Food processing and production

• what is primary processing?

  processing crops or other harvested food to produce ingredients for dishes
• What is secondary processing?

  processing ingredients into food products
• What are some examples of primary processing?

  - milling wheat into flour

  - heat treatment of milk

  - pasteurised, UHT, sterilised and micro-filtered milk
• What are some examples of secondary processing?


  - flour into bread

  - flour into pasta

  - milk into cheese and yogurt

  - fruit into jams
• How is flour milled?

  - it is harvested and then kept in dry storage

  - grain passed through steel rollers to grind them up and produce flour

  - sieves are sued to separate the different kinds of flour
• How is milk pasteurised?

  - also called high temperature short time pasteurisation

  - milk is heated using a heat exchanger to 72 degrees for 15 seconds

  - it is then cooled to under 10 degrees

  - has very little effect on the sensory or nutritional value of the milk
• How does UHT work?

  - milk is heated to 132 degrees for 1 second

  - it is then quickly cooled and packed in special multi-layered storage packs

  has a minimal effect on sensory and nutritional values of milk. some B12 may be lost after storage
• How is milk sterilised?

  - milk is put in special sealed glass bottles

  - heated to 110 degrees for 30 minutes

  - it can then last for several months at ambient temerature

  - causes milk to darken in colour and change flavour. some proteins are denatures and lots of B1 and B12 are lost
• How is milk micro-filtered?

  - micro filters remove almost all bacteria, not just pathogenic ones

  - it is filtered and then homogenised and pasteurised as usual

  - the shelf life is increased, but it still must be kept between 0 and 5 degrees
• What foods are fortified?

  - thiamin, niacin, calcium and iron added to white flour

  - folic acid and iron added to breakfast cereals

  - vitamin A and D added to fats and low fat spreads
• What are possible issues with added colourings, flavourings and preservatives?

  - colourings can make some children hyperactive

  - flavourings such as salt may have adverse effect on health

  - people become use to very intense flavour, which may deter them from eating more natural foods

  - preservatives can cause allergic reactions in some people