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Food Deterioration and its Control1.pptx
- 1. Emerson university Multan Department of English Session 2022-2026 Topic Food deterioration and its control
- 2. Presented to Ma’am Izna Tariq Presented by Group D Tayyaba iqbal Okasha zameer Alishba batool Sheeza hassan Aliya shabir Anam shahzadi Alishba azam
- 3. Food Deterioration And Its Control Food deterioration is a process that renders a product unacceptable or undesirable for consumption and is the result of the biochemical activity of microbial papulations that predominate in the product .
- 4. • ReasonForDeterioration • Biological • Chemical • Physical • Biological – Theunwantedmicrobesdecompose thefood andmakethemunfit forconsumptionofbacteria • Chemical – Enzymaticor anyother chemicalreactions cancausechsngesin food structureandmakeitunfitfor intake
- 5. • Physical Exposure of food to some external factor like air moisture or temperature changes can cause food spoilage.
- 6. • Microbial Activity • Microorganisms natuurallyoccurintheenvirnmentand theycancausefoodtobecomerotten • Therearethreetypesoforganisms are • Bacteria • Yeast • Moulds Bacteria.A microscopicoganismsthatcausefood poisoning whenconsumedBacterialikemostwormlow acidenvirnment
- 7. • Yeast.They are single-celled plant organisms that can produce Slime on fruit juices and vinegar. • Moulds.They are different from other micro-organisms as it can be seen naked eye
- 8. • All food undergo deterioration after harvest to some degree • Role of food sciences is to minimize the negative changes to the extent
- 9. Deterioration includes changes in • Organoleptic quality • Nutritional value • Food safety • Aesthetic appeal • Color • Texture • Flavor • Etc.
- 10. • Factor causing detrioration • Cold • Light • Other radiation • Heat • Oxygen Moisture • Dryness • Enzyme • Texture • Micro-organisms • Food safety • Asthetic appeal
- 11. • Useful Life (In days) at 21oC • Shelf Life • Time required for a food product to reach unacceptable quality • Depends on • food item • processing method • packaging • storage conditions
- 12. Food Dating • Types of Code Dates • Date of manufacture (pack date) • Date of display (display date) • Last date to sell (sell by date) • Last date of minimum quality (best used by date) • No longer acceptable date (expiration date)
- 13. • Envirnmental condition affecting microbial growth • Temperature • psychrophilic lt16oC • mesophilic 16-38oC • thermophilic gt38oC • Oxygen • Aerobic (some bacteria, all molds) • Anaerobic (some bacteria, yeast) • Facultative (both with and without oxygen) • Obligative (either with or without oxygen)
- 14. • Food borne disease • Food infection • Microorganism must be present in the food and will set up infection in humans • Food intoxication • Food contains a chemical which is toxic to humans
- 15. Food intoxication • Staphylococcus aureus and Clostridium botulinum produce toxins • Molds produce mycotoxins (ex aflatoxin) • Toxins often are not destroyed by heat (cooking)
- 16. Food infection • Clostridium perfringens, Salmonella sp., and several others including Escherichia coli (strain 0157H7)
- 17. Insect parasites • Damage 5-10 of the US grain crop • Insects can cause minor damage, but wound tissue allowing for further microbial damage • Control • Pesticides • Inert atmospheres • Cold storage
- 18. Insects Parasites • Damage 5-10 of the US grain crop • Insects can cause minor damage, but wound tissue allowing for further microbial damage • Control • Pesticides • Inert atmospheres • Cold storage
- 19. • Acceptable Levels of Fly Eggs Larvae in Tomato Products
- 20. Enzymatic Changes Enzymes help to speed up reactions Some enzymes found naturally in food and cause food spoilage This process does not switch itself and continues it to sit in a fruit bowl for a while it will begin to brown and soft
- 21. Food Enzymes • All foods from living tissues contain enzymes • Most of these enzymes willsurvive harvest and/or slaughter • At the time of harvest or slaughter, enzymes which control digestion/respiration proceed uncontrolled and cause tissue damage
- 22. Controlling Enzymes • Inactivation by heat • Chemicals • Radiation • Some post-harvest enzymatic reactions are desirable (i.e. ripening of tomatoes, aging/tenderizing of beef)
- 23. Heat Cold • Normal harvest temperatures range from 10- 38oC • The higher the temperature, the faster the biochemical reactions • Rate of chemical reactions double with each 10oC rise in temperature • Sub-freezing temperatures damage tissues
- 24. Examples of Cold Damage • Discoloration of tissues when frozen • Changes in texture when frozen • Milk emulsion will be broken • Milk protein will denature and curdle • Chill injury can occur near freezing, esp. in tropical fruit tissues (ex banana)
- 25. • Envirnmental Factors Food can be contaminated as a result of envirnmental factors In contact with dirt and dust Insect spray being used in kitchen when food is uncovered . Food being exposed in air. Damaged packaging A food handler using a gloved hand for both serving and handling money.
- 26. Oxygen • Chemical oxidation reactions can • destroy vitamins (esp. A C) • alter food colors • cause off-flavors • promote growth of molds
- 27. Principles for food preservation • Heat • most bacteria are killed at 82-93oC, but spores are not • 121oC wet heat for 15 minutes is required to ensure sterility • high acid foods require less heat • in milk, only disease-causing organisms are killed to reduce the severity of heat required
- 28. • Drying • microorganisms contain approx. 80 moisture • dehydrating food also dehydrates the microorganisms
- 29. • Acidification • acids may be in foods naturally, produced by fermentation, or added artificially • as pH decreases, heat required for sterilization is reduced
- 30. Time Required to Destroy C. botulinum Spores
- 31. Sugar salt Addition of either to a food item increases the affinity of the food for water, thereby removing water from the microorganism through osmosis
- 32. Smoke • Contains formaldehyde and other preservatives • Heat will help reduce microbial populations and somewhat dries the food •
- 33. Atmosphere • Exclude air (O2) for control of aerobes • Provide air (O2) for control of anaerobes • Add CO2 • Add N2
- 34. Chemical • Sodium benzoate • Sorbic acid • Sodium or calcium propionate • Sulfur dioxide
- 35. Radiation • X-Rays • Microwaves • Ultraviolet light • Gamma Rays • etc.
- 36. Common Method For Preservation Of Food Chilling and freezing Canning Dehydration Fermentation Salting Sweetening Vaccum Packing Pastuerization Fermentation.
- 37. Thank You