General principle methods of preservation

Food Microbiology

1. VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMEN Veerechipalayam – 637 303, S ankagiri, Salem Dt., Tamilnadu India. Affiliated to Periyar University, Salem ; Recognised Under Section 2(f) & 12(B) of the UGC Act, 1956) DEPARTMENT OF MICROBIOLOGY SUBJECT: FOOD MICROBIOLOGY SUBJECT INCHARGE: SUBMITTED BY: Dr. R. DINESHKUMAR, SASIPRABHA THANGAVELU, Assistant professor, III B.Sc., Microbiology, Department of Microbiology Department of Microbiology, VIAAS, Sankagiri. VIAAS, Sankagiri. TITLE : GENERAL PRINCIPLE METHODS OF PRESERVaTION

2. FOOD PRESERVATION

3. OVERVIEW: What is food preservation Methods of food preservation 1.Control of water activity 2.Control of Microbial growth 3.Control of oxygen level 4 . Use of chemical preservatives 5 . Use of biological agents 6 . Physical methods Different methods of preservation 1. Fermentation 2. Dehydration 3. High temperature 4. Low temperature 5. Irradiation

4. What is Food Preservation ? Food preservation is the process of treating and handling food to prevent spoilage and foodborne illness, while maintaining its nutritional value, texture, and flavour. It involves applying science-based knowledge through various technologies and procedures to extend the shelf life of food products.

5. METHODS OF FOOD PRESERVATION 1 . Control of water activity 2. Control of Microbial growth 3. Control of oxygen levels 4. Use of chemical preservatives 5. Use of biological agents 6. Physical methods

6. METHODS OF FOOD PRESERVATION : Food preservation involves various techniques to prevent spoilage, maintain nutritional value, and ensure food safety. The general principle methods of food preservation can be categorized into several groups, 1. Control of water activity: Dehydration: Removing water from food to inhibit microbial growth Concentration: Increasing the solid content of food to reduce water activity Humectants: Using substances like sugar or salt to bind water and reduce availability

7. 2.Control of Microbial growth: Heat processing: Using high temperature to kill microorganisms (e.g., pasteurization, sterilization ) Refrigerator: Slowing down microbial growth through low temperatures Freezing: Stopping microbial growth through extremely low temperatures 3. Control of oxygen levels: Vacuum packaging: Removing air to prevent microbial growth Modified atmosphere packaging: Replacing air with gases like nitrogen or carbon dioxide Aseptic packaging: Filling containers in a sterile environment to prevent contamination

8. 4. Use of chemical preservatives: Acidulants: Adding acids like citric or lactic acid to create an unfavourable environment Antimicrobials: Using substances like sodium benzoate or potassium sorbate to inhibit growth Antioxidants: Preventing oxidation reactions that can lead to spoilage 5. Use of biological agents: Fermentation: Using ionizing to kill microorganisms to preserve food (e.g., yogurt, sauerkraut) Probiotics: Adding beneficial microorganisms to promote gut health

9. 6. Physical methods: Radiation: Using ionizing radiation to kill microorganisms High-pressure processing: Using intense pressure to inactivate microorganisms Pulsed electric fields: Using high-voltage pulses to inactivate microorganisms These principle methods are used in various combinations to achieve effective food preservations. Understanding these principle is curcial for developing effective food preservations techniques and ensuring the safety and quality of food products.

10. Some of the key factors that influence food preservations include: Water activity pH levels Temperature Oxygen levels Nutrient availability By controlling these factors, food preservation methods can effectively prevent spoilage, maintain nutritional value, and ensure food safety.

11. DIFFERENT METHODS OF FOOD PRESERVSTION 1 . Fermentation 2. Dehydration 3. High temperature 4. Low temperature 5. Irradiation

12. DIFFERENT METHODS OF PRESERVATION: FERMENTATION: Fermentation is a food preservation method that involves the action of microorganisms, such as bacteria or yeast, to break down the sugars in food and create lactic acid or alcohol. This process creates an environment that is not favourable for the growth of pathogens and spoilage microorganism, allowing the food to be stored for longer periods.

13. DEHYDRATION: Dehydration is a food preservation method that involves removing the water content from to prevent the growth of microorganisms, yeast and mold. Methods: Air drying, Sun drying, Smoking, Freeze-drying, Spray drying, Vacuum drying. Example: Dried fruits, Jerky, Cured meats, Instant coffee, Powdered milk.

14. HIGH TEMPERATURE: High-temperature also known as heat processing or thermal processing, is a method of preserving food by using temperatures to kill off microorganisms, extend shelf life, and maintain nutritional value. Methods: 1.Pasteurization 2.Sterilization 3.Canning 4.Retorting 5.Heat temperature Example: Vegetables, Meat, Soups, Milk, Eggs, Seeds, Dried fruits

15. LOW TEMPERATURE: Low temperature can be defines as removing heat energy from the foods, which consequently decreases the temperature or can change the state from water to ice. Methods: 1. Refrigeration 2. Chilling 3. Freezing 4. Ice packing Examples: Meat, Fish, Fresh milk, Butter, Cheese, Jams, Juice, Vegetables.

16. I RRADIATION: Food irradiation is a process that exposure food to ionizing radiation to kill microorganisms, extend shelf life, and reduce the risk of foodborne illness. Methods: 1. Gamma radiation 2. X-ray radiation 3. Electron beam radiation Examples: Leafy greens, Broccoli, Garlic powder, Wheat, Shrimp, Blueberries, Rice.

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