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At least 1,189 records · Page 66Linked to original sources
PubMed2003

Development of a triplex PCR assay for the specific detection of Campylobacter jejuni, Salmonella spp., and Escherichia coli O157:H7.

A triplex PCR assay was developed and evaluated for efficacy in detecting Campylobacter jejuni, Salmonella spp., and Escherichia coli O157:H7 in a variety of raw and ready-to-eat food products. Following a short enrichment period, artificially contaminated food samples were subjected to a triplex PCR assay, which incorporated published primers for each food pathogen, a protocol for sample collection, and a PCR procedure designed specifically for the assay. The selected primers amplified fragment sizes of 159 bp, 252 bp, and 360 bp for C. jejuni, E. coli O157:H7, and Salmonella spp., respectively. This assay provides specific and reliable results and allows for the cost-effective detection of all three bacterial pathogens in one reaction tube.

Bacteriological Techniques↗
PubMed2004

Polybrominated diphenyl ethers contamination of United States food.

Elevated levels of polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant, were recently detected in U.S. nursing mothers' milk. These halogenated compounds chemically and toxicologically resemble others such as polychlorinated biphenyls (PCBs), whose route of intake is almost exclusively through food of animal origin. This study is the first to report the levels of PBDEs in U.S. foods in a market basket survey of 30 food types (total of 32 food samples) from three major supermarket chains in Dallas, TX. Food samples were almost exclusively foods of animal origin: meat, fish, and dairy products. Thirteen PBDE congeners were measured for each sample. Levels were then compared to existing PBDE food studies from other countries where available. In this study, levels of PBDEs are highest in fish, then meat, and lowest in dairy products; median levels were 1725 (range 8.5-3078), 283 (range 0.9-679), and 31.5 (0.2-1373), parts per trillion (ppt), or pg/g, wet weight, respectively. Nonfat milk did not have any detectable PBDE levels. In fish, PBDE congener 47 (2,2',4,4'-tetraBDE) contributes up to 70% of the total PBDEs, followed by congeners 100 (2,2',4,4',6) and 99 (2,2',4,4',5). In meat congener 99 predominates, followed by 47. In dairy, BDE 47 predominates followed by 99. U.S. food PBDE levels measured in this study are higher than reported in two other published market based studies from Spain and Japan. Although these findings are preliminary and will be updated with analyses of new samples, they suggest that food is a major route of intake for PBDEs.

Dairy Products↗
PubMed2001

Tracing of Salmonella spp. in two pork slaughter and cutting plants using serotyping and macrorestriction genotyping.

AIMS: The origin of Salmonella contamination of pork products is not well established. In order to further this knowledge, the transmission of Salmonella spp. from live pigs to pork cuts was investigated in two pork slaughter and cutting plants. METHODS AND RESULTS: Salmonella spp. were isolated from both pork (pigs, carcasses, cuts) and the environment before and during slaughterhouse activities. Eight serotypes were identified. XbaI and SpeI macrorestriction distinguished 20 genotypes of Salmonella Typhimurium and 16 genotypes of Salmonella Derby. A major cluster of Salmonella Typhimurium genotypes was common to both plants and all pig-related genotypes, while a predominant pig-related Salmonella Derby genotype was common to both plants. CONCLUSION: None of the Salmonella strains persisted for long periods in the pork-processing environments. SIGNIFICANCE AND IMPACT OF THE STUDY: This work shows that contaminated live pigs, because of bacterial spread due to the process and ineffective cleaning procedures, are involved in Salmonella contamination.

Abattoirs↗
PubMed2006

Ecophysiology of ochratoxigenic Aspergillus ochraceus and Penicillium verrucosum isolates. Predictive models for fungal spoilage prevention - a review.

Ochratoxin A (OTA) is a secondary metabolite produced by several species of Aspergillus and Penicillium; among them Aspergillus ochraceus and Penicillium verrucosum are two ochratoxigenic species capable of growing in different climates and thus contamination of food crops with OTA can occur worldwide. OTA can be found in a wide range of foods such as cereals, coffee, cocoa, spices, beer, wine, dried vine fruit, grapes and meat products. OTA is toxic to animals, it presents neurotoxic, immunotoxic and nephrotoxic effects. It has been implicated in a human kidney disorder known as Balkan Endemic Nephropathy. This review focuses on the ecophysiology of ochratoxin-producing Aspergillus ochraceus and Penicillium verrucosum, the effect of environmental factors on their germination, mycelial growth, and OTA production. Knowledge of environmental conditions required for sucessive stages of fungal development represent the first step towards preventing mycotoxin formation. Predictive models for different stages of fungal development are presented, which allow prediction of the time before spoilage as a function of the abiotic factors. Finally, the implications of these studies in management of barley, coffee and grapes are described. This can help to identify the critical control points in their production, storage and distribution processes.

