1. Just Can It! Food Preservation Basics
Debbie Clouthier
Extension Associate
February 2015
Images from 123RF.com

2. The Basics Food safety and sanitation Bacteria and how they grow
Research-based home canning techniques
principles of home canning
ingredients
recipes
equipment
high- and low-acid foods
using a boiling water bath canner (Lunch!)
using a pressure canner
food spoilage
What’s new?
Drying foods at home
Home freezing basics
Where to go for research-based answers

3. Food Safety and Sanitation

4. Food Safety & Sanitation
PUT FOOD SAFETY FIRST!
Growers should use fertilizers and pesticides correctly—read the label!
Growers should reduce the risks of potential contamination
minimize exposure to animal waste
use potable water for irrigation
do not use fields for dumping trash
Food handlers should practice good personal hygiene
Food safety starts on the farm or in the garden.

5. The Safe Food Handler Keep yourself neat, clean and healthy
Most important to prevent the contamination of food products:
HAND WASHING!
Also:
Keep yourself neat, clean and healthy
Protect food from open cuts or sores
Avoid smoking, eating or drinking
Keep all equipment and surfaces clean
Wash hands with warm water and soap for at least 20 seconds before and after handling food, and after using the bathroom, changing diapers and handling pets.

6. The Sanitary Kitchen Washed, rinsed and sanitized
Clean means free of visible soil
Wash cutting boards, utensils and counters with hot, soapy water
Sanitary means free of harmful levels of disease-causing bacteria
Sanitize with hot water or chemical sanitizer/bleach
Sanitizing occurs with hot temperature of 179 degrees for 30 seconds or a chemical bath for 1 minute.
Bleach: 1 tablespoon per gallon of warm (not hot) water, scant 1 teaspoon per quart of water, or ¼ teaspoon per cup of water.
Bleach solution should be made fresh daily (loses strength over time).

7. BACTERIA ~ HOW THEY GROW
Food spoilage can be caused by bacteria, yeasts, molds and enzymes that are present in foods and in the environment.
From a food safety point of view, bacteria are of chief concern.

8. Requirements for Bacteria to Grow
Food
Acidity (pH)
Time
Temperature
Oxygen
Moisture (Aw = water activity)

9. Food Food for us = Food for bacteria
Images from Microsoft Office Clip Art

10. Acidity: pH of Common Foods
Tomatoes
Cucumbers
String beans 5.6
Beets
Cabbage
Corn
Grapes 2.8 – 3.8
Strawberries 3.0 – 3.9
Apples 3.3 – 4.0 Peaches 3.3 – 4.0
Acid level is measured by pH (scale 0 – 14).
Low pH = high acidity (fruits).
High pH = low acidity (vegetables, meats).
In bacterial growth/food preservation, the cutoff between high and low acid is pH 4.6.
C. botulinum will not grow and produce toxin at pH below 4.8.
Bacteria will not grow well at pH below 4.6
High Acid Foods
Low Acid Foods
4.6

11. Time: Bacterial Reproduction
Given the right conditions, bacteria reproduce by enlarging and then dividing in two. The two bacteria than each divide into two more cells, and so on. The result of this kind of growth is a tremendous increase in the numbers of bacteria over a relatively short period of time.
It takes 1 million Salmonella bacteria to make a person ill. So under favorable conditions, 10 Salmonella on a product can reproduce to numbers that could make you ill in less than 3 hours. Colonies can be in the billions within hours and may actually be visible to the naked eye.
The result of this kind of growth is a tremendous increase in the numbers of bacteria over a relatively short period of time.
Compliments of National Restaurant Associations of National Restaurant Association
Compliments of National Restaurant Association

12. Temperature Requirements
Psychotrophic
Grow best at 58 – 68 °F
Can grow slowly at refrigerator temperatures
Mesophilic
Grow best at 86 – 98 °F
Most of the microorganisms that affect food safety grow within this range
Clostridium botulinum of special concern
Thermophilic
Grow best at 122 – 150 °F
Spoilage bacteria—most affect food quality, not food safety
For each type of bacteria, there is an optimum temperature range for growth.
Images from 123RF.com

13. Temperature: Food Danger Zone
Bacteria survive and grow
40ºF - 140ºF
Bacteria Reproduce Rapidly
Keep cold foods cold!
Keep hot foods hot!
Perishable foods should be stored at 40F or lower.
Hot foods should be kept at 140F or higher.
60°F
40°F

