food spoilage, contamination, poisoning Flashcards
What are the causes of food spoilage and can you give a description of them? (6)
- microorganisms - bacteria, moulds, yeasts, fungi
- enzymes - speed up the process of decay to enable bacteria to absorb nutrients and reproduce
- insects and rodents - leave behind bacteria, urine and faeces
- chemical reactions - the reactions between the food, oxygen and moisture
- environmental factors - such as warmth, pH, oxygen, and moisture
- time - the speed of spoilage is determined by hygiene, correct storage and temperature
define autolysis
self destruction, caused by enzymes present in the food
define microbial spoilage
caused by the growth of micro-organisms e.g. bacteria, yeasts and moulds
what is pathogenic bacteria
harmful bacteria
define cross-contamination
the transfer of bacteria from one source to another. usually raw food to ready to eat food but can also be the transfer of bacteria from unclean hands, equipment, cloths or pests.
What is the role of environmental health officers (EHO’S)?
they monitor all food businesses to check that food safety regulations are being followed.
What happens if EHO’S find poor food safety?
the business will be warned, fined, or jailed depending on how serious the problem is
why does the correct temperature play an important part in food spoilage?
correct temperatures play an important part because they will help slow down bacterial growth and food spoilage
what temperature should each of the following be stored at?
chilled foods, frozen foods, ambient foods, hot held foods.
chilled foods - fridge 0-5 degrees Celsius
frozen foods - freezer -18 degrees Celsius
ambient foods - stored on a shelf or cupboard at room temperature
hot held foods - 63 degrees Celsius
what type of conditions do bacteria need to grow and multiply?
bacteria need warm conditions to grow and multiply
what’s the ideal temperature for bacterial growth?
30-37 degrees Celsius
what is the bacterial growth danger zone?
5-63 degrees Celsius
what happens to bacteria at very cold temperatures?
bacteria become dormant and cannot grow or multiply - but do not die
at what temperature are most bacteria destroyed?
63 degrees celsius
what are the three main ways food can deteriorate and can you explain what happens during it?
ripening - this will continue until he food as become inedible e.g. banana ripening
browning - enzymes can react with air causing certain foods to discolour e.g. apples
oxidation - loss of nutrients, such as vitamin C from food, e.g. over boiling green vegetables
define the term bacteria
single celled micro-organisms which are present naturally in the environment
define the term yeast
single celled fungi
define term mould
fungi which grow as filaments on food
what are the three ways food can become contaminated?
bacterial, chemical and physical
give an example of chemical contamination
chemicals fro the farm, cleaning products used in the processing plant and fly spray used in the kitchen
give an example of physical contamination
soil from the ground when harvesting , a loose bolt from a processing plant when packaging, a hair from a chef in the kitchen
give an example of bacterial contamination
bacteria can be transferred onto food through cross-contamination, via equipment, people or pests, or can be naturally present in the food.
some bacteria can produce toxins which can cause food poising.
state the conditions micro-organisms need to survive
temperature, moisture, food, time, oxygen, pH level
name high risk foods
meat, dairy, eggs, shellfish and seafood, prepared salads and vegetables, cooked rice and pasta
