiotics are used in poultry and cattle feeds, one can expect the incidence of antibiotic-resistant foodborne pathogens to rise. There are several promising areas of research in the field of foodborne illnesses. Molecular biologists are actively characterizing the genes that enable invasive enteric pathogens such as Salmonella and Yersinia to enter tissues, and the bacterial toxins associated with secretory diarrheas continue to be the subject of intense scrutiny. Epidemiologists are implementing new techniques such as DNA fingerprinting and multilocus enzyme electrophoresis for tracing pathogens in disease outbreaks. Similarly, the use of computers in the food industry facilitates the tracing of contaminated foods. Although the rates of foodborne illness may not decrease significantly during the next decade, we can expect more rapid identification and tracing of outbreaks as well as an improved understanding of the pathogenesis of the foodborne diseases.
Diarrhea↗
Microbial food borne pathogens. Salmonella.
All food animals are susceptible to infection with Salmonella, a genus of gram negative, nonspore-forming, usually motile, facultative anaerobic bacilli belonging to the family Enterobacteriaceae. Salmonella are differentiated into over 2200 serologically distinct types (serotypes) based on differences in somatic, flagellar, and capsular antigens. Infection with Salmonella may or may not lead to a sometimes fatal salmonellosis, a disease that can remain localized in the gastrointestinal tract as gastro-enteritis, or become generalized as a septicemia and affect several organ systems. Infected food animals that do not develop salmonellosis, and those that recover from the disease, become carriers of Salmonella and serve as sources of infection to humans and other animals. Apart from being a source of Salmonella food poisoning for humans, Salmonella-contaminated food animal carcasses are also a concern because they are a source of antibiotic-resistant Salmonella.
Animals↗
[Transmissible spongiform encephalopathies in animals].
Transmissible spongiform encephalopathies in animals are known for centuries. In particular scrapie in sheep and goats occurs worldwide; it spreads as a natural disease and is genetically controlled. Chronic wasting disease (CWD) in the United States (Wyoming and Colorado) also spreads as natural disease among free ranging and captive elk and mule deer. In contrast, transmissible mink encephalopathy (TME) of mink in fur producing farms is caused by contaminated feed; the source of this food contamination is still controversial. The only occurrence of a TSE in an avian species was reported from a flock of ostriches in a German zoo. The origin of the outbreak of bovine spongiform encephalopathy (BSE) in Great Britain could be traced back to feeding concentrates containing animal proteins contaminated with the agent of sheep scrapie. BSE was introduced into other countries, e.g. Switzerland and France, through the import of contaminated feeds from Great Britain. In addition, sporadic cases of TSE occurred in 10 other species, in particular domestic cats and zoo animals, e.g. antelopes and large cats. The diagnosis is based on the neuropathological examination of the brain as well as the demonstration of the disease specific protease resistant prion protein (PrPres). The first measures against the disease aim at eliminating the risk factors. The most important is the prohibition of feeding animal protein concentrates to ruminants. Thanks to this measure the incidence of BSE diminished remarkably. To protect consumers of beef products, in countries with BSE the potentially infectious organs of all cattle are confiscated at slaughter. Yet, in Great Britain this measure was introduced only at a point of time when BSE had already spread all over the country. Therefore, there is a strong probability of an exposition of consumers of beef with the BSE agent, which might have caused the new variant of Creutzfeldt-Jakob disease (nvCJD).
Animal Feed↗
Worldwide occurrence of mycotoxins in foods and feeds--an update.
In a review presented at the first FAO/WHO/UNEP Conference on Mycotoxins in 1977, the occurrence of aflatoxins, zearalenone, ochratoxin A, citrinin, trichothecenes, patulin, penicillic acid, and the ergot alkaloids was indicated to be significant in naturally contaminated foods and feeds. The information presented on aflatoxin contamination greatly exceeded that for all other mycotoxins combined. This study reviews the worldwide levels and occurrence of mycotoxins in various commodities since 1976. Comparatively few countries have lowered the acceptable levels for aflatoxins in susceptible commodities. However, intensified efforts are needed to establish control of aflatoxin levels in the global food supply, particularly in peanuts, tree nuts, corn, and animal feeds. Extensive deoxynivalenol (DON) contamination of grains, especially wheat, was demonstrated. Co-contamination of grains by Fusarium toxins, especially DON and nivalenol, with zearalenone to a lesser extent, was reported. However, more information on co-occurrence of Fusarium toxins in cereals should be developed. When contamination of feeds by ochratoxin A was significant, this toxin occurred in swine kidney and smoked meats in high levels. On the basis of occurrence and/or toxicity, patulin and penicillic acid contamination of foods does not appear to be of real concern. More recent developments suggest, however, that expanded monitoring studies of Alternaria toxins, moniliformin, citrinin, cyclopiazonic acid, penitrem A, and ergot alkaloids are indicated.
