Food Spoilage Flashcards
Food Spoilage
As soon as a food is harvested slaughtered or processed it begins to change. This is because of Autolysis - self destruction caused by the enzymes present in the food and Microbial spoilage - caused by the growth of microorganisms.
Food Spoilage: Autolysis - Enzymes
Enzymes are chemicals that cause food to deteriorate in three ways: Ripening - This will continue until the food becomes inedible. Browning - Enzymes can react with air causing certain foods to discolour. Oxidation - Loss of nutrients such as vitamin C from food.
Food Spoilage: Microbial spoilage
Spoilage can be caused by the growth of: bateria - single celled micro-organisms which are present naturally in the environment. Yeasts such as fungi. Moulds which is fungi which grows in food.
Food Contamination
Food contamination can lead to food poisioning in three ways: bacterial and chemical and physical.
Physical Contamination
Physical contamination can occur in a variety of ways at different stages of food processing and production such as soil from the ground when harvesting.
Bacterial Contamination
Most bacteria are harmless and only a small number can cause illness called pathogenic bacteria. Food that is contaminated can look taste and smell normal. Bacteria can be transferred onto food through cross contamination via equipment or people or pests.
Micro-organisms
Micro-organisms need conditions to survive and reproduce such as temperature or moisture or food or time or oxygen levels.
Temperature
Bacteria need warm conditions to grow and multiply. Ideal temperature is 30-37C. Most bacteria are destroyed above 63C. Bacterial Growth danger zone is 5C to 63C.
Moitsure
Where there is no moisture bacteria cannot grow. However bacteria and moulds can produce spores which can survive until water is added to the food.
Food
Bacteria need a source of food to grow and multiply: these food are usually high in moisture and fat and protein and may be ready to eat. Food where bacteria can multiply rapidly are high risk foods such as meat or dairy products etc.
Time
Given the right conditions - one bacteria can divide into two every 10-20 minutes.
People at high risk of food poisoning
Elderly people. Babies. And anyone who is ill or pregnant needs to be extra careful about the food that they eat.
Symptoms of food poisoning:
Most common symptoms are: Feeling sick or being sick or abdominal pain.
Campylobacter
Sources: Raw and undercooked poultry and unpasteurised milk and contaminated water. Signs and symptoms include: Fever or headache or dizziness for a few hours followed by abdominal pain.
E-Coli 0157
Sources: Raw and undercooked meat and poultry. Unwashed vegetables. Contaminated water. Signs and symptoms: Diarrhoea which may contain blood can lead to kidney failure or death.
