Distribution of Enterotoxin- and Epsilon-Positive Clostridium perfringens Spores in U.S. Retail Spices.

The role of spices as vehicles of foodborne illness prompted an examination of bacterial spores in these products. Here, we report on the levels and characteristics of spores of Clostridium perfringens associated with 247 U.S.

Spore prevalence and toxigenicity of Bacillus cereus and Bacillus thuringiensis isolates from U.S. retail spices.

Recent incidents of foodborne illness associated with spices as the vehicle of transmission prompted this examination of U.S. retail spices with regard to Bacillus cereus.

Inhibition of foodborne pathogens by pomegranate juice.

Pomegranates have health-promoting benefits because of their polyphenol constituents. Previous studies have demonstrated the antimicrobial activity of aqueous and organic extracts of pomegranate components and by-products. We sought to determine the antimicrobial activity against 40 foodborne pathogens representing eight bacterial species using juice itself.

Growth of enterotoxigenic Bacillus cereus on salmon (Oncorhynchus nerka).

We previously demonstrated the widespread presence of enterotoxigenic Bacillus cereus in marine foods. In view of the widespread consumption of raw fish, we sought to determine the ability of this organism to grow on the surface of wild Alaskan salmon at abusive temperatures (12, 16, and 20°C), using an isolate able to produce elevated levels of hemolysin BL enterotoxin and nonhemolytic enterotoxin. An incubation temperature of 37°C for colony formation was found to be selective for B.

Inhibitory potential of tea polyphenolics and influence of extraction time against Helicobacter pylori and lack of inhibition of beneficial lactic acid bacteria.

Tea polyphenolics such as catechins are known to have the potential to inhibit many bacterial pathogens. Helicobacter pylori has been identified as an etiologic agent in the development of gastric ulcer, peptic ulcer, gastritis, and many other stomach-related diseases. In this study, we investigated the effect of 9 tea extracts--3 different brands representing 4 different processed types (white, green, oolong, and black)--on the inhibition of H.

Physical characteristics of spores of food-associated isolates of the Bacillus cereus group.

All 47 food-borne isolates of Bacillus cereus sensu stricto, as well as 10 of 12 food-borne, enterotoxigenic isolates of Bacillus thuringiensis, possessed appendages. Spores were moderately to highly hydrophobic, and each had a net negative charge. These characteristics indicate that spores of food-associated B.

Survival during cooking and growth from spores of diarrheal and emetic types of Bacillus cereus in rice.

Bacillus cereus is a gram-positive, spore-forming, facultative anaerobe that is responsible for two types of gastrointestinal diseases: emesis and diarrhea. A significant difference in the D(95 degrees C)-values of spores of the emetic and the diarrheal types was initially determined. A mixture of B.

Detection of toxigenic Bacillus cereus and Bacillus thuringiensis spores in U.S. rice.

Bacillus cereus is a gram-positive, endospore forming pathogenic bacterium that is ubiquitous in the environment and is frequently associated with emetic and diarrheal types of foodborne illness. In this study, 178 samples of raw rice from retail food stores were analyzed for the presence of B. cereus spores.

Stress proteins of Clostridium perfringens type A immunoreact with antiserum from rabbits infected with gas gangrene.

Various stressors were used to induce stress proteins in Clostridium perfringens. Cultures of C. perfringens FD-1041 were subjected to cold shock (28 degrees C for 1 h), acid shock (pH 4.

Enterotoxigenicity and genetic relatedness of Clostridium perfringens isolates from retail foods in the United States.

Clostridium perfringens is a leading cause of bacterial food-borne illness in countries where consumption of meat and poultry is high. For example, each year in the United States, this organism is the second or third most common cause of confirmed cases of food-borne illness. Surveys of the incidence of this organism in retail foods were done in the 1960s without regard to whether isolates were enterotoxigenic.

Elevation of the Heat Resistance of Vegetative Cells and Spores of Clostridium perfringens Type A by Sublethal Heat Shock.

The degree of heat resistance conferred on Clostridium perfringens by a heat shock, the kinetics of this development, and its duration were determined. A sublethal heat shock at 55°C for 30 min increased the heat tolerance of vegetative cells at least two- to threefold. The acquired tolerance was maintained for 2 h after the heat shock treatment.

Lack of Correlation between the Enterotoxigenicity of Clostridium perfringens Isolates and Propionic Acid Formation or Amylase Activity at 46°C.

The absence in the supernatant fluid of either extracellular amylase in cultures grown at 46°C or propionic acid has been proposed for the presumptive identification of enterotoxin-positive strains of Clostridium perfringens . However we found that propionic acid was formed by several enterotoxin-positive, as well as enterotoxin-negative, strains of this organism. In addition 4 of 13 ent stains produced extracellular amylase during growth at 46°C.

Enumeration and Confirmation of Clostridium perfringens.

A number of media have been proposed for the enumeration and confirmation of Clostridium perfringens in food and water. Most of these employ sulfite and iron together with selective antibiotics. This report discusses these various media and conditions for their use.

Evaluation of Plating Media for Recovery of Heated Clostridium perfringens Spores.

Four selective and eight non-selective plating media were evaluated for their ability to enumerate six strains of heat-activated and heat-injured spores of Clostridium perfringens . Trypticase-sulfite-neomycin (TSN) agar and sulfite-polymyxin-sulfadiazine (SPS) agar gave higher counts of heat-activated spores than non-selective media. In the case of heat-injured spores, wide variation in recovery was obtained depending on strain and medium.