Food poisoning is frequently caused by bacteria from food that has been poorly handled, stored or cooked.
Symptoms of food poisoning can include nausea, stomach cramps, diarrhoea, fever, and headaches. Symptoms can occur within 30 minutes of eating, or a number of hours or days later. They can be mild or severe.
Some bacteria can also cause other symptoms. Listeria bacteria may cause miscarriage or other serious illness in susceptible people. Certain people are more at risk from food poisoning. This includes young children, pregnant women, the elderly, and people with other illnesses.
Bacteria in food
Food-poisoning bacteria are often naturally present in food and can multiply quickly under the right conditions. It is very important not to give bacteria the conditions under which they multiply rapidly. Bacteria are everywhere – in the soil, on animals, on people and on the things people touch and use – but they are mostly harmless.
However, some bacteria cause food-borne illness, and it is possible for foods, such as meat or vegetables, to contain food-poisoning bacteria from the start or to be contaminated at a later stage.
During food preparation
Hands and equipment (such as knives and cutting boards) can be contaminated with bacteria from raw food. It is important to wash hands and tools properly to reduce the likelihood of food becoming contaminated with bacteria.
Bacteria from raw food can contaminate ready-to-eat or cooked foods if they are stored in such a way that they come into contact with each other. This includes contact between raw food juices and cooked or ready-to-eat foods.
The food poisoning chain
There must be a chain of events for food poisoning to occur:
- There must be bacteria on the food
- The bacteria must have the right conditions to grow – that is warmth (between 5°c and 60°c), moisture and food
- The bacteria must have time to grow and multiply.
By preventing each of these, the food-poisoning chain will be broken and food handlers ensure that food poisoning is prevented.