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At least 163 records · Page 9Linked to original sources
PubMed1999

Effect of diacetyl on controlling Escherichia coli O157:H7 and Salmonella Typhimurium in the presence of starter culture in a laboratory medium and during meat fermentation.

Diacetyl is a flavor compound that possesses antimicrobial activity and is found in several dairy products. The effect of diacetyl on controlling the growth of two foodborne pathogens, Escherichia coli O157:H7 and Salmonella Typhimurium, when grown with Pediococcus acidilactici as a meat starter culture was evaluated in a laboratory medium and during salami fermentation. Diacetyl (50 ppm) added to each mixed culture system strongly inhibited the growth of E. coli O157:H7 and Salmonella Typhimurium in the laboratory medium (brain heart infusion, 2.3% of NaCl, 0.75% of dextrose) (P < 0.05). During meat fermentation, the growth of E. coli O157:H7 and Salmonella Typhimurium was inhibited significantly by addition of diacetyl (300 ppm) (P < 0.05) after 24 h fermentation. However, the acid production and growth of P. acidilactici were not affected by the addition of diacetyl (P > 0.05). After 24 h meat fermentation, about a 1.0-log CFU/g difference occurred in numbers of each foodborne pathogen mixed with P. acidilactici (P < 0.05) with and without 300 ppm diacetyl. Diacetyl and the acid produced by the meat starter culture reduced the growth of the two foodborne pathogens during salami fermentation. These results suggest that diacetyl can be used as a food ingredient during meat fermentation to control E. coli O157:H7 and Salmonella Typhimurium without harmful effects on the growth and acid production of P. acidilactici.

Animals↗
PubMed1999

Conventional and molecular methods for understanding probiotic bacteria functionality in gastrointestinal tracts.

The recent successes of probiotic application to limit colonization of foodborne pathogens in the gastrointestinal tracts of food animals ensures continued commercialization and widespread use of such cultures. Given that the the fermentation response and ecological balance of the probiotic consortium appears to be essential for the effectiveness of the cultures, it is essential to develop a methodology to accurately identify and quantitate these organisms during commercial production as well as successful in vivo colonization after administration. However, if further optimization of the effectiveness of defined cultures is to be achieved, methods to assess expression of key metabolic processes occurring during establishment of the probiotic culture as well as its subsequent ability to limit foodborne pathogen colonization are needed. Conventional methods to study individual probiotic gastrointestinal organisms include selective plating to identify specific nutritional groups, but the requirement of strict anaerobiosis for the obligate anaerobic members of these cultures can confound sample handling and preparation. Immunological methods can circumvent some of these problems but are somewhat limited for assessing functionality. The main advantage of using molecular tools is that the genetic diversity of the microflora, as well as their gene activity data are obtainable, both at the community level and at the single species level. Methods are currently available that permit studying individual members of microbial consortia, fluxes in community diversity, spatial distribution of consortia members, and the expression of specific microbial genes within communities. These methods involve the utilization of both DNA- and RNA-targeted probes, gene amplification protocols, and mRNA analysis. The study of mechanisms and functionality can only enhance the potential of probiotic cultures for limiting foodborne pathogen colonization.

Anaerobiosis↗
PubMed2004

Determination of toxicity of Campylobacter jejuni isolated from humans and from poultry carcasses acquired at various stages of production.

AIM: The research focused on the determination of the toxicity variation associated with Campylobacter jejuni isolated from humans and chickens. METHODS AND RESULTS: Campylobacter jejuni isolates were obtained from chicken carcasses and from humans exhibiting symptoms of campylobacteriosis. Using HeLa cells as the in vitro model, toxicity was determined for each isolate. The mean toxicity level of the chicken isolates was significantly lower than that of the human isolates (P < 0.001). There was a wide range of toxicity in C. jejuni isolated from chickens and the percentage of isolates exhibiting low toxicity remaining relatively constant. All C. jejuni isolates from humans possessed either medium or high levels of toxicity. CONCLUSIONS: All wildtype C. jejuni isolates obtained from poultry carcasses may not be equally important as a human foodborne pathogen. SIGNIFICANCE AND IMPACT OF STUDY: Campylobacter jejuni remains a primary foodborne pathogen and increased efforts are needed to determine the impact of wildtype isolates in causing human illness. The present research indicates that all isolates may not be equally important in regards to disease potential. The information found should be included in efforts to develop C. jejuni detection, control and infection modelling.