14. Oxygen Requirements Aerobic Anaerobic Facultative with oxygen
out in the air
Anaerobic
without oxygen
canned foods
Clostridium botulinum
Facultative
either with or without oxygen
cause most foodborne illness
Anaerobic – also vacuum-sealed pouch, large pot of food.
Images from 123RF.com

15. Moisture Requirements
Water Activity (Aw) = measure of water available for bacterial growth
Minimum required
for bacteria to grow
PHF
0.67
0.75
0.98
0.5
1.0
0.92
0.95
Soft
cheese
Dry egg noodles
Bacteria need water to grow. Minimum Aw for bacterial growth is 0.85.
PHF potentially hazardous foods Aw>0.85.
If water molecules are attached to other substances (e.g. sugar or salt) or frozen solid, they are not available for bacteria to use.
Minimum Aw for C. botulinum growth 0.93.
0.85
Meats
Poultry
Most fresh and canned fruits, vegetables, meat and fish have Aw > 0.95
Flour
Candy
Jams
Jellies
Crisp cooked bacon
Raw bacon
Distilled water

16. Requirements for Bacteria to Grow
Food
Acidity (pH)
Time
Temperature
Oxygen
Moisture (Aw = water activity)

17. Bacteria Vegetative Cells With Spores Able to grow and reproduce
Some bacteria can exist in 2 forms—in vegetative form or as spores.
Vegetative bacterial cells can grow, reproduce and produce toxin.
Some bacteria form spores to protect themselves from unfavorable conditions in the environment (such as heat, cold, chemicals). Spores can germinate and begin to grow when conditions become favorable again.
Images from Microbiology of Home Canned Foods for Homebased Microprocessors, UK Cooperative Extension.
Spore: a thick-walled formation within the bacterial cell
Does not reproduce
Resistant to heat, cold and chemicals
Can become a vegetative cell when conditions become favorable
Clostridium botulinum
Able to grow and reproduce
May be killed by high temperatures
May survive freezing

18. Clostridium botulinum
Bacterium of chief concern in home canning—produces the toxin that causes botulism
Spores are found in soil and on surface of fruits and vegetables; oxygen in the air prevents them from growing
Spores will not germinate and grow (producing botulism toxin) until conditions are favorable:
low oxygen (as in canned foods)
low acidity (pH > 4.6)
Cannot grow in high acid foods (pH  4.6)
Spores can survive boiling water bath processing
Image from 123RF.com

19. HOME CANNING BASICS

20. Principles of Home Canning
Select fresh, good quality ingredients
Wash hands, produce, equipment and work surfaces as needed
Use good sanitation procedures
Use research-based recipes
Use appropriate equipment and supplies
Apply enough heat to:
destroy harmful bacteria and spoilage microorganisms
inactivate enzymes
drive air from jars, to produce vacuum seal on cooling
For best quality, preserve foods within 6-12 hours of harvest.
Use research-based recipes for canning all foods, low- or high-acid.
Image from 123RF.com

21. Ingredients Produce start with fresh, top-quality produce
choose varieties best suited for canning
wash produce well
can as soon as possible after harvesting
Canning will not improve the quality of poor-quality produce.
For best quality, preserve foods within 6-12 hours of harvest.
Dirt contains some of the bacteria that are hardest to kill (e.g. spores of Clostridium botulinum)
Image from 123RF.com

22. Ingredients Salt Sugar
adds flavor to canned fruits, vegetables and meats; can be reduced or omitted in these products
needed for safety in fermented pickles and sauerkraut; should not be reduced
pickling or canning salt is the best choice
table salt may cause cloudiness
iodized salt may darken pickles and cause unusual colors in vegetables
Sugar
acts as a sweetener; usually not needed for safety
can be reduced in many recipes
can have a preservative effect
Salt—not a preservative in most canned foods.
Sugar—helps canned fruit maintain shape, color and flavor; preservative effect in jams and jellies, some sweet pickles (ties up water molecules).

