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Overview of food preservation technology

Food preservation helps to deliver the food product to consumers at the best possible value for consumption

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Overview of food preservation technology

  1. 1. Overview Of Food Preservation Technology Presented By, CHINMAI R DASTIKOP UNIVERSITY OF AGRICULTURAL SCIENCE DHARWAD 1
  2. 2. Content  What is Food Preservation?  Why is Food Preservation important?  Principles of Food Preservation  Methods  Safety of preservation methods 2
  3. 3. Food Preservation  Food preservation involves number of different methods to preserve/store the food without spoilage/contamination by microbes.  It tends to increase the shelf life of the product.  This technology of food preservation helps to deliver the food product to consumers at the best possible value for consumption.  Different kinds of foods require different methods of preservations based on the type, composition, method of preparation, moisture content etc.  The main objective of food preservation to avoid spoilage of food by hindering micro-organism growth such as bacteria, fungus, molds etc. 3
  4. 4. Why Food Preservation is Important? Food Preservation Increase the shelf life of the product Made available throughout the year Variety in diet and balanced To save food for future (During drought, floods etc.) Preservation techniques tends to reduce cooking time and energy required To stable the price of product throughout the year (Seasonal foods can be preserved and made available throughout the year) Reduces loss/wastage of perishable goods E.g.: Fruits stored at ambient temperature can be edible for 2-3 days but storing in low temperature can make them edible for 10- 14days/more Overall food supply is maintained 4
  5. 5. Principles of Food Preservation • Avoiding invasion of microorganisms E.g. Asepsis techniques • Removing microbes E.g. Filtration methods • Inhibiting the growth & activity of microorganisms E.g. Freezing, Drying, Chemicals etc. • Killing the microorganism E.g. Heat/irradiation Prevention/Delay of the growth of micro-organisms • Destruction/inactivation of inherent enzymes naturally existing in food. E.g. Blanching • Prevention/delay of chemical reactions. E.g. Prevention of oxidation by addition of antioxidants Prevention/Delay Self- • By using suitable chemicals to kill insects or animals from destroying the foods. • By storing foods in dry, air tight containers to prevent the insects or animals from destroying them Prevention of damage from insects and animals 5
  6. 6.  Food preservation techniques combines science-based knowledge with technologies, to prevent spoilage and extend shelf-life and ensure consumers free of pathogenic microorganism food.  Deterioration of food leads to loss of quality including color, texture, taste as well as nutritive value.  Cause of deterioration may be due to physical, chemical or biological, microbial factors.  Preservation methods should be applied as early as possible in production pipeline and therefore include proper postharvest handling before processing of both plant and animal foods 6
  7. 7. Major Food Preservation Techniques Food preservation methods Inhibition Inactivation Avoid Recontamination Low-temperature storage Sterilization Packaging Reduction of water activity Pasteurization Hygienic Processing & Storage Decrease of oxygen Irradiation Aseptic Processing Increase of carbon dioxide Electrifying HACCP Acidification Pressure GMP Fermentation Blanching ISO 9000 Adding preservatives Cooking TQM Adding antioxidants Frying Risk analysis & management Control pH Extrusion Freezing Light Drying Sound Concentration Magnetic Field Surface coating Structural modifications Chemical modifications Gas removal Changes in phase Transition Hurdle technology 7
  8. 8. Methods of Preservation (A) Asepsis It refers to the absence of disease-causing micro-organism. The main aim of asepsis is to prevent contamination which can be done through using sterile devices, materials and instruments & by creating an environment low in microbial volume.  Natural protection – outer layer of animal and plant tissue protects the inner layer free from micro- organism. This protective layer will delay/prevent the microbial decomposition. E.g. Shells of nuts, skin of fruits and vegetables etc.  Packaging of foods – prevents entry of microbes such as in wrapping, hermetically sealing.  In food industries mainly is concerned with prevention of contamination of foods concerning the “bioburden” of microorganism on/or in food. 8
  9. 9. (B) Filtration Filtration is one of the method to remove microorganism from liquids like water, juices, beer etc. Sterilized filter is used to separate the microbes by passing the liquid through the filter by application of pressure. Microorganism get struck and cannot pass through the filter and liquid free of microbes are passed through the filter. (C) Anaerobic Condition Refers to condition with no or minimum air/oxygen that helps to hinder the growth of bacteria. Food is completely filled in container and air in unfilled space is replaced by carbon dioxide or nitrogen. 9
  10. 10. (D) Heat treatment Most common method of preservation to kill the microorganisms. There are types of heat treatment which depends on the kind of microbes and food composition. They are: 1.Pasteurization (temperature below 100℃) – tends to kill part of microbes below 100ºC Temperature ranges from 65ºC-75ºC. There are two ways of pasteurization: ❖ HTST (High temperature-short time) Food product is heated at high temperature for a short time. For example, milk is heated to 72℃ and held for 15 seconds. ❖ LTLT (Low temperature-long time) Food product is heated at a lower temperature for longer period of time. For example, milk is heated to 62.8℃ and held for 30 minutes. 10
