• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Food Preservation.

Extracts from this document...


Food Preservation a) Canning The idea of canning is that it destroys any micro-organisms and their spores by applying heat. This is achieved by sterilising food within airtight containers to prevent re-contamination. The basic stages of canning are: * Filling the cans with product * Sealing the cans * Washing the cans * Sterilising the cans * Cooling the cans Food products that have been canned have very long shelf life and are stored at room temperature. b) Freezing Freezing is based on two ideas. Firstly, very low temperatures which inhibit growth of micro-organisms and reduce enzyme and chemical activity, and secondly the formation of ice crystals which draw available water away from food, therefore preventing the growth of micro-organisms. ...read more.


The product is scraped against a cooled surface and then immediately scraped away. iii. Cryogenic freezing: Liquid nitrogen (or CO2) is sprayed directly onto small food items such as soft fruits or prawns. It is due to the liquids' extremely low temperatures, -196oC and -78oC, which make freezing as a result almost instant. c) Drying Micro-organisms need water in order to grow and multiply. When moisture is reduced in food, micro-organism growth is reduced. Dehydration reduces the water activity level, weight and bulk of the food and helps to preserve the product. Dehydration is the reduction of water to prevent micro-organism activity. Many products, such as vegetables, are diced before drying - to increase their surface area - making water loss more rapid. ...read more.


This process is most commonly used to inhibit sprouting of vegetables, delay ripening of fruits or reduce numbers of micro-organisms which cause food poisoning. e) Chemical Preservatives This includes; Pickling Pickling vegetables and fruits with vinegar prevents the growth of micro-organisms. This is due to the food being placed in a low pH solution in which micro-organisms cannot grow. Sugar and Salt The addition of large quantities of sugar inhibits the growth of micro-organisms by making water unavailable. Jams, marmalades and jellies use this principle in their manufacture. Coating food in salt or placing it in a salt solution (brine) reduces the moisture content of the food, i.e. it reduces the availability of water to micro-organisms. With little moisture, micro-organism growth is reduced. However, the taste of the food may well be changed as a consequence. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Food Technology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Food Technology essays

  1. Explain the need for nutrition by living organisms.

    IDENTIFY THE SOURCES AND TYPES OF MATERIALS EXCRETED AND EXPLAIN THE NEED FOR EXCRETION. Excretion is a process whereby metabolic wastes are removed from the body. These include by-products of digestions; waste materials from tissue repair and excess water and salts, carbon dioxide from respiration and nitrogenous compounds from the break down of proteins and urea.

  2. Chocolate: Behind its bad rap

    * The vast majority of evidence suggests we dismiss the hypothesis that chocolate is a significant migraine trigger. * Chocolate has relatively little impact when it comes to causing dental caries. Chocolate tends to clear the mouth quickly, limiting the time it is in contact with the teeth.


    Now I will explain a few problems caused by changing food and eating habits Obesity- Fast Food, Obesity's biggest culprit Trend in Fast food Obesity: The Center for Health and Health Care in Schools reports dramatic increase in consumption of fast food by children since 1970.


    These actions result in the inhibition of protein or nucleic acid biosynthesis and uncoupling of electron transport from active transport of thiomethyl-�-D-galactoside and potassium. The loss of these ions has been implicated as the primary cause of cell death. The bactericidal activities of enterocoliticin and serracin P have been shown

  1. Bacterial Food Poisoning

    Hot foods should be served immediately or held above 140 degrees F. When refrigerating large volumes of gravies, meat dishes, etc., divide them into small portions so they will cool rapidly. The food should be reheated to 165o F. prior to serving.

  2. Conditions in Japanese Prisoner of War Camps In WorldWar II

    Around camp Cabanatuan #1, fruit lay rotting on the ground yet the commandant refused to allow prisoners on pain of death to harvest the abundance of fruit growing on the trees outside the camp. At Cabanatuan, Chaplain Taylor organized an entire smuggling ring to obtain medicine and food for hospital patients.

  1. Fast-food Industry Analysis

    how are companies differentiated. Basically all companies offer same services and products through their signature style hamburgers, such as The Big Mac, Six-Dollar Burger, The Whopper, The Famous Star, and The Sourdough Jack. In addition, many produce a variety of items such as chicken sandwiches, fries, frosties, soft drinks,

  2. Globalisation and regulation of food risks. A theoretical overview.

    Food consumption is for an important part based on self provision and only specific products are bought on markets and in small shops. For example most people had a few chickens around the house for eggs and meat. A certain separation between food producers and food consumers is however already

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work