Unwelcome Dinner Guest:
Preventing Food-Borne Illness
Chart of Disease-Causing Organisms
"It must be something I ate,"
is often the explanation people give for a bout of home-grown "Montezuma's
Revenge" (acute diarrhea) or some other unwelcome gastrointestinal upset.
Despite the fact that America's
food supply is the safest in the world, the unappetizing truth is that
what we eat can very well be the vehicle for food-borne illnesses that
can cause a variety of unpleasant symptoms and may be life-threatening
to the less healthy among us. Seventy-six million cases of food-borne
diarrheal disease occur in the United States every year.
The Food and Drug Administration
has given high priority to combating microbial contamination of the food
supply. But the agency can't do the job alone.
Consumers have a part to play,
especially when it comes to following safe food-handling practices in
The prime causes of food-borne
illness include bacteria, parasites and viruses such as: Escherichia
coli O157:H7, Campylobacter jejuni, Salmonella,
Staphylococcus aureus, Listeria monocytogenes, Clostridium botulinum,
Clostridium perfringens, Vibrio parahaemolyticus, Vibrio vulnificus
and Shigella. Viruses, such as hepatitis
A virus and noroviruses, can also cause foodborne illness. Parasites are
another origin of this type of illness and include Giardia
lamblia, Cyclospora cayetanensis, and Cryptosporidium
These organisms can become
unwelcome guests at the dinner table. They're in a wide range of foods,
including meat, milk and other dairy products, spices, chocolate, seafood,
and even water.
Specific foods that have been
implicated in foodborne illnesses are unpasteurized fruit and vegetable
juices and ciders; raw or undercooked eggs or foods containing undercooked
eggs; chicken, tuna, potato and macaroni salads; cream-filled pastries;
and fresh produce.
Bacteria such as
Listeria monocytogenes, Vibrio vulnificus, Vibrio parahaemolyticus
and Salmonella have been found in raw seafood.
Oysters, clams, mussels, scallops, and cockles may be contaminated with
hepatitis A virus.
Careless food handling sets
the stage for the growth of disease-causing "bugs." For example, hot or
cold foods left standing too long at room temperature provide an ideal
climate for bacteria to grow. Improper cooking also plays a role in food-borne
Foods may be cross-contaminated
when cutting boards and kitchen tools that have been used to prepare a
contaminated food, such as raw chicken, are not cleaned before being used
for another food such as vegetables.
Common symptoms of foodborne
illness include diarrhea, abdominal cramping, fever, headache, vomiting,
severe exhaustion, and sometimes blood or pus in the stools. However,
symptoms will vary according to the type of organism and the amount of
In rare instances, symptoms
may come on as early as a half hour after eating the contaminated food
but they typically do not develop for several days or weeks. Symptoms
of viral or parasitic illnesses may not appear for several weeks after
exposure. Symptoms usually last only a day or two, but in some cases can
persist a week to 10 days. For most healthy people, food-borne illnesses
are neither long-lasting nor life-threatening. However, they can be severe
in the very young, the very old, and people with certain diseases and
These conditions include:
- liver disease, either from
excessive alcohol use, viral hepatitis, or other causes
- hemochromatosis, an iron
- stomach problems, including
previous stomach survery and low stomach acid (for example, from antacid
- immune disorder, including
- long-term steroid use,
as for asthma and arthritis.
When symptoms are severe,
the victim should see a doctor or get emergency help. This is especially
important for those who are most vulnerable. For mild cases of foodborne
illness, the individual should drink plenty of liquids to replace fluids
lost through vomiting and diarrhea.
The idea that the food on
the dinner table can make someone sick may be disturbing, but there are
many steps you can take to protect your families and dinner guests. It's
just a matter of following basic rules of food safety.
Prevention of food poisoning
starts with your trip to the supermarket.
- Pick up your packaged and
canned foods first.
- Don't buy food in cans
that are bulging or dented or in jars that are cracked or have loose
or bulging lids.
- Don't eat raw shellfish
and use only pasteurized milk and cheese and pasteurized or otherwise
treated ciders and juices if you have a health problem, especially one
that may have impaired your immune system.