  11. 11. 2.Boiling or heating at about 100℃ Most fruits and vegetables can be preserved for a longer time by applying heat at about 100℃. Inherent enzymes which initiate self-decomposition can be destroyed after boiling at 100℃. This process is called blanching. 3.Sterilization(temperature 100ºC or above) It is a process that all micro-organisms are being killed at high temperature or radiation. The time and temperature necessary for sterilisation vary with the type of food. Type of Food Temperature Duration Fruits & Tomato 100℃ 30min Vegetables 116℃ 30-70min Milk (UHT) 135℃ Not less than 1 sec 11
  12. 12. Major difference between pasteurization & sterilization Pasteurization Sterilization Function Partial destruction of microorganism Complete destruction of microorganism Temperature Below 100ºC Above 100ºC Advantage Minimum damage to flavor, texture and nutritional quality Long shelf life No other preservatives method necessary Disadvantage Short shelf life Another preservation method must be used like refrigeration/freezing. Food is overcooked. Major changes in texture, flavor & nutritional quality. 12
  13. 13. 4. Canning It’s a method that sterilizes food by heat in airtight containers to achieve a commercially sterilized product, which allows food to be stored at room temperature while maintaining food safety & organoleptic quality for months/years. (E) Use of low temperature and cold preservation Low temperature helps to slow down the microbial activities. Refrigerated temperature reduces microbial growth rate and chilling temperature inactivates the enzymatic activities. Usual cold storage temperature ranges from 4.5-7ºC and frozen food temperature is below -18ºC (F) Drying or dehydration Drying is one of the old technique used for preservation. It simply means the removal of water from the food which inturn reduces water activity and hence helps in preventing the growth of microbes. Drying is done naturally under sun-drying method for specific time Dehydration is done by artificial application of heat. 13
  14. 14. Dehydration Sun-drying A faster process A slower process Under controlled hygienic condition Under open-air condition with little hygienic condition Not dependent on weather Not possible in cloudy/rainy days Investment on machinery & processing cost is needed. No machinery & processing cost needed. Difference between drying & dehydration 14
  15. 15. (G) Use of preservatives Preservatives serve as antimicrobials which prevent or slow down the growth of molds, yeasts and bacteria. An ideal preservative should meet the following criteria: (i) can inhibit the growth of a wide range of micro-organisms (ii) should be non-toxic to humans (iii) should not be expensive (iv) should not affect the flavor, taste or aroma of the food product (v) should not be inactivated by the food itself (vi) should not promote the development of resistant micro-organisms (vii) should kill rather than inhibit the micro-organisms (H) Use of salt and sugar Sugar binds moisture and thus can preserve food by preventing the growth of microorganisms if a high concentration (65% or above) is used. Products such as jams and jellies are preserved by using sugar. Salt in high concentration (15-20%) can prevent the water from being available for bacterial growth. It slow down the growth rate of bacteria and thus the food ispreserved. Salt can be used in brine (salt water) or applied to food directly. 15
  16. 16. Some common preservatives Preservatives Target Organism(s) Action Examples of Application(s) in food Sulphites Yeasts & bacteria Antioxidant Dehydrated fruits & vegetables, wine, juice, sausages Sodium Nitrate Bacteria Antimicrobial Cured meat Propionic Acid Moulds Antimicrobial Bread, Cakes, Cheese Sorbic Acid Moulds Antimicrobial Cheese, Cakes, Salad dressing, wines Benzoic Acid Yeasts & Moulds Antimicrobial Soft drinks, ketchup, salad dressing 16
  17. 17. (I) Use of acids (vinegar or citric acid) Acids lower the pH and thus inhibit the growth of many micro-organisms. It is more effective against and bacteria than molds. About 20% vinegar (acetic acid) prevents the spoilage of most products like pickles, sauces and chutney. Citric acid, is used in the preservation of certain fruits and vegetables. Products of jams, jellies and squashes may contain citric acid. It can prevent the growth of molds. (J) Irradiation Radiant energies can kill microorganisms without marked increase of temperature as well as marked changes in the nature of food. Gamma rays, x-rays and electromagnetic, ultra-violet radiations are commonly used for food preservation. Irradiation can be used in a wide range of area in food (i) Poultry products and seafood (ii) Fruits (iii) Prevention of sprouting in potatoes and onions (iv) Delaying ripening in fruits (v) Preservation of seafood (vi) Prevention of insect infestation in dry foods and food products 17
  18. 18. Are Preservatives Safe? All preservatives must go through rigorous safety assessment and approval procedures. They are for food use only when they are proved to present no hazard to the health at the level of use proposed. All preservatives must go through rigorous safety assessment and approval procedures. They are permitted for food use only when they are proved to present no hazard to the health at the level of use proposed. Nitrite is mainly used in sausages, ham, bacon and pickled meat to inhibit the growth of Clostridium botulinum. Accidental intake of large amount of nitrite can cause a kind of blood disorder called methaemoglobinaemia. Ingested nitrite, in the presence of protein substances in the stomach, may form N-nitroso compounds, which have been shown to be probable human carcinogen and may increase the risk of stomach cancer. Nitrite also occurs naturally in food like cereals and vegetables. If consumers have balanced diets, exposure to a specific chemical will be lowered and so is the risk. 18
  19. 19. REFERENCES  Food Preservation Technology Strand PDF  Science Direct -  Image - Google 19
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