Science aid: Food and disease

Milk

Milk is very vulnerable to contaminination during collection and storage, and is an excellent medium for growth.

The flash pasteurisation method is the most common for destroying any micro-organisms. Milk is heated to 72^o C for 15 seconds, then rapidly cooled to 3^oC

The heat kills many pathogens and the rapid cooling prevents those resistant to heat from divinding rapidly. The milk now must be kept refridgerated and can last for several days. The flash pasteurisation process does not effect the flavour or nutritional value of milk.

Salmonella and Food Poisoning

Escherichia coli (E-Coli) and Salmonella are two of the most prolific pathogens responsible for food poisoning.

The spread of Salmonella can result from the way that animals are reared. Chickens reared for meat production usually live in a large building with the floor covered in wood shavings. This can become very contaminated with droppings that may contain salmonella that spreads to other chickens.

Food poisoning by Salmonella can be avoided by:

Improving the chicken's living conditions so that Salmonella does not spread between them.

Before use, the chicken should be kept frozen and kept separate from other meats and juices kept from mixing with other foods.

The chicken must be defrosted thouroughly before cooking; if done in open it needs to be covered to prevent flies, dust, and bacteria reaching it.

Cook the bird all the way through so the juices run clear.

Do not eat raw eggs or untreated milk!