23. Ingredients Vinegar Lemon juice Spices
increases acidity; acts as a preservative
adds tart flavor
use commercial (5% acidity) vinegar only
never reduce or dilute in a recipe; add sugar if a less sour product is desired
use white distilled vinegar for light color
Lemon juice
adds flavor
Spices
add flavor

24. Home Canning Recipes Always use current, research-based recipes
Avoid the advice of untrained celebrities, old cookbooks, “back to nature” publications, and out-of-date home canning leaflets (even those from Extension!)
Follow recipes closely; modify only when suggested in the recipe

25. Home Canning Recipes Sources for research-based recipes:
USDA Complete Guide to Home Canning
So Easy to Preserve (University of Georgia)
National Center for Home Food Preservation website
Ball Blue Book Guide to Preserving
UK Cooperative Extension home canning publications—new!
USDA Guide is available for free download from the NCHFP website.
So Easy to Preserve is available from the University of Georgia for $18, including shipping. New edition (6th) released late in 2014.
Ball Blue Book is available from a variety of sources for $ We purchase from the Fresh Preserving Store for $6.49 plus shipping.
New version of Ball Blue Book has just been released; 200 pages (vs 128 pages for earlier version); $11.95 plus shipping.
UK publications: Basics, Jams & Jellies, Tomatoes & Tomato Products, Salsa, Fruits, and Vegetables out in 2014; Meats, Soups & Stews, and Altitude Adjustments in process (Feb. 2015)

26. Headspace
The amount of space from the top of the food or liquid to the top of the jar
Allows the food to expand as the jar is heated during processing, and a vacuum seal to form as the jar is cooled
Different foods require a different amount of headspace
Follow recipe for correct headspace, usually:
¼ inch for jams, jellies and juices
½ inch for fruits, tomatoes and pickles
1 to 1¼ inches for low acid, pressure-canned foods
Show headspace tool.
Image from Microsoft Office clip Art

27. Methods of Pack Raw Pack Hot Pack
raw, unheated food is put directly into jars
boiling hot water, juice or syrup is poured over the food to obtain proper headspace
Hot Pack
food is preheated or cooked for a specified length of time
hot food and liquid are packed into jars
Always use the type of pack specified in the recipe
Hot pack generally yields better color and flavor, especially in a boiling water canner
Hot pack drives air out of food, softens food for easier packing.
Both packs should use enough liquid to fill in spaces and cover the solid food in the jar. If not covered by liquid, food at the top tends to darken and develop unnatural flavors.

28. Jars and Lids
Use only Mason-type jars designed for canning; can be reused; inspect each year for cracks and nicks
Do not reuse commercial single-use jars (e.g. mayonnaise, peanut butter)
USDA recommends two-piece screw-on caps (lids and screw bands)
Lids are used only once; check new lids for dents or uneven sealing compound
Screw bands (rings) may be reused if not rusty or damaged
Jars come in a variety of sizes, from 4-ounce to half-gallon, wide- and regular-mouth.
Half-gallon jars recommended only for very acidic juices.
Scale or hard-water films on previously used jars can be removed by soaking jars for several hours in a solution containing 1 cup of vinegar (5% acidity) per gallon of water.
Deposits may be reduced if you add 1 tablespoon of white vinegar to the water in the canner for processing.
NCHFP says that sealing compound in unused lids should work well for at least 5 years from date of manufacture. Older lids/sealing compound may fail to seal.
Image from 123RF.com

29. Preparing Jars and Lids
Wash jars, lids and screw bands in hot, soapy water; rinse in hot water
Dry screw bands and set aside
Prepare lids as directed by manufacturer
new Ball/Kerr lids do not need preheating—just wash, rinse and keep at room temperature until ready to use; preheating will not harm
do not boil lids—can result in seal failure
Heat jars before filling to help prevent breakage
submerge jars in enough water to cover
bring water to simmer (180°F) and keep jars in hot water until ready to use
Preheating lids to soften the sealing compound was needed when the sealing compound was latex. In 1969, Ball switched to a Plastisol sealing compound. This year, Jarden Home Brands announced that extensive research has shown that preheating lids to soften the Plastisol compound is not needed for good seal formation. They have changed the instructions on their packaging to reflect this change. However, they do say that preheating will not harm the sealing compound. (Jarden Home Brands (2015), Canning Lids 101,
If preheating lids, heat in simmering water for 10 minutes and leave in hot water until ready to use.
Do not boil the lids—can result in seal failure.
Dishwasher may be used for washing and heating jars.
Images from National Center for Home Food Preservation

30. Additional Canning Utensils
Jar funnel
Headspace tool
Bubble freer—not metal!
Magnetic lid wand
Jar lifter
Clean cloths
Timer
Other utensils and equipment needed to prepare recipe (knives, cutting board, saucepans, hot pads)
Jar funnel for neater filling.
Headspace tool, if desired, to help ensure correct headspace.
Bubble freer for removing air bubbles from jars; a plastic knife or spatula will work—not metal!
Magnetic lid wand to remove prepared lids from hot water, if preheating.
Jar lifter for moving jars into and out of canner.
Clean cloths for wiping jar rims, general cleanup, and cooling jars.
Timer to accurately measure processing time.
Other utensils and equipment needed to prepare recipe (knives, cutting board, saucepans, hot pads).

