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PubMed1961

Time-temperature effects on Salmonellae and Staphylococci in foods. III. Thermal death time studies.

Thermal death time studies were conducted at 5 F intervals from 130 to 150 F with strains of salmonellae and enterotoxigenic staphylococci. Heat-resistant Salmonella senftenberg strain 775W, Staphylococcus aureus strains 196E and Ms149, and non-heat-resistant Salmonella manhattan were studied in custard, chicken à la king, and ham salad. The F(140) values (minutes of exposure at 140 F required to effect 100% destruction) were as follows: S. senftenberg 775W in custard 78, and chicken à la king 81.5; S. manhattan in custard 19, and chicken à la king 3.1; S. aureus 196E in custard 59, and chicken à la king 47; S. aureus Ms149 in custard 53, and chicken à la king 40. The end points of survival-kill at all the test temperatures for both salmonellae and staphylococci in ham salad were considerably less than for the other foods studied.D(140) values (minutes of exposure at 140 F required to effect a 90% reduction in numbers) were also calculated from the data and presented. Values for z(F) and z(D) (slope of the thermal-death-time and decimal-reduction-time curves) are also presented and discussed in relation to type of food, organism, and temperature. These data indicate that heating perishable foods of the type studied to 150 F and holding every particle of food at this temperature for at least 12 min reduces 10 million or less salmonellae or staphylococci per gram to nondetectable levels. The same degree of destruction is achieved in similarly contaminated foods when held at 140 F for 78 to 83 min. On the basis of the calculation procedures employed, it is estimated that 45-min exposure at 140 F would be necessary to reduce 1,000 organisms per gram to nondetectable levels.

Animals↗
PubMed1994

Direct detection of Listeria monocytogenes using paramagnetic bead DNA extraction and enzymatic DNA amplification.

The potential of the polymerase chain reaction (PCR) as a tool for direct detection of Listeria monocytogenes in food and clinical samples was investigated. A specific oligonucleotide, directed against the listeriolysin 0 gene of L. monocytogenes, was coupled to paramagnetic beads and used to isolate listerial DNA from food homogenates and blood. The isolated DNA was amplified with a seminested PCR procedure, which recognized the hly gene. The detection limit for L. monocytogenes in 50 ml of a buffer solution was between 1 and 10 colony forming units (cfu). In food homogenates consisting of 10 g food and 40 ml 0.85% NaCl solution, artificially spiked with an overnight culture of L. monocytogenes, the detection limit was 1-10 cfu. The method was further evaluated by application to naturally contaminated food samples. In 250 microliters whole human blood artificially spiked with L. monocytogenes 10,000 cfu could be detected.

Base Sequence↗
PubMed1995

Isolation, and virulence profiles, of Aeromonas hydrophila implicated in an outbreak of food poisoning in Sweden.

A case of food poisoning outbreak involving Aeromonas hydrophila is reported in this study. A group of 27 people consumed a typical Swedish food "landgång" which is a type of smörgåsbord containing shrimps with mayonnaise, liver paté, ham, sausage, and legume salad which was purchased from a food store. Twenty-two of the 27 persons became ill within 20-34 hr of consumption of the food and reported the symptoms ranging from severe acute diarrhea, abdominal pain, headache, fever and vomiting. One person also fainted. The symptoms lasted for a couple of days. Of the remaining 5 healthy persons who consumed the left-over food the next day, 2 became ill with similar symptoms. The bacteriological examination of left-over food samples resulted in the isolation of A. hydrophila from shrimps with mayonnaise, smoked sausage, liver paté and boiled ham. The total number of A. hydrophila in these foods were log 10(6) to log > 10(7) organisms per gram of food sample. A. hydrophila was however, not isolated from legume/mayonnaise salad samples. All the food samples tested showed low numbers of other expected food contaminating organisms such as coliforms at 37 C and 44 C, fecal streptococci, Staphylococcus aureus, fungi and yeast etc., while Bacillus cereus, Clostridium perfringens and Salmonella spp. were not detected in the food samples. Investigations of the virulence profiles of the A. hydrophila isolates showed their capacity to produce beta-hemolysin, cytotoxins, cytotonic toxins, enterotoxins, and adhesion to and invasion of human intestinal (Henle 407) cells in culture.

