The document discusses various methods for preserving meat, including freezing, cooking, drying, chemical preservation, fermentation, irradiation, canning, vacuum packing, and curing. It explains how each method works to inhibit bacterial growth and spoilage by removing water, raising or lowering the temperature, changing the pH, or using other techniques to make the environment inhospitable for microorganisms. The key factors in meat preservation are controlling temperature, moisture level, pH, and atmospheric conditions.

1. Meat Preservation

2. Meat Putrefication Meat is putrefied due to the action of bacteria , moulds , yeasts. To grow and proliferate the organisms temperature is necessary. Due to this classify the organisms, 1-Pschyrophiles: have optimum temperature range of -2 to 7*c. 2-Mesophiles: have 10 to 40*c. 3-Thermophiles: have 43 to 66*c . Organisms also need water for growth.

3. Why Preserve Meat??? Delays product spoilage Extends life of the product Improves product quality

4. Preserve Meat To preserve the meat temperature must be 1- : -2*c by chilling or freezing. 2- : 66*c by pasteurization , cooking or sterilization. To preserve the meat , remove the water by dehydration , freezing , curing.

5. Types of Preservation Techniques Freezing Cooking Dehydration Chemical Fermentation Irradiation

6. Types of Meat Preservation Drying- Removal of water from meat. Heating- Kills bacteria if temperatures reaches 160 degrees. Refrigeration- Slows the growth of bacteria Freezing- 20 degrees below zero eliminates bacterial growth Acidification- Low pH retards bacterial growth

7. Types of Meat Preservation 6. Irradiation - Low levels kill bacteria in fresh meat products Canning- Packaging meat into sealed containers and heating meat to kill bacteria Curing- Compounds make meats inhospitable to microbial growth. Salting and Sugaring- Prevents microbial growth Smoking- Forms antibacterial chemicals to the meats surface

8. Typical Methods of Food Preservation : High temperature Pasteurization kills spoilage and pathogenic organisms (1864 – Pasteur) Longer temperatures and times can sterilize foods Low temperature Refrigeration or freezing inhibits microbial growth

9. Typical Methods of Food Preservation : Dehydration Air drying Chemical preservatives Inhibitors of organism growth such as salt, sodium nitrite, and propionates Bactofugation Removing bacteria from liquids by centrifugation

10. Freezing Optimum temperature (0 °F or lower) Meat freeze at -1.4*C Works by completely stopping enzyme activity & inhibiting spoilage microorganisms Bacteria Yeasts Molds

11. Freezing REMEMBER: Thaw meat at refrigeration temps or in the microwave DO NOT THAW AT ROOM TEMPS

12. How long with frozen meat last? Beef – 12 months Pork - 6 months Lamb – 6-9 months Poultry – 3-6 months

13. Disadvantages of freezing Frozen meat stored too long become dry , less palatable and rancid. After thawing it is less durable than fresh-killed or chilled meat. When frozen meat is thawed it weeps or drips which consist mainly of water, salt, protein and demaged blood corpuscles. Loss of weight due to drip in beef is up to 3% while in mutton , lamb or pork loss is less than beef.

14. FREEZER BURN Yellowish –brown or whitish areas seen on the surface of frozen meats. It is due to excessive drying of the surface. Phenomenon involves the formation of a condensed layer of the muscular tissue just under the surface. this prevents moisture coming to the surface from the depth of the meat.

15. Chilling of meat It is useful when meat is stored for short time up to 35 days. It is kept at b/w -1.4*c and 1*c preferably in the dark as light has the effect of oxidizing fats. Atmosphere keep dry to prevent the mould formation 5-10%CO2 helps to prevent the growth of mould and bacteria. It is important that temperature does not reach -1.4*c otherwise meat is frozen..

16. Cold shortening Toughness develops in lamb carcasses, if they are exposed to low temperature within about 16 hours after slaughtering pH is about 6.3 and ATP levels are high ,lowering of the temperature causes the muscle to contract. It starts normally at 15*c and become greater down to 0*c. Beef carcass do not chilled quickly b/c of the thickness of the muscles. Due to rapid fall in the pH there is no problem of cold shortening in the pig carcass.

