Microbial Pathogens in Fresh Produce -- the Regulatory Perspective.

The potential for microbial contamination of fruits and vegetables is high because of the wide variety of conditions to which the produce is exposed during growth, harvest, and distribution. Heat treatment may also destroy the protective barriers (peels, husks, rinds) of fruits and vegetables, permitting the entry of microbial pathogens into the produce and providing them access to nutrients essential for their growth and proliferation. Proper refrigeration, storage, and shipping conditions as well as removal of soil from fresh produce by washing with chlorinated water are recommended to prevent contamination.

Growth of Salmonella enteritidis in Yolk of Shell Eggs from Normal and Seropositive Hens.

The growth of Salmonella enteritidis inoculated into the yolks of shell eggs from normal and seropositive hens was determined at various temperatures. All eggs were inoculated with approximately 1 colony-forming unit (CFU)/g of yolk. In eggs from normal hens, the organism multiplied with a generation time of 25 min, reaching a density of about 10 CFU/g in 12 h at 37°C.

Campylobacter jejuni and Campylobacter coli Production of a Cytotonic Toxin Immunologically Similar to Cholera Toxin.

An enzyme-linked immunosorbent assay (ELISA) based on binding to cholera toxin (CT) antibody was used to screen cell-free supernatant fluids from 11 strains of Campylobacter jejuni and one strain of Campylobacter coli . Positive results for seven of the eight clinical isolates as well as for one animal and one food isolate suggested that these strains produced an extracellular factor immunologically similar to CT. An affinity column (packed with Sepharose 4B conjugated to purified anti-CT IgG via cyanogen bromide) was used to separate the extracellular factor from cell-free supernatant fluids.