31. Two Types of Canners Boiling Water Canner Pressure Canner 212°F
10 pounds pressure
Images from amazon.com
Granite Ware boiling water canner $17.97
Presto pressure canner $79.00

32. Which Canner to Use? Boiling Water Canner Pressure Canner
Tomatoes
Cucumbers
String beans 5.6
Beets
Cabbage
Corn
Grapes 2.8 – 3.8
Strawberries 3.0 – 3.9
Apples 3.3 – 4.0 Peaches 3.3 – 4.0
Determined by the acidity of the food—above or below pH 4.6?
Bacteria will not grow well at pH below 4.6
Boiling Water Canner
High Acid Foods
Pressure Canner
Low Acid Foods
4.6

33. High Acid vs. Low Acid Canned Foods
pH > 4.6
depend on heat processes under pressure to destroy the spores of Clostridium botulinum
Must use pressure canner
High acid (or acidified)
pH  4.6
depend on the pH of the food to prevent the growth of Clostridium botulinum
May use boiling water canner
Boiling water canner / High acid foods (pH below 4.6)
Fruits, jams, jellies, pickled fruits or vegetables, acidified tomatoes, salsa, barbecue sauce
Pressure canner / Low acid foods (pH above 4.6)
All vegetables, meat, poultry and fish

34. Steps to Safe Home Canning
Follow research-based recipes
Place the food in hot, prepared jars, leaving the correct headspace; remove air bubbles
Wipe jar rims; adjust two-piece caps; tighten lids until fingertip tight only
Heat the filled jars to the specified temperature for the food, using the right type of canner
Process jars for the specified time to inactivate enzymes and destroy harmful bacteria and spoilage microorganisms
Altitude affects processing times and pressures
Cool jars properly so a vacuum seal forms
Higher altitudes (water boils at lower temperature) require longer processing time for boiling water canner, higher pressure for pressure canner.
After processing and during cooling, a vacuum is formed inside the jar that seals the lid onto the jar. As long as the jars are stored properly and remained sealed, the home canned food should be free of spoilage, and the seal prevents recontamination of food.
Images from 123RF.com

35. Low acid foods: All vegetables, meat, poultry and fish
Two Types of Canners
Boiling Water Canner
212°F
Pressure Canner
10 pounds pressure
Images from amazon.com
Granite Ware boiling water canner $17.97
Presto pressure canner $79.00
High acid foods: Fruits, jams, jellies, pickled fruits or vegetables, acidified tomatoes, salsa, barbecue sauce
Low acid foods: All vegetables, meat, poultry and fish

36. Boiling Water Canner
Fill canner half full of clean warm water; place rack in bottom; preheat water to simmering (180°F)
Prepare recipe and fill jars
Using a jar lifter, load jars into canner one at a time, keeping them upright at all times
Add more boiling water if needed so that water level is 1-2 inches above jar tops
Place lid on canner; turn up heat
When water returns to a boil, begin timing; adjust heat to maintain a gentle but complete boil for entire processing time
At end of processing time, turn off heat and remove canner lid; wait 5 minutes before removing jars from canner
Using a jar lifter, remove jars from canner, keeping them upright
Set jars on a towel on counter to cool; leave undisturbed for hours (as jars cool, vacuum seal forms)
Boiling water canner can be any large pot with a fitted lid, deep enough to allow boiling water to cover jar tops by 1-2 inches. Should have a rack in the bottom, to keep jars off the bottom of the pot (folded towel can be used).
If you have an electric stove, you will need a canner with a flat bottom. A boiling water canner that has either a flat or ridged bottom may be used on a gas stove.
Keep jars upright at all times when loading and unloading canner to prevent food from spilling into the sealing area and interfering with the final seal.
If water stops boiling at any time during the process, increase the heat to return to a complete boil and start the timing of the process all over again.
Label jars.
Store in a cool, dry, dark place for up to two years.