17. Cooking Works by heating products to high temperatures to kill microorganisms 2 types of cooking Pasteurization Sterilization

18. Pasteurized Cooking Products are cooked to 150-170 °F Kills most (but not all) microorganisms Product must be REFRIGERATED Example: “Hotdogs”

19. Sterilized Cooking Products cooked under pressure to 250 °F All microorganisms killed Products are shelf stable Example: Canned Hams

20. Smoking - Meat, fish and some other foods may be both preserved and flavored through the use of smoke, typically in a smoke house . The combination of heat to dry the food without cooking it, and the addition of the aromatic (phenolic)hydrocarbons from the smoke preserves the food.

21. Vacuum packing Vacuum-packing stores food in a vacuum environment, usually in an air-tight bag or bottle. The vacuum environment strips bacteria of oxygen needed for survival, slowing spoiling.

22. Canning Canning : food is sealed in a container such as a can or glass jar and heated to kill all living organisms, or at least to ensure that there will be no growth of residual organisms. Acidic foods should be heated to 100 °C, whereas nonacidic foods should be heated to 121°C. Properly canned foods may not be sterile b/c heating them for the time required might alter the foods’ taste and nutritional value. Since some of the anaerobic organisms that can grow in cans are from the genus Clostridium , food from a can that is visibly altered, ex. bulged can, should not be eaten .

23. Dehydration Oldest forms of preserving meat Works by removing water from the product water is required by all microorganisms to grow NO WATER = NO GROWTH

24. Dehydration Dehydrate by air drying, heating, or freezing Example: “Beef Jerky”

25. Chemical Chemicals inhibit microorganism growth Salting or curing draws moisture from the meat through a process of osmosis. Examples Salt Sodium Nitrite Sodium Lactate

26. Chemical Preservatives Sodium Benzoate Sorbate Proprionates

27. Chemical Preservatives Sulfur Dioxide Nitrates and Nitrites BHA/BHT

28. Chemical Other benefits: Add flavor to the product Improve product shelf life Develop a pink cured-meat color All Chemicals added to meat are FDA approved

29. Fermentation Works by changing sugar into acid Acid prevents microorganisms from growing Tangy flavor and special texture developed Example: “Pepperoni”

30. Modified Atmosphere Preservation MAP – Modified Atmosphere Packaging Carbon Dioxide Types Hypobaric Vacuum Packaging MAP Equilibrium Modified Atmosphere Controlled Atmosphere Packaging

31. MAP Equipment

32. Irradiation A new process to make food SAFER!!!! Works by exposing meat to radiant energy Destroys most (but not all) microorganisms “ Radura” sign on labels

33. Irradiation Reduces spoilage Irradiated meat is still nutritious Irradiated meat needs to be COOKED IRRADIATED MEAT IS SAFE TO EAT!!!!

34. Irradiation unit

35. The 5 Factors in the Curing Process Flavor Color Tenderness Preservation Yield

36. Preservation 3 main ingredients to preservation process Salt Sugar Nitrite

37. Flavor Flavor is the primary reason consumers purchase meat more than once Salt- Predominant flavor in most processed meats Sugar- Used to reduce the harshness of the salt flavor Nitrite- Provide a characteristic flavor you recognize as a ham flavor Smoked- Contains a smoke flavoring rather than being traditionally smoked

38. Color and Tenderness Color- If nitrate is used the meat will take on a distinctive red color. Tenderness- The type of process will affect the tenderness of the meat. Examples: Jerky the meat is dry and tough Ham usually fairly tender

39. Yield When meat products are cooked and smoked, some water and juices are lost, making the product weigh less, thus reducing the product’s value. Moisture- Helps prevent moisture loss during cooking and smoking Increased Profits- Adds weight to products increasing the price of the product. Curing- Used to deliver cure ingredients into the fresh meat prior to curing.

40. The Curing Process Non-Meat Ingredients Not meat!!! Ingredients Increase product yield Aid in color, texture or flavor development Increase product shelf-life Increase process efficiency

41. Questions Please contact Dr. Elizabeth Boyle or Ryan Timm at (785)532-1247 email: [email_address] [email_address] Please contact Dr.M.Arshad.Javid email: [email_address] OR Call your county extension office