Animal Feed↗
Immunotoxic activity of ochratoxin A.
Ochratoxin A (OTA) is an immunosuppressant fungal compound, produced by toxigenic species of Aspergillus and Penicillium fungi in a wide variety of climates and geographical regions. The contamination of food by this mycotoxin takes place primarily during preharvest periods. Almost all types of food can be contaminated. In addition, its chemical stability against heat and during industrial food processing makes OTA one of the most abundant food contaminating mycotoxins. Due in part to its long serum half-life in man, almost 100% of all human blood samples from some geographic regions may be positive for OTA. The immunosuppressant activity of OTA is characterized by size reduction of vital immune organs, such as thymus, spleen, and lymph nodes, depression of antibody responses, alterations in the number and functions of immune cells, and modulation of cytokine production. The immunotoxic activity of OTA probably results from degenerative changes and cell death following necrosis and apoptosis, in combination with slow replacement of affected immune cells, due to inhibition of protein synthesis.
Animals↗
Carcinogens in food: priorities for regulatory action.
A pragmatic possible approach to the prioritization of chemical carcinogens occurring as food contaminants is described, based on the carcinogenic risk to the population. This should be of value in ensuring that resources for assessment and management of carcinogens in food are directed to the most important areas with regard to carcinogenic risk to the population. Key components of this approach are an assessment of the carcinogenic hazard to humans combined with estimations of intakes per person and of the proportion of the population exposed. These are used to derive an index referred to as the Population Carcinogenic Index. Concerning the hazard assessment expert judgement is used to place the chemical in one of five categories. The highest category is for chemical carcinogens that are believed to act by a genotoxic mechanism. It is recognised that such compounds may vary enormously with respect to their potency and various approaches to ranking carcinogens on the basis of potency are reviewed. The approach adopted is to subdivide the genotoxic carcinogens category into high, medium and low potency based on the TD50 value. Methods of estimating intakes and exposed populations are considered and an approach which groups these into broad categories is developed. The hazard and exposure assessments are then combined to derive the Population Carcinogenicity Index.
Carcinogens↗
[Intestinal parasitosis in canteen employees: a quadrennial study].
Giardia Lamblia is the flagellated protozoan of intestinal-tract more frequently diagnosed. This disease is well known all over the world, particularly in hot countries and under precarious hygienic-environmental conditions. In Italy the rate of infestation is around 8%. The giardiasis affects people of every age. The disease can be transmitted either by direct contagion or through the ingestion of food contaminated by cysts. Some A.A. believe that in the last years real epidemics in adults occurred, due to the current changing in the habits of life, in particular as regards food and the use of canteens. The italian law demands the competent sanitary authorities to prepare diagnostical procedures for sanitary checks, to be carried out for consignment and renewal of the employment card and for periodical checks on production, manipulation, transport and sale-staff. In a quadrenniale study (1985-1988) the A.A. estimate the incidence of the intestinal parasites and they evaluate the real danger and risks deriving from the contamination of food, by checking 160 canteen-men working in a know metal-mechanical industry in our country, through periodical parasitological stool examination. The parasitological stool exam was carried out bright and after enrichment by Ritchie's method. The Giardia Lamblia, that certainly is the ++intestinal parasite more often isolated in our country, has been observed with varying frequency during the examined period from 1.9% to 5.6%. In 4 years, 38% of these patients, even undergoing specific therapy, has shown relapsing and recurrent infestations both in the following year and later.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
90Sr, 238U, 234U, 137Cs, 40K and 239/240Pu in Emmental type cheese produced in different regions of Western Europe.
A method is presented for the determination of (90)Sr and uranium in Emmental type cheese collected in dairy plants from different European countries. Results display a significant correlation (r = 0.708 Student t-test = 6.02) between the (90)Sr content of the cheese and the altitude of grazing. The highest (90)Sr activity is 1.13 Bq kg(-1) of cheese and the lowest is 0.29 Bq kg(-1). Uranium activity is very low with a highest (238)U value of 27 mBq kg(-1). In addition, (234)U/(238)U ratio shows a large enrichment in (234)U for every location. Without any significant indication of the geographic origin of the cheese, this enrichment is believed to be due to the geological features of the pasture, soil and underground water. These results tend to prove that the contamination of milk by uranium originates principally from the water that the cows drink instead of the forage. This finding may have a great importance in models dealing with dairy food contamination by radionuclides following a nuclear accident. Also, the (90)Sr content and to a lesser extent the (234)U/(238)U ratio could be used to trace the authenticity of the origin of the cheese. (137)Cs activity is lower than the detection limit of 0.1 Bq kg(-1) in all the samples collected (n = 20). Based on natural (40)K activity in cheese (15-21 Bq kg(-1)), the decontamination factor for the alkaline cations from milk to cheese is about 20. Plutonium activity stays below the detection limit of 0.3 mBq kg(-1).