37. Hands-on Canning Activity: Corn Relish
Recipe adapted from Ball Blue Book, page 53 (half recipe)
Vinegar used to increase acidity to level safe for boiling water canning (pH  4.6)
Using half-pint jars in place of pints; processing time cannot be reduced; use full pint jar processing time
Read through entire recipe before beginning

38. Pressure Canner
Fill canner with 1-2 inches of water, following the manufacturer’s instructions
Prepare recipe and fill jars; load jars into canner and secure canner lid; leave weight off vent port
Turn up heat and vent canner for 10 minutes to remove trapped air; place counterweight or weighted gauge over vent port to begin building pressure in the canner
Bring pressure up to that specified in recipe
Begin timing process as indicated in recipe; adjust heat to maintain steady pressure for entire processing time
At end of processing time, turn off heat and allow canner to cool naturally to return to zero pressure; then remove weight from vent port (Canner and contents are still very hot!)
Wait 10 minutes; remove lid carefully; remove jars
Set jars on a towel on counter to cool; leave undisturbed for hours (as jars cool, vacuum seal forms)
Pressure canners made after 1997 have been redesigned with more safety features.
Follow manufacturer’s instructions regarding care and maintenance.
Two types: Dial gauge or weighted gauge.
Dial gauge should be checked for accuracy annually. Weighted gauge should maintain its accuracy, as long as you don’t drop it or let the vent get plugged.
Pressure required depends on altitude (10-11 pounds for most places in KY).
Pressure in dial gauge canner can be read on gauge. Correct pressure in weighted gauge canner is indicated by the weight jiggling or rocking as specified in manufacturer’s instructions.
Pressure must be maintained for the entire processing time. If it falls below the specified level, increase heat to bring the pressure back up and start timing of the process all over again.
Quick and large pressure variations during processing may cause unnecessary liquid losses from jars.
Forced cooling before the canner is fully depressurized will cause loss of liquid from jars, failed seals. May cause food spoilage and also warp the canner lid.
Label jars.
Store in a cool, dry, dark place for up to two years.

39. After Processing
Allow jars to cool, undisturbed, for hours to allow vacuum to form
After 24 hours, test to be sure that jars are sealed
most two-piece lids will seal with a “pop” while they’re cooling
sealed lid will be curved downward and should not move when pressed with finger
Remove screw bands to prevent them from rusting on during storage
Wash outside of jars and lid surfaces
Date and label jars and store in cool, dry place for up to two years
If liquid has been lost from sealed jars, do not open them to replace it. Plan to use those jars first. The food may discolor, but if sealed and properly processed, and if the liquid is only a little lower than the food, the food should be safe to eat.
If more that half the liquid is lost, refrigerate and eat within a few days.

40. Unsealed Jars
If a jar is not sealed, refrigerate and use within two to three days
Freeze the food for longer storage
Unsealed jars can be reprocessed within 24 hours
remove lid and check jar rims for nicks
change jar if necessary
add new, properly prepared lids
reprocess for the full processing time specified in the recipe
Images from 123RF.com (2), Amazon.com

41. Sources of Bacterial Spoilage
Incipient spoilage
food held too long before canning
allows spoilage to start before canning occurs
Inadequate heat processing
insufficient time or temperature to kill all bacteria and/or spores present in the food
bacterial growth continues after processing
Contamination after processing
before vacuum seal is complete
Thermophilic bacterial spoilage
improper cooling
storage above 95°F
Spoilage may take several weeks to become apparent.
Inadequate heat processing can be very dangerous—processing times and jar sizes specified in recipe must be followed.
Most thermophilic bacteria affect food quality, not safety. Spores are very heat-resistant. Grow best at F—after processing, cool canned foods promptly and store below 95F.

42. Signs of Bacterial Spoilage
Do not taste any foods that show the following signs:
Unsealed jar or bulging lid
Dried food on outside of jar, indicating seepage
Rising air bubbles
Cloudiness
Spurting liquid when opened
Disagreeable odor
Mold growth on food surface or underside of lid
Remember that harmful bacteria can be present without any signs of spoilage, if the home-canned product was improperly processed!