Acute Disease↗
PubMed1996

Psychiatric aspects of food-related physical symptoms: a community study.

Beliefs about symptoms, food and health, mood disturbance, consulting behavior, and eating habits and attitudes were assessed by postal questionnaire in 273 adults who complained of food intolerance in a community study. In contrast to previous studies conducted in allergy clinics, most subjects who reported symptoms related to foods that were judged not to be allergic on clinical grounds did not manifest significant mood disturbance, impaired social adjustment, or excessive consultation for other nonspecific physical or psychological symptoms. Subjects attributing symptoms to food sensitivity suffered less psychological impairment than those attributing symptoms to other causes such as stress, stomach or bowel disorder, or food contamination. However, an important subgroup of patients did report marked impact of symptoms on everyday life, frequent consultation in traditional and complementary medical contexts, and appreciable mood disturbance. The reported association between perceived food intolerance and psychiatric disorder in allergy clinic patients is likely to be an artifact of referral bias.

Adult↗
PubMed1981

Food allergy: current concerns.

This commentary focuses on the author's concerns with various aspects of food allergy. Strict criteria should be applied to the definition of food allergy and its diagnostic techniques. Industrial inhalational exposures, food contaminations and cross-sensitization all are important influences which demand studious attention.

Aging↗
PubMed1978

Transport and transportation pathways of hazardous chemicals from solid waste disposal.

To evaluate the impact of hazardous chemicals in solid wastes on man and other organisms, it is necessary to have information about amounts of chemical present, extent of exposure, and chemical toxicity. This paper addresses the question of organism exposure by considering the major physical and biological transport pathways and the physicochemical and biochemical transformations that may occur in sediments, soils, and water. Disposal of solid wastes in both terrestrial and oceanic environments is considered. Atmospheric transport is considered for emissions from incineration of solid wastes and for wind resuspension of particulates from surface waste deposits. Solid wastes deposited in terrestrial environments are subject to leaching by surface and ground waters. Leachates may then be transported to other surface waters and drinking water aquifers through hydrologic transport. Leachates also interact with natural organic matter, clays, and microorganisms in soils and sediments. These interactions may render chemical constituents in leachates more or less mobile, possibly change chemical and physical forms, and alter their biological activity. Oceanic waste disposal practices result in migration through diffusion and ocean currents. Surface area-to-volume ratios play a major role in the initial distributions of chemicals in the aquatic environment. Sediments serve as major sources and sinks of chemical contaminants. Food chain transport in both aquatic and terrestrial environments results in the movement of hazardous chemicals from lower to higher positions in the food web. Bioconcentration is observed in both terrestrial and aquatic food chains with certain elements and synthetic organics. Bioconcentration factors tend to be higher for synthetic organics, and higher in aquatic than in terrestrial systems. Biodilution is not atypical in terrestrial environments. Synergistic and antagonistic actions are common occurrences among chemical contaminants and can be particularly important toxicity considerations in aquatic environments receiving runoff from several terrestrial sources.

Animals↗
PubMed2006

T-2 toxin impairs murine immune response to respiratory reovirus and exacerbates viral bronchiolitis.