Animals↗
Rapid surface plasmon resonance-based inhibition assay of deoxynivalenol.
Deoxynivalenol belongs to a group of highly toxic fungal metabolites produced by Fusarium species that may contaminate food and animal feed, mostly grains. Three different monoclonal mouse anti-deoxynivalenol antibodies were compared for the development of a surface plasmon resonance (SPR)-based immunoassay for the selective and quantitative determination of deoxynivalenol in naturally contaminated matrices. A conjugate of deoxynivalenol with the protein casein was prepared and immobilized on the sensor chip surface. An excess of antibody was added to each test solution before the measurement. The assay was based on the competition for antibody binding between the immobilized deoxynivalenol conjugate on the sensor and the free deoxynivalenol molecules in the test solution. The deoxynivalenol-casein sensor could be reused more than 500 times without significant loss of activity using 6 M guanidine chloride solution for regeneration. The cross-reactivity of the three antibodies in the SPR assay was tested with other trichothecene mycotoxins (3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, nivalenol, HT2-toxin, and T2-toxin). The only sample preparation was extraction with max 80 vol % acetonitrile and 10-fold dilution with the running buffer. The assay had an optimal range between 2.5 and 30 ng/mL deoxynivalenol in the test solution. Most results of the SPR-based assay were in agreement with liquid chromatography/tandem mass spectrometry measurements of naturally contaminated wheat samples.
Antibodies, Monoclonal↗
Field desorption mass spectrometry of cyanogenic glycosides.
The field desorption mass spectra of several underivatized cyanogenic glycosides exhibit molecular ions or ions derived from the parent compound by protonation and alkali metal cationization. Abundant fragment ions are present and can be readily related to structure. Significant deviations from established fragmentation pathways are observed due to the nature of the aglycone. The ability to successfully determine the presence of cyanogenic glycosides by field desorption is demonstrated in crude extracts isolated from Vicia sativa, a food-contaminating plant material.
Crystallization↗
[Concentrations of persistent toxic compounds in the Spanish population: a puzzle without pieces and the protection of public health].
The contamination by persistent toxic compounds (PTCs) of the general population is a fact of relevance from a public health perspective. It is also relevant to health care professionals, as well as for environmental, food, industrial and economic policies. Though in Spain information on food contamination by PTCs shows large time and geographic gaps, the scarcity of data is even more severe on the concentrations that PTCs have in people: a representative study of a general healthy population living in a wide geographic area has never been conducted in the country. However, the available studies indicate that around 80-100% of the population has detectable concentrations of DDE, PCBs, hexachlorbenzene or lindane. Studies on the effects that PTCs have upon humans are extremely infrequent in Spain. Yet, the international literature suggests that some PTCs may induce significant biological and clinical effects at doses below those traditionally deemed "safe". The mechanism of action of PTCs are not restricted to endocrine disruption. Assessing the clinical and social relevance of the more subtle and long-term effects of PTCs presents interesting challenges and opportunities. Spain and other European countries lack population indicators on the impact that environmental processes have on human health. Several government levels have a role to fulfill in the monitoring of biological levels of PTCs among persons in order to assess the risks of adverse health effects. Along with over a hundred other countries. Spain will soon try to implement the Stockholm treaty on persistent organic pollutants (POPs). This constitutes a new opportunity to develop more efficient policies to control PTC residues in food, humans and the environment. As part of the treaty implementation it is necessary to launch a Report on factors that influence body concentrations of PTCs in the Spain general population.
Animals↗
Chronic effects of Cu on reproduction of Polypedilum nubifer (Chironomidae) through water and food.
