LIDS THAT DO NOT SEAL:
Not following manufacturer's directions
Using an old lid or ring
Flaw in jar- nick, crack or uneven closure
Overtightening of jar lids - must allow for air to escape to create a vacuum
Sudden fluctuations in pressure canner temperature
Rusty or bent screwbands
Lack of heat in processing
Siphoning of liquid leaving food particles lodged on lip
Faulty lids or rings
Improper headspace in the jars
Overprocessing in rapidly boiling water
Displacement of air space fruit absorbs air, or air not sufficiently removed

Jars that are not sealed may be stored in the refrigerator and used within
a week or two. To reprocess the food check for jar flaws, add new lid
and reprocess again for the full amount of time.

HOME CANNED TOMATO JUICE THAT SEPARATES:
Home-canned tomato juice usually separates. This is because it is made by
the "cold break" method, to use the food scientist's terminology. The tomatoes
are crushed before they are heated through. As soon as they are crushed,
enzymes start to break down the pectin that "cements" tomato cells together.

Commercially, tomato juice is extracted by the "hot break" method. The
tomatoes are heated nearly to boiling in a matter of seconds, not minutes.
With the "hot break" method, enzymes that break down pectin are destroyed
before they have a chance to act. Because the pectin holding tomato cells
together remains intact, a thick-bodied, homogeneous juice is produced.

It is hard to duplicate the "hot break" method at home. The best that can be
done is to heat quartered tomatoes to simmering temperatures (180-190°F)
as fast as possible, while stirring. Then put them through a strainer. The least
desirable way to make tomato juice is to put raw tomatoes in a blender.
Blending raw tomatoes encourages the enzymatic breakdown of pectin. It
also incorporates air into the juice, resulting in oxidative destruction of vitamin C.

FRUIT TURNING DARK:
Fruit not processed long enough
Processing temperature not hot enough
Packing fruits raw, which should be hot packed (pears, apples, pineapple)
Fruit floating out of liquid
Oxidation of fruit
Too long a time period between cutting and processing

CANNING FRUITS AND FRUIT JUICES
LOSS OF LIQUID FROM JAR AFTER  PROCESSING:
CAUSE: Food packed to tightly, causing boiling over
PREVENTION: Pack Food loosely

CAUSE: Air bubbles in jar
PREVENTION: Remove air bubbles with a spatula

CAUSE: Jars not covered with water in water bath canner
PREVENTION: Have at least 1 inch of water covering jars in water bath

If a good seal is formed, the food is still safe, although probably not very
attractive. Never attempt to replace liquid without reprocessing.

JAR SEALS INITIALLY- THEN SEAL IS BROKEN:
CAUSE: Growth of organisms in jar due to underprocessing
PREVENTION: Process properly

CAUSE: Crack in jar
PREVENTION: Use sound jars

CAUSE: Food particles on sealing surface of lid
PREVENTION: Wipe rim and threads of jar before sealing

If a seal has been broken for an unknown amount of time, the food has
probably begun to spoil. If broken seal is detected within 24 hours of
canning, food may be used or reprocessed.

CLOUDY LIQUIDS:
CAUSE: Bacterial spoilage
PREVENTION: Process properly

CAUSE: Minerals in water
PREVENTION: Use soft water

CAUSE: Anti-caking agents from table salt
PREVENTION: Use canning salt

With bacterial spoilage, liquid is usually murky and food is soft. If there
is microbiological spoilage, destroy the food.

FERMENTATION. GAS FORMED IN JAR - SEAL MAY
BE BROKEN. BUBBLES USUALLY APPARENT AND
THERE MAY BE A CHESSY, ALCOHOLIC ODOR:
CAUSE: Yeast
PREVENTION: With proper processing yeast is easily destroyed by heat.
Avoid Open-Kettle method.

This type of spoilage will generally develop within a few days after canning.
Yeast is more susceptible to heat in an unsweetened food. If microbiological
spoilage occurs, destroy food.

GASSY AND FROTHY, BAD ODOR:
CAUSE: Acid-tolerant bacteria
PREVENTION: Process properly. Use clean equipment and food.

This type of spoilage generally develops with a few days after canning. If
microbiological spoilage occurs, destroy food.

MEDICINAL, SOUR OR BITTER FLAVOR. NO GAS.
GENERALLY OCCURS IN TOMATOES:
CAUSE: Bacteriathermophilic (optimum temperature above 113°F)
PREVENTION: Process properly. Use clean equipment and food. Cool
food quickly and store at room temperature.

With bacterial spoilage, liquid is usually murky and food is soft. If there is
microbiological spoilage, destroy food.

FUZZY GROWTH ON SURFACE OF FOOD. MUSTY ODOR.
OFTEN FOOD IS SLIMY: USUALLY  APPARENT AND THERE
MAY BE A CHESSY, ALCOHOLIC ODOR:
CAUSE: Mold
PREVENTION: Proper processing. Avoid Open-Kettle method.

By-products of molds and mycotoxins may be toxic or carcinogenic. Large
amounts of mold may decrease the acidity of the food so other microorganisms
may grow. If microbiological spoilage occurs, destroy food.

DARKENING AFTER REMOVAL FROM JAR:
CAUSE: Enzymes
PREVENTION: Process long enough to inactivate enzymes

This would indicate gross underprocessing.

PINK, RED, BLUE OR PURPLE COLOR IN CANNED
APPLES, PEARS, PEACHES AND QUINCES:
CAUSE: Natural chemical change with heat
PREVENTION: None

This may vary with the variety of fruit.

CRYSTAL IN GRAPE PRODUCTS:
CAUSE: Tartaric acid naturally present in grape
PREVENTION: Reprocess juice original length of time

Reprocessing dissolves the crystals.

FLOATING FRUIT:
CAUSE: Packed too loosely
PREVENTION: Use hot pack method

CAUSE: Fruit is lighter than syrup
PREVENTION: Use ripe fruit; use medium or light syrup

Heating drives oxygen from tissues.

CORRODED LIDS, DARK COLOR  DEVELOPS ON PART
OF LID EXPOSED TO FOOD:
CAUSE:  Reaction of acid with metal lid
PREVENTION: None - possibly reduced by not over filling

No harm results unless corrosion has been extensive enough to cause the
seal to fail.

BLACK, BROWN OR GRAY COLORS IN FOOD:
CAUSE: Substances in food react with minerals in water or metal utensils
PREVENTION: Use soft water; avoid using copper, iron, or chipped
enamel utensils

This may vary with the variety of the fruit.

LOSS OF LIQUID FROM JARS:
Fluctuation of the pressure in the pressure canner
Hurrying the cooling of the pressure canner
Improper headspace in the jars
Overprocessing in rapidly boiling water
Displacement of air space - fruit absorbs air, or air not sufficiently removed

If foods have lost liquid during the canning process, but the lids are sealed,
they are safe to eat. HOWEVER, food above the liquid may turn dark, soften
or dry out.