Exposure to immunosuppressive environmental contaminants is a possible contributing factor to increased occurrence of viral respiratory diseases. The objective of this study was to test the hypothesis that the trichothecene mycotoxin T-2 toxin (T-2), a frequent food contaminant, alters host resistance to lung infection by reovirus, a model respiratory virus. Balb/c mice (4 week old) were treated intraperitoneally with T-2 toxin (1.75 mg/kg bw) or saline vehicle and then intranasally instilled 2 h later with 10(7) plaque forming unit (PFU) of reovirus, strain Lang (T1/L) or saline vehicle. At 10 days post-instillation (PI), both virus plaque-forming responses and reovirus L2 gene expression were 10-fold higher in lungs of T-2-treated mice compared to controls. No-effect and lowest-effect levels for T-2-induced suppression of reovirus clearance were 20 and 200 microg/kg bw, respectively. Respiratory reovirus infection resulted in a mild bronchiolitis with minimal alveolitis, which was markedly exacerbated by T-2 pretreatment. Reovirus exposure induced marked increases in total cells, neutrophils and lymphocytes at 3 and 7 days PI in bronchial alveolar lavage fluid (BALF) whereas macrophages were increased only at 7 days PI. Although prior T-2 exposure attenuated total cell and macrophage counts in BALF of control and infected mice at 3 days PI, the toxin potentiated total cell, macrophage, neutrophil and lymphocyte counts in infected mice at 7 days PI. At 3 days PI, T-2 suppressed reovirus-induced IFN-gamma elevation in BALF, but enhanced production of IL-6 and MCP-1. T-2 pretreatment also suppressed reovirus-specific mucosal IgA responses in lung and enteric tract, but potentiated serum IgA and IgG responses. Taken together, T-2 increased lung viral burden, bronchopneumonia and pulmonary cellular infiltration in reovirus-infected mice. These effects might be attributable to reduced alveolar macrophage levels as well as modulated cytokine and mucosal Ig responses.

Animals↗
PubMed2002

Occurrence of enterotoxigenic Staphylococcus aureus in food.

Gastroenteritis is one of the most frequent microbial diseases, which is caused by the ingestion of food contaminated with staphylococcal enterotoxins. In our study, the production of staphylococcal enterotoxins A, B (SEA, SEB) and the presence of respective staphylococcal enterotoxin genes were investigated in the field S. aureus isolates obtained from foods and food industry manufactures in East Slovakia. Radioimmunoassay (RIA), polymerase chain reaction (PCR) and dot-blot hybridisation were used for examination. The ability to synthesise enterotoxins was found in 20 (39.2%) of the total number of 51 isolates. Production of SEA was recorded in 3 (5.9%), production of SEB in 12 (23.5%) and production SEA together with SEB in 5 (9.8%) staphylococcal isolates. Nine (47.4%) sheep cheese isolates of the total number of 19 produced enterotoxins, especially SEB (36.8%). S. aureus isolates from pasta were enterotoxigenic in 6 cases (33.3%). The synthesis of enterotoxins was not detected in Bryndza cheese and sausages isolates. One enterotoxigenic isolate was obtained from smears of technological equipment and 4 isolates from throat and nasal swabs. No differences in results were recorded between RIA and PCR as well as PCR and dot-blot hybridisation. Our results suggest that it is of special importance to follow the presence of enterotoxigenic S. aureus strains in foodstuffs, especially for protecting the consumers from food poisoning.

Animals↗
PubMed2006

Survival of Helicobacter pylori in artificially contaminated ultrahigh temperature and pasteurized milk.

Helicobacter pylori (H. pylori) is a very important bacterial pathogen of humans which may cause gastrointestinal illnesses ranging from gastric and duodenal ulcers to neoplastic diseases such as MALToma and gastric cancer. Transmission via contaminated food is still uncertain but several authors believe this can realistically occur and milk may act as a vehicle of infection. This paper reports the results of H. pylori survival trials in pasteurized and ultrahigh temperature (UHT) milks artificially contaminated and aerobically stored at 4 degrees C. The results obtained showed that the four strains used in this study (H. pylori nat 18-19-20 and H. pylori ATCC 43504), had a progressive reduction in bacterial load with a median survival of 9 days in pasteurized milk and 12 days in UHT milk, with approximate average of initial inoculum of 10(5) and 10(6)cfu/ml, respectively. These findings are very important to clarify the route of transmission of H. pylori to humans via food and for implementation of a correct risk analysis for food safety purposes.

Animals↗
PubMed1999

Public health aspects of antibiotic resistance monitoring in the USA.