Animals↗
PubMed1998

Foodborne diseases. Emerging pathogens and trends.

The epidemiology of foodborne diseases is rapidly changing. In the past 15 years, new foodborne pathogens, such as Campylobacter jejuni and Escherichia coli O157:H7, have emerged as important public health problems. Well-recognized pathogens, such as Salmonella serotype Enteritidis, have increased in prevalence or become associated with new vehicles, and pathogens such as C. jejuni and S. Typhimurium are becoming increasingly resistant to antimicrobial agents. Evolving trends in foodborne diseases are being driven by the same factors that have led to the emergence of other infectious diseases: changes in demographic characteristics of the population, human behavior, industry, and technology and the shift toward a global economy, microbial adaptation, and breakdown in the public health infrastructure. Addressing emerging foodborne disease will require more sensitive and timely surveillance, enhanced methods of laboratory identification and subtyping, and identification of effective prevention and control strategies.

Bacterial Infections↗
PubMed2005

Relationship between consumer food safety knowledge and reported behavior among students from health sciences in one region of Spain.

A survey was conducted to investigate the relationship between knowledge about food safety and actual food handling practices among Spanish university students (mainly from the health sciences disciplines) who usually prepare meals at home. Based on level of education in food safety topics, students were divided in three groups: high, which included students from Food Science and Nutrition; medium, which included students from other health sciences; and low, which included students from non-health-related studies. More than two thirds of the 562 people selected had an accurate knowledge of the eight foodborne pathogens included in the survey, but only 5.2% were able to identify Staphylococcus aureus as a foodborne pathogen. Significant differences in responses were found depending on educational level concerning the food safety topic. For food handling, up to 60% of the responses reflected accurate knowledge of proper storage of prepared meals and washing of hands and materials to avoid cross-contamination. However, with the exception of questions related to storage temperature, there was considerable difference between knowledge and reported behavior. Although 98.6% of the participants recognized the importance of hand washing before and during food preparation, only one quarter (24.4%) affirmed that they washed their hands with soap and water. On questions concerning food practices, more accurate answers were given by the older students. Women answered questions regarding cross-contamination more accurately, whereas men were more accurate in response to questions concerning temperature and food preservation. In general, students with more knowledge of food hygiene had better reported practices, but even these students reported some high-risk behaviors. These results confirm the need to improve educational programs, ensuring that the acquired knowledge actually modifies consumer behavior.

Adult↗
PubMed1990

Public health and research perspectives on the microbial contamination of foods.

Scientific advances in methodology and epidemiology have resulted in a renewed awareness of foodborne disease, and increased contact among nations of the world has stimulated rapid global distribution of foods as well as foodborne pathogens. New food vehicles are being identified for old, familiar pathogens, and new pathogens are being discovered. Current research in food microbiology has spurred development of rapid and specific methods to identify these pathogens and to assess their virulence. Organisms of recent interest, such as Bacillus, Yersinia, Campylobacter, Listeria, Sporothrix, Giardia, Cryptosporidium, and Anisakis, are the foci of new investigations, as are the more familiar foodborne pathogens, Salmonella, Shigella, Clostridium, Staphylococcus, Entamoeba and Ascaris. Some foodborne organisms, such as parasitic protozoa, serve as hosts for unique bacterial and viral symbionts but also might become infected with mammalian viruses. The remote possibility of the transmission of human immunodeficiency viruses in foodborne protozoa is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Use of fluorescent microspheres as a tool to investigate bacterial interactions with growing plants.

