Cooking Ingredients Research Articles

The microbiology of mixed salad containing raw and cooked ingredients without dressing

Growth of aerobic mesophilic bacteria in mixed salad without dressing, containing cooked sweet corn and raw endive, was similar to that of raw endive alone. At 9°C, sweet corn permitted the growth of the lactic acid bacterium Leuconostoc mesenteroides, whenever the bacterium was present on raw endive, whereas no growth of lactic acid bacteria was recorded on raw endive alone. Listeria monocytogenes, artificially inoculated in the samples, grew more in the mixed salad than in the raw endive alone, for products stored at 6°C and 9°C. Acidification of sweet corn to pH 5.0 was proposed to reduce the development of L. monocytogenes in the mixed salad to a level similar to that recorded in the raw endive alone. Acidification with citric acid reduced spoilage of sweet corn, whereas acetic acid caused necrosis on the leaves of raw endive.

Human diets cooked by microwave or conventionally: Comparative sub-chronic (13-wk) toxicity study in rats

To compare the possible effects of microwave and conventional cooking on a range of common dietary components, mixed human diets containing beef, potatoes and vegetables were fed to groups of 10 male and 10 female Wistar rats for 13 wk. The diet ingredients were cooked by either of the methods in a normal and an abused manner, the latter consisting of the normal treatment followed by two cycles of reheating to approximately 85°C and cooling. The cooked ingredients were freeze-dried, ground and mixed with supplements of vitamins and minerals to meet the rat requirements. An additional control group was fed a cereal-based rodent diet. Criteria to assess toxicity included clinical observations, ophthalmoscopy, growth, food and water intake, haematology, clinical chemistry, urinalysis, organ weights, micronucleated erythrocytes in bone marrow, gross examination at autopsy and microscopic examination of a wide range of organs. The results indicate no adverse effects of the diets cooked by microwave compared with those cooked conventionally.

A large outbreak of foodborne salmonellosis on the Navajo Nation Indian Reservation, epidemiology and secondary transmission.

In September 1974, the largest outbreak of foodborne salmonellosis ever reported to the Center for Disease Control--affecting an estimated 3,400 persons--occurred on the Navajo Nation Indian Reservation. The responsible agent was Salmonella newport and the vehicle of transmission was potato salad served to an estimated 11,000 persons at a free barbecue. The cooked ingredients of the potato salad had been stored for up to 16 hours at improper holding temperatures. The magnitude of the outbreak allowed us to study secondary transmission by calculating the rates of diarrheal illness during the 2 weeks following the outbreak in persons who did not attend the barbecue and by examining the results of stool cultures obtained after the outbreak. We found no secondary transmission. We conclude that a health official should monitor food preparation and service at large social gatherings and that person-to-person transmission of salmonellosis probably does not normally occur even in settings considered highly conductive to cross-infection.