Treatment of food-producing animals with antimicrobial agents that are important in human therapy may present a public health risk by the transfer of resistant zoonotic pathogens or resistant genes from animals to humans via consumption of contaminated food. Resistant bacteria can diminish the effectiveness of antibiotics and demand the use of more expensive or less safe alternatives. In 1996, the U. S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and the Department of Agriculture (USDA) established the National Antimicrobial Resistance Monitoring Program to prospectively monitor changes in antimicrobial susceptibilities of zoonotic enteric pathogens from human and animal clinical specimens, from healthy farm animals, and from carcasses of food-producing animals at slaughter plants. Data resulting from the monitoring program will be used to redirect antimicrobial drug use, primarily through educational initiatives directed at health practitioners, in order to diminish the development and spread of resistance. Veterinary testing is conducted at USDA's Agricultural Research Service and CDC's Foodborne Disease Laboratory is testing human isolates under contract to FDA. Both the CDC and USDA laboratories are using a semi-automated system (Sensititre, Accumed, Westlake, Ohio) for testing susceptibilities of the isolates to 17 antimicrobial agents on a minimum inhibitory concentration plate. Comparable methods for isolate handling are used in both laboratories. This paper describes the development, implementation, and objectives of the National Antimicrobial Resistance Monitoring Program, presents initial data generated by the program, and discusses future plans.

Animals↗
PubMed2005

Alterations of metabolic enzymes in Australian bass, Macquaria novemaculeata, after exposure to petroleum hydrocarbons.

Australian bass Macquaria novemaculeata were exposed to the water-accommodated fraction of Bass Strait crude oil, dispersed crude oil, or burnt crude oil to assess sublethal effects of oil spill remediation techniques on fish. Fish were exposed to these treatments for 16 days either through the water column or by way of a pre-exposed diet of amphipod Allorchestes compressa. Fish gills, liver, and white muscle were sampled and cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH) activities quantified. In all treatments containing fish exposed by way of the water column, aerobic activity increased in the gills, whereas a decrease of this enzymic activity was observed in the liver and white muscle. Exposures by way of the food pathway indicated similar trends. Anaerobic (LDH) activity increased in the gills, liver, and white muscle after waterborne exposures. Stimulation in anaerobic activity also occurred in the liver and white muscle of fish after exposure to contaminated food. CCO activity in the gills was the most sensitive biomarker when monitoring waterborne exposures to petroleum hydrocarbons. In the gills, the dispersed oil treatment resulted in the most pronounced biological response, suggesting that in the short term the use of dispersants on an oil slick might cause the most perturbations to fish metabolism.

Animals↗
PubMed2004

Use of reverse transcription and PCR to discriminate between infectious and non-infectious hepatitis A virus.

Hepatitis A virus (HAV) is a major cause of infectious hepatitis worldwide. Detection of HAV in contaminated food or water is a priority research area in laboratories worldwide. Our laboratory has reported previously the development of reverse transcription-polymerase chain reaction (RT-PCR) based detection and typing methods for HAV in contaminated shellfish and produce. It is commonly held that RT-PCR can detect viral genome, but cannot distinguish between infectious and inactivated virus. Therefore, signals obtained after PCR should be considered as false positives unless it can be shown that the sample contains virus capable of infecting a suitable host cell line in culture. We present data to show that this general assumption is not valid. Evidence is provided that demonstrate that signals generated after RT-PCR amplification of viral genome correlated well with the presence of infectious virus in the sample. Viral samples inactivated by heat or UV treatment produced significantly lower signal strength that paralleled infectivity of the sample in cultured cells. The loss of signal strength is most likely the result of damage to the viral RNA that renders it unsuitable for RT-PCR. The correlation between PCR signal and infectivity was better following UV inactivation than heat treatment. The procedure may be adapted to other viruses and inactivating agents.

Base Sequence↗
PubMed2002

Food and cancer.

Food is an important factor in determining cancer incidence in many countries and regions. Food components relevant to cancer development can be divided into macro- and microcomponents. The former tends to act indirectly. The latter usually has a clearly defined action, for example as genotoxic agents. Food can have both positive (carcinogenic) and negative (preventive) effects. Total calory intake appears to have a strong positive influence on cancer incidence. Food typical of advanced nations including fat-rich food is associated with increases in breast, colon and prostate cancers. Vegetables rich in antioxidants and fibers tend to reduce cancer incidence. Carcinogenic plant alkaloids, myctoxins and other food contaminants frequently enter our bodies. Heat-cooking generates genotoxicants, including aromatic hydrocarbons (via combustion) and heterocyclic amines (HCAs) through reactions involving creatin(in)e, sugar and amino acids in meat. HCAs are relatively newcomers as food genotoxicants and can produce breast, colon and prostate cancers in rodents. Some epidemiological investigations positively correlate HCA intake and cancer incidence. HCAs can produce other toxicological effects including salivary gland atrophy and myocardial degeneration. Improved food, better life styles and developments in the functional food industry are all crucila to cancer prevention.