Aspergillus ochraceus↗
PubMed2005

Molecular characterization of Listeria monocytogenes of the serotype 4b complex (4b, 4d, 4e) from two turkey processing plants.

Most foodborne outbreaks of listeriosis have been found to involve a small number of closely related strains of Listeria monocytogenes serotype 4b. The ecology of these organisms and their reservoirs in nature or in the processing plant environment, however, remain poorly understood. Surveys of environmental samples from two turkey processing plants in the United States indicated presence of L. monocytogenes of the serotype 4b complex (serotype 4b and the closely related serotypes 4d and 4e). In addition, environmental and raw product samples from one plant repeatedly yielded isolates with genetic markers typical of two major serotype 4b epidemic clonal groups, ECI and ECII. The pulsed field gel electrophoresis (PFGE) profiles of these isolates, however, were clearly distinct from those of confirmed epidemic-associated strains. Furthermore, we observed minor but consistent differences in PFGE profiles of isolates that harbored ECI- or ECII-specific genetic markers, and that were obtained at different sampling times from the same plant. The findings suggest processing plant persistence (or repeated introductions) and genomic diversification of L. monocytogenes serotype 4b isolates that harbor ECI- or ECII-specific genetic markers. Such diversification would need to be taken into consideration in further efforts to elucidate the evolution and epidemiology of these organisms.

Animals↗
PubMed1985

Transport of elements from soil to human diet: an alternative approach to pathway analysis.

Transport from soil to human dietary intake is conventionally treated by analyzing the various pathways through uptake by plant roots and transfer from animal feed into milk and meat. An alternative approach is proposed requiring only the average daily human ingestion of each element and its abundance in soil, both readily available for most elements. The two methods are compared quantitatively and give results consistent within a mean factor of four, which is roughly the standard deviation in estimates from the pathway analysis. Neither method gives consistently larger or smaller transfer rates. Each method has important advantages in some applications.

Animal Feed↗
PubMed1982

Food science and nutrition: the gulf between rich and poor.

The people of economically developed countries benefit greatly from modern food science. They are protected from food contamination, have access to a great variety of food, and need spend little time preparing it. The poor in developing countries enjoy few of the benefits of food science. Their diets are often nutritionally deficient and they spend many hours each day processing their food and searching for wood with which to cook it. In most tropical countries food losses between harvest of slaughter and eventual consumption are inestimable. Efforts to improve post-harvest food systems in developing countries require the attention and ingenuity of many scientific disciplines and the support of all development agencies.

Cooking↗
PubMed1963

Incidence of Clostridium perfringens in American foods.

Food samples were examined for the presence of Clostridium perfringens. A medium described by Mossel and later modified by Angelotti et al. was used for the detection and enumeration of C. perfringens. The incidence of C. perfringens observed in the foods examined was 6.1%. C. perfringens was recovered from 2.7% of the commercially prepared frozen foods, 3.8% of fruits and vegetables, 5.0% of spices, 1.8% of home-prepared foods, and 16.4% of raw meat, poultry, and fish.

Animals↗
PubMed1963

Psychrophilic and mesophilic fungi in frozen food products.

The mold flora of certain frozen pastries and chicken pies was investigated. Molds were determined qualitatively or quantitatively, or both, by preparing pour plates of the blended product and incubating the plates at various temperatures. The mesophilic fungal flora developed on plates incubated at 10 and 20 C, whereas psychrophilic fungi were obtained on plates incubated at 0 and 5 C. About 2,000 cultures of fungi, representing about 100 different species, were isolated from various products. Four different brands of blueberry, two brands of cherry pastries, two brands of apple, and one brand of raspberry pastries were examined. In addition, two brands of chicken pies were studied. Blueberry pastries had a much higher total fungal population than the other products, although different brands of blueberry pastries varied considerably. Blueberry pastries had from 347 to 1,586 psychrophilic fungi per g. Cherry pastries had about 70 to 110 psychrophiles per g, and apple pastries had 19 to 92 psychrophiles per g. Chicken pies contained very few psychrophilic fungi, about 15 per g. Aureobasidium pullulans was recovered most frequently. About 90% of the psychrophilic fungi found in blueberry products was A. pullulans. Depending upon the brand of cherry pastry, either Phoma spp. or A. pullulans was the most common fungus present. Apple pastries also displayed brand variation, but were unique in having many mesophilic aspergilli. This genus was generally absent from other products. The Penicillium content of apple pastries was also rather high; 50% of the psychrophilic flora was represented by this genus. The psychrophilic fungal flora of chicken pies was composed primarily of penicillia (50%) and Chrysosporium pannorum (46%).