The effects of Cu on the reproduction of Polypedilum nubifer (Chironomid) through water and food were examined in a flowthrough aquarium by Cu exposure from the egg stage. The emergence success decreased to 74, 38, 16, and 2% of the control at 10, 20, 30, and 40 micrograms Cu/liter, respectively. However, the oviposition success (No. of egg clusters/female) remained at 64% of the control value even at 30 micrograms Cu/liter. From these results and the acute toxicity test, it was suggested that a decrease in emergence success was caused mainly by mortality in the early instar stage, when Cu sensitivity is high. There were no significant effects of Cu on the emergence success, oviposition success, and hatchability of the oviposited eggs in the midge which had been given food contaminated with about 330 micrograms Cu/g (dry weight). However, emergence success and hatchability of the oviposited eggs decreased to 30 and 40% of the control in the midge which had been fed food accumulating 1770 micrograms Cu/g, although the oviposition success was not impaired compared to the control. Emergence did not occur from the aquaria fed food accumulating 5200 micrograms Cu/g.
Animals↗
Twelve-hour PCR-based method for detection of Salmonella spp. in food.
A PCR-based method for the detection of Salmonella spp. in food was developed. The method, set up on typical salami from the Italian region of Marche, is sensitive and specific and shows excellent correlation with the conventional method of reference when naturally contaminated foods are analyzed. Moreover, it can be easily performed within a maximum of 12 h from food sampling, thus allowing prompt detection of Salmonella spp. in the food stocks analyzed.
Animals↗
[INFECTIONS IN THE HOSPITAL].
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Bacillus↗
Evaluation of a 5'-nuclease (TaqMan) assay for the detection of virulent strains of Yersinia enterocolitica in raw meat and tofu samples.
Culture methods for detecting virulent Yersinia enterocolitica require selective enrichment and a series of confirmatory tests that are time-consuming, costly, and laborious. The objective of this study was to evaluate a fluorogenic 5'-nuclease assay for detecting the enterotoxin yst gene of virulent Y. enterocolitica in pure cultures, inoculated ground pork samples, and naturally contaminated food samples. These results were then compared with "gold standard" methods recommended by the U.S. Food and Drug Administration in the Bacteriological Analytical Manual for detecting pathogenic Y. enterocolitica. The 5'-nuclease assay was able to identify the organism in 100% of the repetitions when 10(2) CFU/ml or more organisms were present in pure cultures and 10(3) CFU/g or more organisms were present in ground pork. Similar recovery efficiency on cefsulodin-irgasan-novobiocin (CIN) agar plates was only evident when 10(5) CFU/ml or more organisms were present in pure culture and 10(6) CFU/g or more organisms were present in inoculated ground pork. The 5'-nuclease assay indicated a contamination rate of 35.5% (94/265) in various meats and tofu, whereas the CIN plating method indicated a contamination rate of 28.3% (75/265). This resulted in 100% sensitivity and 64.5% specificity for the 5'-nuclease assay when compared with the standard culture recovery method. Only 75% (60/80) of the Yersinia spp. isolated on CIN was identified as containing a virulence plasmid by autoagglutination and crystal violet binding tests. These results indicate that the true rate of contamination of virulent Y. enterocolitica in pork and other processed meats and foods is being underestimated using current detection methods. This study demonstrates the potential of the 5'-nuclease assay for rapidly and specifically detecting virulent Y. enterocolitica in processed foods with the added advantage of being an automated detection system with high-throughput capability.
Animals↗
[Aflatoxins in newly harvested corn in Panama].
Mycotoxins are fungal metabolites that may contaminate foods and feeds, resulting at times in important disease in humans and animals. Thirty-six samples of nine varieties of newly harvested corn (4 samples each variety) were analyzed in search of aflatoxins by thin layer chromatography and high pressure liquid chromatography, and also cultured for the presence of Aspergillus flavus. Of the 36 samples studied, one was contaminated with 1290 ppb aflatoxin B1, which is 258x the concentration suggested by WHO, placed at 5 ppb in food for human consumption. Culture of the 36 samples of corn resulted in growth of 55 colonies of A. flavus from all but two (1 and 6) of the 9 varieties. Of the 55 colonies of A. flavus obtained, 15 (27.3%) were toxigenic. Comments are made on the public health implications of these findings.
Aflatoxins↗
The fate of environmental contaminants in the food chain.
This paper reviews the major sources of industrial environmental pollutants that may give rise to organic contaminants in foods, indicates which foods tend to be most frequently found to be contaminated and summarises available data on levels of occurrence. Polycyclic aromatic hydrocarbons (PAHs), phthalic acid esters, polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs), polychlorinated biphenyls (PCBs) and organic phosphates are widespread environmental contaminants which have all been detected in foods. Estimates of exposure to these contaminants from total diet and other studies are summarised. Some pollutants such as volatile halocarbons and benzene tend to only occur as localised contaminants for which targeted monitoring of foods is necessary. The most difficult area is regarded as the detection of previously unrecognised contaminants in foods for which some possible approaches are described.
Environmental Pollutants↗