Animals↗
PubMed1997

Therapeutic antibiotics in animal feeds and antibiotic resistance.

Recent statutory changes involving animal drugs are expected to facilitate the therapeutic use of antibiotics in animal feeds in the United States of America. The use of antibiotics in animal feeds is controversial due to the potential development of resistant bacterial pathogens in food-producing animals which are exposed to the antibiotics and the resultant public health risk. Zoonotic micro-organisms can be transmitted to humans through contact with animal populations, either directly or through the consumption of contaminated food. Recommendations to address the public health concerns include the strengthening of professional education in the areas of infectious diseases and the appropriate selection and use of antimicrobial agents, the development of a comprehensive food safety education programme for food-animal veterinarians and animal producers, and the development of surveillance programmes to monitor antimicrobial resistance among zoonotic pathogens. Early identification of emerging resistance can facilitate a timely and appropriate public health response.

Animal Feed↗
PubMedDate not supplied

[Healthy nutrition in childhood and adolescence].

Nutrient requirements for youngsters are less known exactly than is commonly assumed. Anyway, it is possible to estimate the food consumption by healthy children on the basis of inquiries, so that present trends and problems can be assessed. Lower energy requirements call for a high relative density of nutrients in the food. The intake of these valuable, fibre-rich basic foods from whole grain however, is insufficient, whereas too much saccharose is consumed via beverages and processed milk products. Lower intake of milk leads to lower intake of calcium (the importance of calcium for reducing the incidence of fractures in advanced age is, like many other factors, still controversial). German children do not drink enough, as shown by high urine osmolalities. From all these trends, an optimised mixed food regimen can be recommended. This is described in detail. Nevertheless, intake of zinc, iodine and folic acid remains difficult. More than half of German children have enlarged thyroid glands, as sonography shows. Not so much contaminated food, but our excessive food habits due to abundance are the cause of food-induced diseases. Better toxicological methods and perspectives for a "healthy" environment and, thereby, food, are mandatory.

Adolescent↗
PubMed2001

Molecular screening of Enterococcus virulence determinants and potential for genetic exchange between food and medical isolates.

Enterococci are used as starter and probiotic cultures in foods, and they occur as natural food contaminants. The genus Enterococcus is of increased significance as a cause of nosocomial infections, and this trend is exacerbated by the development of antibiotic resistance. In this study, we investigated the incidence of known virulence determinants in starter, food, and medical strains of Enterococcus faecalis, E. faecium, and E. durans. PCR and gene probe strategies were used to screen enterococcal isolates from both food and medical sources. Different and distinct patterns of incidence of virulence determinants were found for the E. faecalis and E. faecium strains. Medical E. faecalis strains had more virulence determinants than did food strains, which, in turn, had more than did starter strains. All of the E. faecalis strains tested possessed multiple determinants (between 6 and 11). E. faecium strains were generally free of virulence determinants, with notable exceptions. Significantly, esp and gelE determinants were identified in E. faecium medical strains. These virulence determinants have not previously been identified in E. faecium strains and may result from regional differences or the evolution of pathogenic E. faecium. Phenotypic testing revealed the existence of apparently silent gelE and cyl genes. In E. faecalis, the trend in these silent genes mirrors that of the expressed determinants. The potential for starter strains to acquire virulence determinants by natural conjugation mechanisms was investigated. Transconjugation in which starter strains acquired additional virulence determinants from medical strains was demonstrated. In addition, multiple pheromone-encoding genes were identified in both food and starter strains, indicating their potential to acquire other sex pheromone plasmids. These results suggest that the use of Enterococcus spp. in foods requires careful safety evaluation.

Animals↗