Aspergillus↗
PubMed1964

COMPARISON OF TWO METHODS FOR THE ISOLATION OF SALMONELLAE FROM IMPORTED FOODS.

Two methods for the detection of salmonellae in foods were compared in 179 imported meat and egg samples. The number of positive samples and replications, and the number of strains and kinds of serotypes were statistically comparable by both the direct enrichment method of the Food Hygiene Laboratory in England, and the pre-enrichment method devised for processed foods in the United States. Boneless frozen beef, veal, and horsemeat imported from five countries for consumption in England were found to have salmonellae present in 48 of 116 (41%) samples. Dried egg products imported from three countries were observed to have salmonellae in 10 of 63 (16%) samples. The high incidence of salmonellae isolated from imported foods illustrated the existence of an international health hazard resulting from the continuous introduction of exogenous strains of pathogenic microorganisms on a large scale.

Animals↗
PubMed1964

BACTERIOLOGY OF SPOILAGE OF FISH MUSCLE. II. INCIDENCE OF SPOILERS DURING SPOILAGE.

A test medium consisting of a sterile raw press juice from fish muscle was used to determine the incidence of spoilage bacteria on stored fillets of English sole (Parophrys vetulus). The initial load of spoilers was shown to be consistently below 10%. This percentage rose but slightly toward the middle of the spoilage runs, and actually declined when spoilage was most apparent both organoleptically and chemically. Further evidence implicating the Pseudomonas and Achromobacter groups in the spoilage of fresh fish is presented.

Achromobacter↗
PubMed1965

IMPROVED TEMPERATURE-GRADIENT INCUBATOR AND THE MAXIMAL GROWTH TEMPERATURE AND HEAT RESISTANCE OF SALMONELLA.

An improved all-metal temperature-gradient incubator produces its gradient by means of a bar permanently installed in a near-vertical position with its lower end in a cool constant-temperature water bath and with thermostatically controlled heaters near its top. Bolts hold the incubator in contact with the temperature-gradient bar, and polyurethane foam insulates the entire assemblage during use. Maximal growth temperatures of 34 representative strains of Salmonella were found to be between 43.2 and 46.2 C. In an agar medium with an initial level of 10(6) cells per milliliter, no strain survived 50 C for 48 hr. S. senftenberg 775W showed no greater heat resistance at or near 48 C than did other species or other S. senftenberg strains. However, it was considerably more resistant than other strains at 55 C.

Bacteriological Techniques↗
PubMed1965

INFLUENCE OF TEMPERATURE ON BACTERIAL INFECTION OF THE HEN'S EGG.

Temperature of incubation had a marked effect on infection of eggs in which the air cells had been inoculated with a washed suspension of Serratia marcescens. There was no evidence of bacterial multiplication or spoilage in eggs held at 10 C for 42 days. Multiplication occurred in the shell membranes of eggs held at 30 or at 37 C when the yolk made contact with these membranes, and continued in the contents of the egg, at which time the first signs of spoilage appeared. In a few eggs, very large populations were present in the shell membranes and in the albumen. In eggs inoculated with Pseudomonas fluorescens and held at 10 C, bacterial multiplication occurred in the shell membranes in the first 7 days of incubation. These populations did not appear to change in size in the 7- to 14-day period of incubation. Renewed multiplication and concomitant spoilage of the contents was observed in many of the eggs thereafter.

Animals↗
PubMed1968

Salmonellae associated with further-processed turkey products.

"Further-processed" turkey products, prepared from chilled, eviscerated, and thawed carcasses at two commercial turkey-processing plants, were evaluated, for the presence of salmonellae. These organisms were isolated from swab samples from 12% of chilled, eviscerated turkey carcasses, 27% of finished products, and 24% of processing equipment. The same serotypes as those found throughout a plant on any one visit were recovered from 31% of rinse-samples taken from hands and gloves of processing personnel. Salmonellae were found in samples taken on 37 of 48 visits; a greater number of recoveries were made on days when freshly killed turkeys were processed (87%) than when frozen-defrosted carcasses were processed (59%). The predominant serotype isolated from meat and environment usually changed from visit to visit. Salmonella sandiego and Salmonella anatum were the most frequent among 23 serotypes recovered. Most of the isolated serotypes are commonly associated with turkeys and have been incriminated as causative agents of human salmonellosis. The implication is that further-processed turkey products, if inadequately cooked by the consumer and if improperly refrigerated between the time of manufacture and consumption, could directly transmit salmonellae. These same products might also contaminate other foods by introducing salmonellae into food-preparation areas.

Animals↗