43. One More Time… Low acid foods High acid foods pH  4.6 pH  4.6
All fresh vegetables, red meats, seafood, poultry, eggs, milk, soups and stews
Process at 240°F for specified time
Pressure canner
High acid foods
pH  4.6
Fruit, pickles, relishes, jams, jellies, fruit butters, salsa, tomatoes acidified with lemon juice or citric acid
Process at 212°F for specified time
Boiling water canner
High acid canned foods depend on acidity to prevent germination and growth of any Clostridium botulinum spores that might be present.
Low acid canned foods depend on the high temperature in the pressure canner to kill any spores of Clostridium botulinum that might be present.
Images from 123RF.com

44. What’s New in Home Canning?
Ball® FreshTECH Automatic Home Canning System
Ball® FreshTECH Automatic Jam & Jelly Maker
Ball® FreshTECH Electric Water Bath Canner and Multi-Cooker
Ball® Sure TightTM Band Tool
Automatic Home Canning System:
Boiling water canner only—not a pressure canner!
Use only recipes developed for the automatic canner.
Small capacity (6 half-pints, 4 pints or 3 quarts).
Automatic Jam & Jelly Maker:
Cooks the jam or jelly (cook fruit, pectin and butter; signal to gradually add sugar; finish cooking).
Freeze or boiling water bath to preserve.
Electric Water Bath Canner and Multi-Cooker
Replaces stovetop boiling water canner.
Larger capacity (7 quarts or 8 pints).
Should be able to use any tested boiling water canning recipe.

45. DRYING FOODS AT HOME

46. Food Drying/Dehydrating
One of the oldest methods of food preservation
Preserves food by removing the moisture that bacteria and other microorganisms (yeasts, molds) need to grow (FAT TOM)
Enzyme action is slowed (but not stopped); helps maintain color, texture and quality

47. What Can You Dry? Fruits Vegetables Leathers Herbs Nuts and seeds
Meat jerkies
Images from:
123RF com
National Center for Home Food Preservation (leather)

48. Drying Methods ~ Outdoor
Sun drying
fruits; a few vegetables
needs hot, dry, breezy weather
Solar drying
dryer magnifies sun’s heat
Vine drying
beans, lentils and soybeans
leave pods on vines until they rattle
Pasteurization required to kill insects and eggs
freezer (0°F for 48 hours or longer)
oven (160°F for 30 minutes)
Fruits – high in sugar and acid
These vegetables: whole peppers, beans, peas
Images from National Center for Home Food Preservation website(2), 123RF.com

49. Drying Methods ~ Indoor
Room drying
herbs, nuts, chili peppers
sunny room, low humidity, air movement
Oven drying
most foods
need low temperature ( °F)
oven door open, fan for air movement; high energy use
Dehydrator drying
high quality, sanitary, fast
Room drying – string herbs or peppers
- spread nuts in single layer on paper, tray or in paper bag
Images from 123RF.com

50. Drying Fruits Uniform pieces; peeled and thinly sliced dry fastest
Pretreat to prevent darkening
burning sulfur; no longer recommended
sulfite or ascorbic acid dip
fruit juice or honey dip; adds flavor and calories
blanching in syrup or steam
Dry in single layer for recommended time at 135°F
When dried (20% moisture)
no visible moisture
may remain pliable, but not sticky
cool 30 – 60 minutes before packaging
Condition 7 – 10 days to evenly distribute moisture
Dried to about 20% moisture.
Condition in loosely packed plastic or glass jars, shaking daily.
Image from 123RF.com

51. Drying Vegetables Uniform pieces
Pretreat to inactivate enzymes and set color
water blanching
steam blanching
Dry in single layer for recommended time at 130°F
When dried (10% moisture)
most will be brittle or crisp
(beans, corn, onions, celery)
some will be leathery
(tomatoes, carrots, mushrooms)
cool before packaging
No need to condition (very low moisture)
Dried to 10% moisture.
Image from 123RF.com

52. Fruit & Vegetable Leathers
Use fresh, frozen or drained canned fruit
Use tomatoes, pumpkin puree, or mixed vegetables (tomato, onion, celery)
Combine fruits or vegetables to mix flavors
Puree fruits or vegetables until smooth
Add lemon juice or ascorbic acid to prevent browning (light-colored fruit)
Sweeten if desired (sugar, honey or corn syrup)
Pour 1/8 – 1/4 inch thick layer; dry at 140°F
When dried
no indentation when touched
peel from tray when warm to prevent sticking
Apple-blueberry leather: 2 cups unsweetened applesauce + ½ cup thawed wild blueberries; pureed in blender; dried ~ 12 hours—too long?
Spread thicker (1/4 inch) at edge, thinner at center (1/8 inch)—outside edge dries first.
To store, roll and wrap in plastic.
Will keep up to 1 month at room temp—freeze for longer storage
Image from National Center for Home Food Preservation

