Identifying and Handling Spoiled Canned Food
Do not taste food from a jar with an unsealed lid or food that shows signs of spoilage. You
can more easily detect some types of spoilage in jars stored without screw bands. Growth of
spoilage bacteria and yeast produces gas which pressurizes the food, swells lids, and breaks jar
seals. As each stored jar is selected for use, examine its lid for tightness and vacuum. Lids with
concave centers have good seals.
Next, while holding the jar upright at eye level, rotate the jar and examine its outside surface for
streaks of dried food originating at the top of the jar. Look at the contents for rising air bubbles
and unnatural color.
While opening the jar, smell for unnatural odors and look for spurting liquid and cottonlike mold
growth (white, blue, black, or green) on the top food surface and underside of lid.
Spoiled low-acid foods, including tomatoes, may exhibit different kinds of spoilage evidence or
very little evidence. Therefore, all suspect containers of spoiled low-acid foods, including
tomatoes, should be treated as having produced botulinum toxin and handled carefully in one of
•If the swollen metal cans or suspect glass jars are still sealed, place them in a heavy
garbage bag. Close and place the bag in a regular trash container or bury it in a nearby
•If the suspect cans or glass jars are unsealed, open, or leaking, they should be detoxified
Detoxification process: Carefully place the suspect containers and lids on their sides in an
8-quart volume or larger stock pot, pan, or boiling-water canner. Wash your hands thoroughly.
Carefully add water to the pot. The water should completely cover the containers with a minimum
of a 1-inch level above the containers. Avoid splashing the water. Place a lid on the pot and heat
the water to boiling. Boil 30 minutes to ensure detoxifying the food and all container components.
Cool and discard the containers, their lids, and food in the trash or bury in soil.
Thoroughly scrub all counters, containers, and equipment including can opener, clothing, and
hands that may have contacted the food or containers. Discard any sponges or wash cloths that
may have been used in the cleanup. Place them in a plastic bag and discard in the trash.
Preparing Pickled and Fermented Foods
The many varieties of pickled and fermented foods are classified by ingredients and method of
Regular dill pickles and sauerkraut are fermented and cured for about 3 weeks. Refrigerator dills
are fermented for about 1 week. During curing, colors and flavors change and acidity increases.
Fresh-pack or quick-process pickles are not fermented; some are brined several hours or
overnight, then drained and covered with vinegar and seasonings. Fruit pickles usually are
prepared by heating fruit in a seasoned syrup acidified with either lemon juice or vinegar.
Relishes are made from chopped fruits and vegetables that are cooked with seasonings and
Be sure to remove and discard a 1/16-inch slice from the blossom end of fresh cucumbers.
Blossoms may contain an enzyme which causes excessive softening of pickles.
Caution: The level of acidity in a pickled product is as important to its safety as it is to
taste and texture.
•Do not alter vinegar, food, or water proportions in a recipe or use a vinegar with
•Use only recipes with tested proportions of ingredients.
•There must be a minimum, uniform level of acid throughout the mixed product to
prevent the growth of botulinum bacteria.
Select fresh, firm fruits or vegetables free of spoilage. Measure or weigh amounts carefully,
because the proportion of fresh food to other ingredients will affect flavor and, in many instances,
Use canning or pickling salt. Noncaking material added to other salts may make the brine cloudy.
Since flake salt varies in density, it is not recommended for making pickled and fermented foods.
White granulated and brown sugars are most often used. Corn syrup and honey, unless called
for in reliable recipes, may produce undesirable flavors. White distilled and cider vinegars of 5
percent acidity (50 grain) are recommended. White vinegar is usually preferred when light color is
desirable, as is the case with fruits and cauliflower.
Pickles with Reduced Salt Content
Recipes for pickles with reduced sodium content are provided in Guide 6.
In the making of fresh-pack pickles, cucumbers are acidified quickly with vinegar. Use only tested
recipes formulated to produce the proper acidity. While these pickles may be prepared safely
with reduced or no salt, their quality may be noticeably lower. Both texture and flavor may be
slightly, but noticeably, different than expected. You may wish to make small quantities first to
determine if you like them.
However, the salt used in making fermented sauerkraut and brined pickles not only provides
characteristic flavor but also is vital to safety and texture. In fermented foods, salt favors the
growth of desirable bacteria while inhibiting the growth of others. Caution: Do not attempt to
make sauerkraut or fermented pickles by cutting back on the salt required.
Alum may be safely used to firm fermented pickles. However, it is unnecessary and is not
included in the recipes in this publication. Alum does not improve the firmness of quick-process
pickles. The calcium in lime definitely improves pickle firmness. Food-grade lime may be used as
a lime-water solution for soaking fresh cucumbers 12 to 24 hours before pickling them. Excess
lime absorbed by the cucumbers must be removed to make safe pickles. To remove excess lime,
drain the lime-water solution, rinse, and then resoak the cucumbers in fresh water for 1 hour.
Repeat the rinsing and soaking steps two more times. To further improve pickle firmness, you
may process cucumber pickles for 30 minutes in water at 180 F. This process also prevents
spoilage, but the water temperature should not fall below 180 F. Use a candy or jelly
thermometer to check the water temperature.
Pickle products are subject to spoilage from microorganisms, particularly yeasts and molds, as
well as enzymes that may affect flavor, color, and texture. Processing the pickles in a
boiling-water canner will prevent both of these problems. Standard canning jars and self-sealing
lids are recommended. Processing times and procedures will vary according to food acidity and
the size of food pieces.
Preparing Butters, Jams, Jellies, and Marmalades
Sweet spreads are a class of foods with many textures, flavors, and colors. They all consist of
fruits preserved mostly by means of sugar and they are thickened or jellied to some extent. Fruit
jelly is a semi-solid mixture of fruit juice and sugar that is clear and firm enough to hold its shape.
Other spreads are made from crushed or ground fruit.
Jam also will hold its shape, but it is less firm than jelly. Jam is made from crushed or chopped
fruits and sugar. Jams made from a mixture of fruits are usually called conserves, especially
when they include citrus fruits, nuts, raisins, or coconut. Preserves are made of small, whole
fruits or uniform-size pieces of fruits in a clear, thick, slightly jellied syrup. Marmalades are soft
fruit jellies with small pieces of fruit or citrus peel evenly suspended in a transparent jelly. Fruit
butters are made from fruit pulp cooked with sugar until thickened to a spreadable consistency.