Food poisoning can be caused by:
- Bacteria
- Chemicals and metals
- Poisonous plants
Bacteria
Bacteria are microbes, which are found everywhere. Most bacteria are not harmful and some are essential to food production, for example yogurt and cheese. Food spoilage bacteria will cause food to rot but they do not usually cause food poising.
Only a few of the bacteria around us are harmful. These are called pathogenic bacteria and cannot be detected by any changes in the taste or smell of food. An important part of quality assurance in food production is a system, which will protect the consumer from food poisoning by controlling the growth of bacteria.
Bacteria that are a common hazard in food product are:
- Salmonella
- Clostridium Perfringers
- Escherichia coli
- Staphylococcus Auruus
- Listeria
Foods can be infected with micro-organisms at any stage of food production. Micro-organisms multiply rapidly in conditions which have warmth, moisture, food and time.
Foods are categorised according to their risk against micro-organism growth.
To reduce the risk o cross-contamination different coloured chopping boards and knives are used during food preparation:
Types of food Poising
Diagram of a Thermometer
Summary
- Cold food must be stored at 0-5˚C.
- Cooked food, particularly high risk foods must reach a core temperature of 72˚C for two minutes and not cool down below 63˚C.
- Bacteria do not die when chilled or frozen.
Activity
1)).When a new food worker starts their job for the first time they would have to know…
- What they need to know when they arrive for their first day at work.
- What they wear for work
- When and how often they wash their hands
- As soon as the employer arrives to work they would have to need to…
- Learn about personal hygiene
- Learn about how to clean the equipment
- Know about the quality control system
- Their dress code would be to…
- Wear a hair net
- Wear gloves to work in or wash hands properly
- Not wear any make-up, perfume, aftershave and jewellery
- Wear special footwear e.g. Wellingtons
- They would have to wash their hands after…
- Going to the toilet
- Blowing your nose
- Having a break
- Working with raw ingredients particularly high risk foods
- Coughing, or touching your face or hair.
- How often do you clean the…
- Taps and hand basins = daily bases
- Walls = weekly basses
- Floors = daily basses
- Slicing machines = after every task
- Food utensils such as knives and spoons = after every task
Sauces
Sauces are used to add colour, flavour, moisture and nutritional value to food. There are many types of sweet and savoury sauces. The properties and characteristics of each sauce will depend on the ingredients and how it is made.
Sauces can be thickened in the following ways:
- By adding starch (white sauce or custard)
- By using a puree of fruit (apple sauce, raspberry sauce) or vegetables (tomato or onion)
- By using eggs (egg custard)
Thickening of sauces
Many sauces can be thickened by adding starch. These can include adding wheat flour, corn four or arrowroot to a liquid. These thicken when heated by a process known as gelatinisation.
What is Gelatinisation?
Gelatinisation occurs when a starch granule is heated in water. Water molecules become hydrogen bonded to the starch molecules resulting in a smooth, jelly-like texture. As more water is absorbed the granules swell and movement is restricted, increasing the thickness (viscosity) of the mixture.
Thickening Agents used in Sauces
Flour
- Granules of flour in starch burst open at boiling point and spread.
- Whisking them distributes the granules through the sauce, causing it to thicken.
- Flour is normally cooked with some sort of fat before any other ingredient is added. This will avoid an uncooked, floury flavour.
Corn flour
- Corn flour is pure starch and thickens sauces very effectively and gives a different texture than normal flour.
- Corn flour must be mixed with cold water it is added to any hot liquid or it will go lumpy.
Arrowroot
- Arrowroot is an edible starch from a root and is used for clear glazes and unlike corn flour, it will thicken fruit juices.
- Arrowroot must be ‘slaked’ first. This means it must be mixed with cold water first.
Egg
- Eggs are one of the most difficult thickeners as egg based sauces will curdle if overheated.
- Eggs are used to thicken hollandaise sauces and mayonnaise
Purees Vegetables/Fruit
- When you puree fruit or vegetables in sauce, it will thicken.
Types of Sauces
The main types of sauces are Roux and All-in-One.