53. Drying Herbs Harvest before flowers open Room drying Dehydrator drying
bundle and tie; hang in warm, dry well-ventilated room
hang tender herbs inside paper bags with holes in sides
Dehydrator drying
dry in single layer at 95 – 115°F
Oven drying
leaves only (mint, sage, bay leaf)
up to 5 layers between paper towels in very cool oven
When dried
leaves crumble
stems break when bent
Sturdy : rosemary, sage, thyme, parsley
Tender: basil, oregano, tarragon, mint
Very cool oven: light bulb in electric oven; pilot light in gas oven
Image from 123RF.com

54. Storing Dried Foods Cool completely before packaging
Seal out air and moisture
clean, dry canning jars
plastic freezer containers with tight-fitting lids
plastic freezer bags
vacuum packaging
Store in cool, dry, dark area
Recommended storage time: months to 1 year, depending on the food
Pack in amounts that will be used all at once or in a single recipe (to reduce exposure to air and moisture from opening and re-opening package)
Image from 123RF.com

55. HOME FREEZING BASICS

56. Freezing Food One of the easiest methods of home food preservation
Preserves food by using low temperatures to prevent the growth of bacteria and other microorganisms; also lowers Aw (FAT TOM)
Slows down chemical changes that affect quality or cause food spoilage
Does not kill bacteria or other microorganisms—on thawing, any bacteria present will begin to grow and may cause spoilage or illness
Does not destroy enzymes that cause color and flavor changes—just slows them down
Freezing lowers water activity by tying up water molecules so they are no longer available for bacterial growth.

57. What Can You Freeze? Fruits Most vegetables Meats, poultry and seafood
Dairy foods
Eggs
Nuts
Prepared or cooked foods
Images from 123RF.com

58. Foods That Don’t Freeze Well
Some vegetables (e.g. cabbage, celery, lettuce, cucumbers, radishes)
Some dairy foods (e.g. sour cream, meringue, custards, milk sauces)
Cooked macaroni, spaghetti or rice
Mayonnaise or salad dressing
Gelatin
Spices, herbs and seasonings
Most fried foods
Vegetables become limp, water-logged; off color, smell and texture. Cabbage and cucumbers can be frozen as marinated products such as “freezer slaw.” Do not have the same texture as regular slaw or pickles.
Dairy foods may curdle or separate. Meringue toughens.
Macaroni, etc. may get mushy, taste warmed over.
Mayonnaise separates.
Gelatin weeps.
Spices, etc. may develop off flavor, get strong and bitter. Salt loses flavor, may increase rancidity of food containing fat.
Fried foods lose crispness, become soggy (except french fries, onion rings).
Images from 123RF.com

59. Freezing Basics Start with top quality foods
freezing will not improve flavor or texture
Work under sanitary conditions
Follow directions for each individual food
Package to keep air out, moisture in
helps maintain flavor and nutritive value
Label and date each package
Freeze foods quickly
cool all foods before packaging
don’t overload freezer with unfrozen food
allow space between packages for air circulation
Freeze foods to 0°F or lower
Freeze quickly—smaller ice crystals = less damage to cell walls.
Generally, freeze 2-3 pounds food per cubic food of freezer space per 24 hours. See manual for specific freezer.
Once food is frozen, packages can be more tightly packed.
Freezer burn does not make food unsafe, but causes loss of quality.
Upright and chest freezers will reach 0F or lower. Not all refrigerator-freezers will.
Images from 123RF.com .

60. Containers for Freezing
Freezer is a dry climate
Choose containers or packaging that will protect the flavor, color, moisture content and nutritive value of food
Look for:
moisture-, vapor-, oil- and water-resistant materials
durable and leak-proof
will not crack at low temperatures
easy to seal
easy to mark
half-gallon size or less, for quicker freezing
Image from MS Office Clip Art

61. Types of Containers/Packaging
Rigid containers
plastic or tempered glass
tight-fitting lids
straight sides desirable
headspace allows for expansion of food during freezing
Flexible bags or wrappings
plastic bags or wrap, freezer paper, or heavy-weight aluminum foil
press to remove as much air as possible before closing (except for headspace)
Vacuum packaging
keep food frozen until ready to use (risk of botulism from some vacuum-packaged foods)
Headspace:
Liquid pack -wide opening ½ - 1 inch (pint-quart)
-narrow opening ¾ - 1½ inches (pint-quart)
Dry pack ½ inch
Can reinforce seal of lid with freezer tape.
Images from 123RF.com

