Canning At Home

1. Canning At Home Rick Sloan FCS Agent

2. What will we learn? Principles of Canning Two Methods of Canning Packing Methods Canning Equipment Processing Time Boiling Water Processing Pressure Canning Processing Home Food Preservation 2

3. Principles of Canning Home Food Preservation 3

4. Canning Basics Food is placed in a canning jar and heated to a temperature that destroys targeted microorganisms. Heat also inactivates enzymes that cause spoilage. Air is driven from the jar during heating. As the jar cools a vacuum seal is formed. Home Food Preservation 4

5. Commercial Sterility All pathogens, spoilage bacteria, molds, and yeast are “killed.” Those that survive are thermophilic bacteria that cause spoilage but not illness. Some produce gases. Some produce bad odors. Home Food Preservation 5

6. Vacuum Seal Holds the lid on the jar. Prevents recontamination of the food. Prevents air from drying out the food. Home Food Preservation 6

7. Two Methods of Canning Home Food Preservation 7

8. Two Methods of Canning Boiling Water Canning Used for high-acid foods Pressure Canning Used for low-acid foods. Can also be used for high-acid foods but might result in a soft texture. Home Food Preservation 8

9. High-Acid Foods (pH < 4.6) All fruits, except for: figs tomatoes, and melons Rhubarb Fermented pickles, such as sauerkraut Acidified foods, such as pickles and tomatoes Home Food Preservation 9

10. Low-acid Foods (pH > 4.6) All vegetables, except for rhubarb Meats Poultry Seafood Soups Mixed canned foods (low-acid + high-acid) Home Food Preservation 10

11. Why Two Methods of Canning? Yeast, molds, and most bacteria are killed at boiling temperatures -- 212ºF at sea level. C. botulinum forms spores that require higher temperatures for destruction in a reasonable period of time -- usually 240ºF or above at sea level. Home Food Preservation 11

12. Clostridium botulinum Clostridium botulinum bacteria are found naturally in soil and water. Seven known types, but only A, B, E and F cause illness in humans. This bacterium can produce heat-resistant spores. Home Food Preservation 12

13. C. botulinum -- Growth To germinate, the spores need the following conditions: anaerobic environment (No Oxygen) low-acid food temperature between 40ºF and120ºF relatively high moisture Home Food Preservation 13

14. C. botulinum -- Growth Optimal conditions might be found in: Home canned foods Smoked fish and sausage Foil-wrapped baked potatoes sitting at room temperature Packaged mushrooms Pot pies and other foods in gravy Home Food Preservation 14

15. Botulinum Toxin The botulinum toxin, one of the deadliest known, causes botulism. 1 mg can kill 655 tons of mice. Food can contain toxin without showing any signs. Antitoxin available, but slow recovery. Permanent nerve damage possible. Home Food Preservation 15

16. Botulism -- Symptoms Symptoms usually appear within 12 to 72 h after eating contaminated food: Digestive upset (in some cases) Blurred, double vision Difficulty swallowing, speaking, and breathing Possible death from suffocation 10-35% mortality rate Home Food Preservation 16

17. Preventing Botulism Spores do not grow in high-acid foods. Spores killed when low-acid foods heated long enough at a specific temperature. Process low-acid foods in a pressure canner, which can reach a temperature of 240ºF. Home Food Preservation 17

18. Preventing Botulism Prepare and process food according to instructions in a tested recipe. Canner gauge must be accurate and properly used. Use only high quality raw ingredients. If toxin is suspected, detoxify food before discarding. The toxin is destroyed by boiling even though the spores are not. Home Food Preservation 18

19. Improperly Canned Foods Never consume improperly canned foods. Throw out – do not feed to animals. Boiling will not always adequately destroy toxin. When cleaning up surfaces contaminated by unsafe canned foods, prepare a 1:5 bleach to water solution. Home Food Preservation 19

20. Packing Methods Home Food Preservation 20

21. Raw Pack For foods that lose shape when cooked. Place raw food directly in jars. Pour boiling hot liquid over the food. Pack firmly, do not crush. Add jars carefully to warm canner to prevent jar breakage from heat shock. Preheat water to 140oF before putting raw-packed foods into boiling water bath. Home Food Preservation 21

22. Hot Pack Preferred method for most foods. Food is cooked in liquid before packing. Cooking liquid is then poured over food in jar. Less floating of food pieces in the jar. Better food color and flavor. Easier to pack, foods more pliable Heat in preparing kills some microorganisms. Preheat water to 180oF before putting into boiling water bath. Home Food Preservation 22

23. Canning Equipment Home Food Preservation 23

24. Pressure Canners Flat rack in bottom Pressure regulator or indicator: Dial or weighted gauge Older models have petcocks Vent pipe for pressurizing Safety valves or overpressure plugs Safety locks when pressurized Rubber gaskets in lid (metal to metal seal) Home Food Preservation 24

25. Replacement Parts Dial gauges, when inaccurate Gaskets (sealing rings) Every 2 years usually Rubber overpressure plugs Every 2 years Vent pipes if clogged Air vent/cover lock from lid Weighted gauges or dead weight if lost Home Food Preservation 25