Foodborne pathogens may exist as endophytes of growing plants. The internalization of Escherichia coli O157:H7 or other foodborne pathogens in growing lettuce plants may be independent of microbial factors. Mature lettuce plants were surface irrigated with E. coli O157:H7 or with FluoSpheres (fluorescent microspheres) and harvested 1, 3, and 5 days post-exposure. FluoSpheres were utilized as a bacterial surrogate. Microscopic examination of root, stem, and leaf tissue sections revealed that FluoSpheres were internalized into growing plants. Laser scanning confocal microscopy revealed that FluoSpheres were present within the root tissue and leaf stem tissue. The presence of FluoSpheres in internal portions of stem and leaf tissue suggests transport of the spheres from the root upward into the edible tissue. The level of uptake of FluoSpheres and E. coli O157:H7 was quantified using filtration. Numbers of FluoSpheres and E. coli O157:H7 cells in plant tissue were similar. The entry of E. coli O157:H7 into lettuce plants may be a passive event because the concentration of FluoSpheres was similar to that of the pathogen.

Bacterial Adhesion↗
PubMed2005

Fecal prevalence and diversity of Salmonella species in lactating dairy cattle in four states.

Salmonella is one of the most serious foodborne pathogenic bacteria in the United States, causing an estimated 1.3 million human illnesses each year. Dairy cows can be reservoirs of foodborne pathogenic bacteria, including Salmonella spp.; it is estimated that from 27 to 31% of dairy herds across the United States are colonized by Salmonella. The present study was designed to examine the occurrence of Salmonella spp. on dairies and to examine the serotypic diversity of Salmonella isolates on sampled dairies from across the United States. Fecal samples (n = 60 per dairy) were collected from 4 dairies in each of 4 states for a total of 960 fecal samples representing a total population of 13,200 dairy cattle. In the present study, 93 of 960 samples (9.96%) collected were culture-positive for Salmonella enterica. At least one Salmonella fecal-shedding cow was found in 9 of the 16 herds (56%) and the within-herd prevalence varied in our study from 0% in 7 herds to a maximum of 37% in 2 herds, with a mean prevalence among Salmonella-positive herds of 17%. Seventeen different serotypes were isolated, representing 7 different Salmonella serogroups. There were 2 or more different serogroups and serotypes present on 7 of the 9 Salmonella-positive farms. Serotypes Montevideo and Muenster were the most frequent and widespread. From our data, it appears that subclinical colonization with Salmonella enterica is relatively common on dairy farms and is represented by diverse serotypes on US dairy farms.

Animals↗
PubMed1998

Regulatory action criteria for filth and other extraneous materials. III. Review of flies and foodborne enteric disease.

Forty-seven species of flies have been reliably associated with filthy conditions that might allow the spread of foodborne pathogens. These are categorized as "filth flies." Of that 47, only 21 species represent a potential threat to human health as scientifically proven causative agents of foodborne myiasis or as carriers of enteropathogenic Escherichia coli, Salmonella, Shigella, and other foodborne pathogens. These 21 species are categorized as "disease-causing flies" based on strict scientific criteria. The criteria are association with E. coli, Salmonella, AND Shigella; synanthropy; endophily; communicative behavior; attraction to both excrement and food products; and recognition by authorities as a potential health hazard. Within Hazard Analysis and Critical Control Point and other U.S. Food and Drug Administration regulatory frameworks, disease-causing flies are contributing factors to the spread of foodborne disease that require preventive and corrective actions as appropriate under Sanitation Standard Operating Procedures, Good Manufacturing Practices, or pest control programs.

Animals↗
PubMed2000

A small outbreak of listeriosis potentially linked to the consumption of imitation crab meat.

