Ideal environment for Staphylococcus aureus

Although extremely well suited to live on humans, Staphylococcus aureus is also found in a variety of other habitats, including water, decaying matter, and on just about any surface. Staphylococcus aureus is extremely durable. It grows in a wide temperature range of other habitats, including water, decaying matter and on just about any surface.

The major sources of energy for Staphylococcus aureus are carbohydrates and amino acids. It can grow in a temperature range of 10°C-45°C, with an optimum temperature between 30°C–37°C. The pH range of growth is 42–93, with the optimum range of 7.0–7.5

In foods, Staphylococcus aureus will grow at temperatures as low as 6.7 °C and as high as 44.4 °C. In some foods (Turkey stuffing), temperatures as high as 48.9 °C have sometimes been necessary to destroy the organism.

To keep the risk of staphylococcal food intoxication as low as possible, the holding temperatures of ready-to-eat food must be kept above 48 °C. Because other foodborne pathogens (such as Bacillus cereus) can grow at even higher temperatures, the general recommendations to keep ready-to-eat food warm is a holding temperature of more than 65 °C.
Ideal environment for Staphylococcus aureus  

Temperature 40°F and below inhibits the growth of Salmonella

Salmonella is the most common form of food poisoning, causing vomiting, fever, and stomach pain. There re actually three types of disease caused by Salmonella: Enteric fever caused by S. typhosa; septicemia caused by S. cholerasuis; and gastrointeritidis caused by S typhimurium and S. enteritidis.

Salmonellae in foods are destroyed by heating the food to at least 160° F for red meats and 185° F for poultry. In general, foods heated to an end-point temperature of 160°F or above will destroy Salmonella.

All foods should be held at temperatures of 4.4 °C or below when not being cooked, prepared for cooking or being served. This would not eliminate Salmonella organisms from foods, but it would prevent their growth in the foods so that their number would be too small to cause salmonellosis in healthy adults.
Temperature 40°F and below inhibits the growth of Salmonella

Shigella association with Foods

Shigella association with Foods
The principal foods involved in Shigella outbreaks were a variety of salads and seafood which became contaminated during handling by infected workers.

This was frequently coupled with improper refrigeration. After the initial infection from contaminated food, the disease readily spreads from person to person by the fecal-oral route of transmission.

Shigellas usually are considered to be relatively fragile; i.e., they do not survive well outside the host. Like most other members of the family Enterobacteriaceae, they are readily killed by most heat treatments employed in the processing and preparation of foods, and do not survive well at pH below 4.5.

However, studies on the survival of Shigella suggest that under certain selected conditions, they can survive for extended periods in foods.

For example, Shigella sonnei and Shigella flexneri have been reported to survive at 25 degree C (77 degree F) in flour and in pasteurized whole milk for more than 170 days; in eggs, clams, and shrimp for more than 50 days; and in eggs whites for more than 20 days.

At lower temperatures such as -20 degree and 0.5 degree C survival for longer periods has been reported.

Laboratory data suggest that Shigella may survive for extended periods on foods and may grow under selected conditions. However, in practice, shigellae are rarely isolated from processed products.

Manufacturers do not routinely test their products, raw materials or processing environment for Shigella, and there is no evidence to suggest that routine testing is warranted.

Most outbreaks result from contamination of raw or previously cooked foods during preparations in the homes or in foodservice establishments. Generally, the source of contamination can be traced to a carrier whose personal hygiene is poor.
Shigella association with Foods