26. Processing Time Home Food Preservation 26

27. Processing Schedules Definition: Length of time at a specific temperature that a food must be processed. Affected by: pH value of the food Composition of the food - Viscosity - Tightness of pack - Convection vs. conduction transfer of heat - Starches, fats, bones Home Food Preservation 27

28. Affected by: Preparation style of food Initial temperature of food as it is filled into jar Temperature of processing Size of jar Shape of jar Processing Schedules Home Food Preservation 28

29. Significance of Heat Penetration Processing time is affected by whether food heats by convection, conduction, or a combination of both. Heat penetration studies used to scientifically determine safe processing times. The “cold spot” in the food must reach the correct temperature for the correct length of time to destroy target pathogens. Home Food Preservation 29

30. Heat Penetration Follow recipe exactly. The following slows heat penetration: Extra sugar or fat Oversized food pieces Added thickeners Use recommended canners. Heat-up and cool-down times in pressure canners are counted toward sterilizing value of the process. Do not rush them. Home Food Preservation 30

31. Processing Time Each food and preparation style has its own processing time so always use a tested recipe. Time differs with size of jar. Too little = under processing  spoiled or unsafe food Too much = over processing  overcooked Home Food Preservation 31

32. Pressure Increases Temperature Heat food to 240oF to destroy botulinum spores. Cannot achieve this in boiling water. The only safe way to can low-acid foods is with pressure. Temperature of 240ºF or above needed for reasonable processing times 10 psig = 240ºF at sea level 15 psig = 250ºF at sea level Home Food Preservation 32

33. Boiling Water Processing Home Food Preservation 33

34. Boiling Water Bath Have water simmering (180oF) in canner, high enough to cover jars when filled (about six inches for most loads). Hot packed jars = simmering water Raw packed jars = warm to hot water Place jars on rack in canner. Add more hot water if necessary, once jars are in canner. (Never pour hot water directly onto raw-packed jars). Home Food Preservation 34

35. Boiling Water Bath Start counting processing time after water returns to a full boil. Adjust processing time for altitudes over 1,000 feet. Home Food Preservation 35

36. Boiling Water Bath If processing foods for more than 30 minutes, water should be two inches over jars when process begins. If water stops boiling at any time during process, bring the water to a boil and begin the process over. Home Food Preservation 36

37. Pressure Canning Processing Home Food Preservation 37

38. Pressure Processing Have 2 to 3 inches of water simmering or hot in canner. Hot packed jars = simmering water Raw packed jars = warm to hot water Place jars on rack in canner. Put lid on canner with weight off or petcock open. Home Food Preservation 38

39. Pressure Processing Exhaust canner for 10 minutes. Close vent or petcock. Start counting processing times when correct pressure is reached. Adjust pressure for altitude, if needed. Turn off heat at end of processing. Let pressure drop to 0 psig naturally. Home Food Preservation 39

40. Pressure Processing Wait two minutes after pressure drops to 0 psig. (For some canners, check that locks in handles are released.) Remove weight or petcock. Open canner. Watch steam! Remove jars to padded surface or rack. Cool jars 2 to 24 hours, undisturbed. Check that the jars have sealed. Home Food Preservation 40

41. MODULE 3Canning High-Acid Foods Home Food Preservation 41

42. MODULE 3: Units Definition of a High-Acid Food Preparing Foods for Canning Acidifying Tomatoes Canning High-Acid Foods Home Food Preservation 42

43. Definition of a High-Acid Food Home Food Preservation 43

44. High-Acid Foods (pH < 4.6) All fruits, except for: figs tomatoes, and melons Rhubarb Fermented pickles, such as sauerkraut Acidified foods, such as pickles and tomatoes Home Food Preservation 44

45. Preparing Foods for Canning Home Food Preservation 45

46. Selecting Fruits and Tomatoes for Canning Choose firm, ripe products. Do not use overripe fruits. Gather or purchase only what you are able to can within 2 to 3 hours. Home Food Preservation 46

47. Washing Fruits and Tomatoes for Canning Dirt contains many microorganisms hardest to kill. Wash everything, even foods to be peeled. Use several water changes. Lift the food, do not soak. Home Food Preservation 47

48. Preventing Fruit Darkening 1 teaspoon (3000 mg) ascorbic acid added to one gallon of water Commercial ascorbic acid mixture Heating the fruit Home Food Preservation 48

49. Preventing Fruit Darkening The following do not work as well: Citric acid solution Lemon juice Sugar syrup Salt/vinegar solution Home Food Preservation 49

50. Canning Liquids for Fruits Sweet syrup, water or juice can be used. Sweet syrup: Helps retain shape, color, and flavor of fruit. Not needed for safety Mix sugar with water or juice, heat to dissolve sugar. Proportions of sugar to liquid given in publications. Up to 1/2 the sugar can be replaced by corn syrup or mild flavored honey. (Use more corn syrup if bland.) Home Food Preservation 50