A small outbreak of listeriosis involving two previously healthy adults occurred in Ontario. Food samples obtained from the refrigerator of the patients included imitation crab meat, canned black olives, macaroni and vegetable salad, spaghetti sauce with meatballs, mayonnaise and water. All of the samples except the water contained Listeria monocytogenes. The three most heavily contaminated samples were the imitation crab meat, the olives and the salad which contained 2.1 x 109, 1.1 x 107 and 1.3 x 106 cfu g-1, respectively. L. monocytogenes serotype 1/2b was isolated from the patients, as well as from the opened and unopened imitation crab meat. Molecular typing of the isolates by both randomly amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) typing demonstrated the imitation crab meat and clinical strains to be indistinguishable. Challenge studies performed with a pool of L. monocytogenes strains showed that imitation crab meat, but not olives, supported growth of the organism. In this study we have shown for the first time the potential involvement of imitation crab meat in a small outbreak of listeriosis. In terms of disease prevention, temperature control is critical to prevent or reduce the growth of this foodborne pathogen. In addition, with refrigerated products having a long (> 30 d) shelf life, additional safety factors must be used to prevent the growth of foodborne pathogens such as L. monocytogenes.

Animals↗
PubMed2002

Magnetized carbonyl iron and insoluble zirconium hydroxide mixture facilitates bacterial concentration and separation from nonfat dry milk.

A mixture of magnetized carbonyl iron and insoluble zirconium hydroxide was investigated for its ability to concentrate various foodborne pathogens from 25-ml samples of reconstituted nonfat dry milk. Each sample was artificially contaminated with 10(3) to 10(6) CFU/25 ml of representative foodborne pathogens (Salmonella enterica serovar Enteritidis, Listeria monocytogenes, and Bacillus cereus spores) and processed for bacterial concentration with high-speed centrifugation for the primary concentration followed by a secondary concentration step involving the carbonyl iron-zirconium hydroxide mixture. Bacterial recoveries, as evaluated on the basis of loss to discarded supernatants, exceeded 75% for all organisms at all inoculum levels and were usually >90%. Recovery was confirmed by direct plating of the immobilized pellet, for which the valueswere similar albeit more varied. Additional experiments confirmed that the magnetized carbonyl iron-insoluble zirconium hydroxide mixture was relatively nontoxic to both Salmonella Enteritidis and L monocytogenes Overall, the entire concentration scheme resulted in a 25-fold reduction in sample volume with the recovery of viable bacterial cells. This novel compound shows promise for facilitating inexpensive, rapid, and effective bacterial concentration in food systems.

Animals↗
PubMed1999

Foodborne infections during pregnancy.

The consequences of foodborne illness can be particularly devastating during pregnancy because both the woman and her fetus are at risk. Escalated production of progesterone during pregnancy leads to down-regulation of cellular (cell-mediated) immune functions. Many foodborne pathogens (and other pathogens) are intracellular pathogens, and infections caused by these pathogens are controlled by cell-mediated immunity. The pregnancy-induced decrease in cell-mediated immune functions leads to increased susceptibility of the pregnant woman to certain infections. Hepatitis E virus, Coxiella burnetii, Listeria monocytogenes, and Toxoplasma gondii are intracellular pathogens that have a predilection for the maternal-fetal unit and may induce serious disease in the mother and/or fetus. In the United States, T. gondii and L. monocytogenes are the most important foodborne pathogens in pregnancy, and these organisms can induce death or grave disease in the fetus and newborn. The pregnant woman, in order to protect herself and her fetus from the consequences of foodborne illness, must practice a high standard of food hygiene and personal cleanliness.

Female↗
PubMed1995

Microbiology of fresh and restructured lamb meat: a review.

Microbiology of meats has been a subject of great concern in food science and public health in recent years. Although many articles have been devoted to the microbiology of beef, pork, and poultry meats, much less has been written about microbiology of lamb meat and even less on restructured lamb meat. This article presents data on microbiology and shelf-life of fresh lamb meat; restructured meat products, restructured lamb meat products, bacteriology of restructured meat products, and important foodborne pathogens such as Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in meats and lamb meats. Also, the potential use of sodium and potassium lactates to control foodborne pathogens in meats and restructured lamb meat is reviewed This article should be of interest to all meat scientists, food scientists, and public health microbiologists who are concerned with the safety of meats in general and lamb meat in particular.

