2. Objectives How food contamination occurs Why food contamination occurs Identify stages of food preparation where food spoilage occurs Describe and apply safe practices in stages of food preparation
4. Food Contamination Food poisoning occurs when food is not prepared or cooked safely. Some symptoms of food poisoning are vomiting, diarrhoea and fever. Food can be contaminated by physical means, microbiological modes and enzymatic action.
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6. Temperature of Food Temperatures ranging from 4 to 60 degrees Celsius favour bacteria growth. Bacteria is killed at 100 degrees Celsius and inactive at -18 degrees Celsius. Hot food should hence be kept hot and cold food be kept cold so that bacteria is destroyed and bacteria does not grow.
7. Presence of Moisture Micro-organisms require moisture to grow and would multiply quickly when moisture content is high. People handling food with high moisture content can cross-contaminate micro-organisms from unclean hands. Examples of food with high amounts of moisture are raw meat, seafood, vegetables and fruits.
8. Presence of Insects Insects and their droppings carry many micro-organisms that are invisible to humans. When they get in contact with food, the area would be contaminated with bacteria and become unhygienic.
11. Enzymatic Action Enzymes are substances found naturally in animals and plants. Enzymes of humans help break down food into simpler forms. Enzymes of bacteria in raw food help liquefy the food to produce a slimy coating that causes food to spoil faster. However, enzymatic action only affects the appearance of the food.
13. Food Spoilage Food spoilage can occur anytime such as during food handling, food preparation and food storage. Wrong practices at any stage can introduce micro-organisms into the food.