Causes of food poisoning

Pathogens such as Salmonella, Campylobacter and E. coli may be found in our food-producing animals. Care in processing, transport, storage, preparing and serving of food is necessary to reduce the risk of contamination.
Food poisoning bacteria can multiply very quickly, particularly in certain conditions. The factors that affect bacterial growth include:

• Time – in ideal conditions, one bacterium can multiply to more than two million in seven hours.
• Temperature – food poisoning bacteria grow best in the temperature range between 5 °C and 60 °C. This is referred to as the ‘temperature danger zone’. This means that we need to keep perishable food either very cold or very hot, in order to avoid food poisoning.
• Nutrients – most foods contain enough nutrients for bacteria to grow. This is especially the case with potentially high-risk foods such as dairy and egg products, meat and poultry and seafood.
• Water – bacteria need water for their growth. Without water, growth may slow down or stop. That is why dried foods do not spoil.
• pH – is the measure of acidity or alkalinity and is also important for controlling bacterial growth. Low pH (acid conditions) generally stops bacterial growth, but where the pH of food is neutral, as is the case for many foods, most bacteria grow quite well.

Source: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Food_poisoning_how_to_prevent_it