62. Freezing Fruits
Select fruit of best quality (firm, ripe, at peak of freshness)
Enzymes can cause browning and loss of vitamin C
controlled by chemical compounds (ascorbic acid most effective)
Follow specific directions for each type of fruit
Types of packs
syrup pack—better texture and flavor for most fruits
sugar pack—better texture and flavor for most fruits
dry pack or tray pack—good for small whole fruits such as berries
unsweetened packs—water, unsweetened juice, or pectin syrup; may use sugar substitutes
Citric acid and lemon juice are not as effective as ascorbic acid.
Fruits are not usually blanched before freezing, but steam blanching can be used for fruits that will be cooked before use.
Dry pack—pack fruit into a container, seal, and freeze.
Tray pack—freeze pieces or whole small fruit individually in a single layer on tray until firm, then package in rigid container or bag. Fruit pieces remain loose and can be more easily removed from container.
Unsweetened packs generally yield a product that does not have the plump texture and good color of those packed with sugar. Better for some fruits than others (e.g. raspberries, blueberries, cranberries, steamed apples, rhubarb)
Image from 123RF.com

63. Freezing Vegetables
Select vegetables of best quality (fresh, young, tender)
Enzymes can cause loss of flavor, color and texture
controlled by blanching in boiling water or steam, followed by rapid cooling
blanching is a must for almost all vegetables
blanching cleans surface, brightens color, helps slow loss of vitamins, softens hard veggies for easier packaging
blanching time is crucial and varies with the vegetable and size
Follow specific directions for each type of vegetable
Dry pack or tray pack
Under blanching stimulates enzyme activity and is worse than no blanching.
Over blanching causes loss of flavor, color, vitamins and minerals.
Image from MS Office Clip Art

64. Freezing Meat, Poultry and Seafood
Select only high quality, fresh products
Follow directions for specific products
Package meats in moisture-proof freezer paper or wrap, wrapping tightly and sealing well
If packaging in store wrap, overwrap with suitable freezer wrap
Package in meal-size portions
Label and freeze immediately
Do not stuff poultry before freezing
Package shellfish in rigid containers or freezer bags
Image from 123RF.com

65. Storing Frozen Foods Freezer temperature: 0°F or lower
check temperature periodically with thermometer
avoid temperature fluctuations
For best quality, observe recommended storage times for frozen foods
after these times, food should still be safe—just lower in quality
Arrange foods so that food frozen longer can be used first
Keep a frozen food inventory up to date
Loss of quality during freezer storage is faster at warmer temperatures:
Same loss of quality in frozen beans stored for 1 year at 0F will occur in 3 months at 10F, in 3 weeks at 20F, and in 5 days at 30F (all while frozen).
Fluctuating temperatures cause partial thawing and refreezing—ice crystals get larger and affect texture.
Image from MS Office Clip Art

66. Thawing Foods for Serving
Fruits
thaw in refrigerator, in microwave oven, at room temperature, or in a pan of cool water
Vegetables
most should be cooked without thawing first
Meat, fish and poultry
can be cooked frozen or thawed
best thawed in refrigerator in original wrapping
can be thawed in cold water
can be thawed in microwave, if cooked immediately after thawing
Butter, eggs, milk, cheese and cream
thaw in refrigerator
Fruits: for better texture, serve frozen fruits while there are still a few ice crystals.
Image from 123RF.com

67. WHERE DO I GO FOR ANSWERS?

68. Research-based Information on Home Food Preservation
So Easy to Preserve (University of Georgia)
National Center for Home Food Preservation website
Ball Blue Book Guide to Preserving
UK Cooperative Extension publications
Home Canning series
Drying Food at Home
Home Freezing series
USDA Guide is available for free download from the NCHFP website.
So Easy to Preserve is available from the University of Georgia for $18, including shipping.
Ball Blue Book is available from a variety of sources for $ We purchase from the Fresh Preserving Store for $6.49 plus shipping.

69. Questions? References Images from
Andress, E. L., and J. A. Harrison (2011). So Easy to Preserve (6th ed.). Athens, GA: University of Georgia
National Center for Home Food Preservation website
United States Department of Agriculture (2009). USDA Complete Guide to Home Canning (Agriculture Information Bulletin No. 539).
Images from
Microsoft Office Clip Art
123RF Stock Images
National Center for Home Food Preservation
February 2015
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