Department of Food Science & Technology Department of Food Science & Technology Hands-on Canning Experience July 1, 2015

Department of Food Science & Technology Department of Food Science & Technology Why Preserve Foods? Prevent Spoilage of Foods & Extend Shelf Life Types of Spoilage: –Microbiological Molds, yeast, bacteria –Chemical Enzymatic changes –Physical Bruising, water loss

Department of Food Science & Technology Department of Food Science & Technology Special Pathogen to consider when canning: Clostridium botulinum Spore-former: spores ubiquitous in the environment –Spores can’t make you sick –Infant botulism ONLY: Under conditions w/ NO OXYGEN (commonly created during preservation), spores germinated into vegetative cells Vegetative cells produce toxin

Department of Food Science & Technology Department of Food Science & Technology Botulism: Ingestion of toxin in foods Neurotoxin Causes paralysis and death if medical attention isn’t found quickly Very rare in U.S. now Primarily associated w/ improperly home canned

Department of Food Science & Technology Department of Food Science & Technology Boiling Water Bath Canning

Department of Food Science & Technology Department of Food Science & Technology Boiling water bath canning: Large covered cooking pot with a rack Must be deep enough to cover 1 inch above jars Processes foods at boiling temp. (212°F) Acid / acidified foods Heat destroys m/o that spoil acid foods

Department of Food Science & Technology Department of Food Science & Technology Important notes: Fruit Some recipes call for ascorbic acid dip –Apples, pears, nectarines, apricots, peaches etc…. –Pure powdered form –Vitamin C tablets –Commercially prepared mixes This dip prevents the fruit from browning while preparing jars

Department of Food Science & Technology Department of Food Science & Technology Important notes: Pickling Pickled foods are acidified, therefore they can be heat processed in a boiling water bath –Prevents spoilage organisms and inactive enzymes Fermentation –Dill pickles/saurkraut – 3 weeks –Refrigerated dill pickles – 1 weeks –Quick process – not fermented

Department of Food Science & Technology Department of Food Science & Technology Important notes: Pickling Level of acidity should not be altered –Recipe MUST be followed Use canning/pickling salt –Other salt has non-caking material added which can make brine cloudy

Department of Food Science & Technology Department of Food Science & Technology Important notes: Jams and Jellies Ingredients –Fruit, pectin, acid, and sugar Pectin –Form a gel when in the right combination of acid and sugar –All fruits contain some pectin –Fully ripened fruit has less pectin (when not adding pectin, ¼ fruit should be under-ripe)

Department of Food Science & Technology Department of Food Science & Technology Important notes: Jams and Jellies Acidity –Too much – gel won’t set –Too little – gel with lose liquid –Low acid fruits must have lemon juice added –Commercial pectins contain acid to help w/ gelling Reduced sugar –Must be made w/ low-methoxy pectin (requires addition of calcium to gel) –Typically need to be processed longer

Department of Food Science & Technology Department of Food Science & Technology Pressure Canning

Department of Food Science & Technology Department of Food Science & Technology Pressure Canning: Heavy pot, lid can be sealed: fitted w/ vent and pressure dial or weighted gauge Processes foods at 240°F (10-11 pds pressure) ONLY safe way to process low acid foods

Department of Food Science & Technology Department of Food Science & Technology Weighted –vs- Dial gauge: Weighted gauges: ft: 10 lbs pressure Over 1000ft: must be operated at 15 lbs pressure Dial Gauges: ft: 11 lbs pressure Over 2000ft: corrections must be made Ex: –2001ft-4000: 12 lbs –4001 – 6000: 13 lbs

Department of Food Science & Technology Department of Food Science & Technology Ensuring Quality: Use only high quality foods, free of bruises and blemishes Can/preserve w/in 6-12 hours of harvest Hot pack (especially acid foods) –Helps to remove air from the food –Keeps food from floating in jar –Increases the vacuum seal –Helps food maintain color during storage

Department of Food Science & Technology Department of Food Science & Technology Importance of headspace: Jams/jellies: ¼ inch Fruits / tomatoes: (boiling water bath): ½ inch Low acid: 1-1 ¼ inch Needed for expansion of the food –Higher the temperature, the greater the expansion Forming vacuum in cooling jars

Department of Food Science & Technology Department of Food Science & Technology Appropriate Jars/Lids & Closing