Animals↗
PubMed1998

rRNA stability in heat-killed and UV-irradiated enterotoxigenic Staphylococcus aureus and Escherichia coli O157:H7.

Differentiation of viable cells from nonviable cells is of considerable importance in the development of methods to detect foodborne pathogens. To study the suitability of 16S rRNA as an indicator of cell viability in nucleic acid-based detection assays, we examined rRNA stability in two representative foodborne pathogens, Escherichia coli O157:H7 and enterotoxigenic Staphylococcus aureus, which were inactivated by extreme heat, moderate heat, and UV irradiation. Cell death under all conditions was confirmed by a failure to grow in brain heart infusion broth after incubation for 48 h at 37 degrees C. rRNA stability was monitored by a Northern blot analysis, and detection was evaluated by using reverse transcription (RT)-PCR performed with two primer sets (which produced 325- and 1, 400-bp amplicons). rRNA of neither pathogen was detected by Northern blot analysis and RT-PCR after cells were killed by autoclaving at 121 degrees C for 15 min. In contrast, intact rRNA of both pathogens were detected by Northern blotting and could be amplified by RT-PCR up to 48 h after cells were killed by heat treatment at 80 degrees C and UV irradiation at 254 nm. rRNA was a suitable target molecule for monitoring bacterial viability under extreme heat conditions, but the presence of rRNA was not correlated with viability following moderate heat inactivation or UV irradiation of cells.

Blotting, Northern↗
PubMed1997

Chronic health effects of microbial foodborne disease.

The acute effects of foodborne disease are sometimes not the end of the illness. Several significant foodborne pathogens are capable of triggering chronic disease, and even permanent tissue or organ destruction, probably via immune mechanisms. Arthritis, septic and reactive, inflammatory bowel disease, haemolytic uraemic syndrome, Guillain-Barré syndrome, and possible several autoimmune disorders can be triggered by foodborne pathogens or their toxins. Research is needed to more fully understand the mechanisms by which the immune system is inappropriately activated by these common foodborne disease-causing agents.

Autoimmune Diseases↗
PubMed2006

Standardization of pulsed-field gel electrophoresis protocols for the subtyping of Escherichia coli O157:H7, Salmonella, and Shigella for PulseNet.

Standardized rapid pulsed-field gel electrophoresis (PFGE) protocols for the subtyping of Escherichia coli O157:H7, Salmonella serotypes, and Shigella species are described. These protocols are used by laboratories in PulseNet, a network of state and local health departments, and other public health laboratories that perform real-time PFGE subtyping of these bacterial foodborne pathogens for surveillance and outbreak investigations. Development and standardization of these protocols consisted of a thorough optimization of reagents and reaction conditions to ensure that the protocols yielded consistent results and high-quality PFGE pattern data in all the PulseNet participating laboratories. These rapid PFGE protocols are based on the original 3-4-day standardized procedure developed at Centers for Disease Control and Prevention that was validated in 1996 and 1997 by eight independent laboratories. By using these rapid standardized PFGE protocols, PulseNet laboratories are able to subtype foodborne pathogens in approximately 24 h, allowing for the early detection of foodborne disease case clusters and often aiding in the identification of the source responsible for the infections.

Cluster Analysis↗
PubMed1995

Immunochemical detection methods for Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes in foods.

Immunochemical assays should prove to be a significant improvement over standard culture methods for the detection of foodborne pathogens. These techniques take advantage of the specificity and sensitivity of the antibody/antigen reaction for analyte detection. ELISA is the most useful form of immunochemical method for the detection of foodborne pathogens in the food-processing setting, based on their simplicity and ability to analyze large numbers of samples at a time. Concerns with immunochemical techniques include problems with cross-reactivity and difficulties obtaining species specific assays. Also, most immunochemical methods continue to require an enrichment technique; however, subsequent identification is quite rapid when compared with standard culture methods, therefore allowing for the quicker release of negative products.

Culture Media↗