- Choose eggs that are refrigerated
in the store. Before putting them in your cart, open the carton and
make sure that the eggs are clean and none are cracked.
- Select frozen foods and
perishables such as meat, poultry or fish last. Always put these products
in separate plastic bags so that drippings don't contaminate other foods
in your shopping cart.
- Don't buy frozen seafood
if the packages are open, torn or crushed on the edges. Avoid packages
that are above the frost line in the store's freezer. If the package
cover is transparent, look for signs of frost or ice crystals. This
could mean that the fish has either been stored for a long time or thawed
- Check for cleanliness at
the meat or fish counter and the salad bar. For instance, cooked shrimp
lying on the same bed of ice as raw fish could become contaminated.
- When shopping for shellfish,
buy from markets that get their supplies from state-approved sources;
stay clear of vendors who sell shellfish from roadside stands or the
back of a truck. And if you're planning to harvest your own shellfish,
heed posted warnings about the safety of the water.
- Take an ice chest along
to keep frozen and perishable foods cold if it will take more than an
hour to get your groceries home.
- The first rule of food
storage in the home is to refrigerate or freeze perishables right away.
The refrigerator temperature should be 40 degrees Fahrenheit (5 degrees
Celsius), and the freezer should be zero degrees F (minus 18 degrees
C). Check both "fridge" and freezer periodically with a refrigerator/freezer
- Poultry and meat heading
for the refrigerator may be stored as purchased in the plastic wrap
for a day or two. If only part of the meat or poultry is going to be
used right away, it can be wrapped loosely for refrigerator storage.
Just make sure juices can't escape to contaminate other foods.
- Wrap tightly foods destined
for the freezer. Leftovers should be stored in tight containers.
- Store eggs in their carton
in the refrigerator itself rather than on the door, where the temperature
- Seafood should always be
kept in the refrigerator or freezer until preparation time.
- Don't crowd the refrigerator
or freezer so tightly that air can't circulate. Check the leftovers
in covered dishes and storage bags daily for spoilage. Anything that
looks or smells suspicious should be thrown out.
- A sure sign of spoilage
is the presence of mold, which can grow even under refrigeration. While
not a major health threat, mold can make food unappetizing. Most moldy
foods should be thrown out. But you might be able to save molding hard
cheeses, salami, and firm fruits and vegetables if you cut out not only
the mold but a large area around it. Cutting the larger area around
the mold is important because much of the mold growth is below the surface
of the food.
- Always check the labels
on cans or jars to determine how the contents should be stored. Many
items besides fresh meats, vegetables, and dairy products need to be
kept cold. For instance, mayonnaise and ketchup should go in the refrigerator
after opening. If you've neglected to refrigerate items, it's usually
best to throw them out.
- Some precautions will help
make sure that foods that can be stored at room temperature remain safe.
Potatoes and onions should not be stored under the sink because leakage
from the pipes can damage the food. Potatoes don't belong in the refrigerator,
either. Store them in a cool, dry place. Don't store foods near household
cleaning products and chemicals.
- Check canned goods to see
whether any are sticky on the outside. This may indicate a leak. Newly
purchased cans that appear to be leaking should be returned to the store,
which should notify the FDA.
Keep It Clean
The first cardinal rule of
safe food preparation in the home is: Keep everything clean.
The cleanliness rule applies
to the areas where food is prepared and, most importantly, to the cook.
- Wash hands with warm water
and soap for at least 20 seconds before starting to prepare a meal and
after handling raw meat or poultry.
- Cover long hair with a
net or scarf, and be sure that any open sores or cuts on the hands are
completely covered. If the sore or cut is infected, stay out of the
- Keep the work area clean
and uncluttered. Wash countertops with a solution of 1 teaspoon of chlorine
bleach to 1 quart of water or with a commercial kitchen cleaning agent
diluted according to product directions. They're the most effective
at getting rid of bacteria.
- Also, be sure to keep dishcloths
clean because, when wet, they can harbor bacteria and may promote their
growth. Wash dishcloths weekly in hot water in the washing machine.
- Sanitize the kitchen sink
drain periodically by pouring down the sink a solution of 1 teaspoon
of bleach to 1 quart of water or a commercial kitchen cleaning agent.
Food particles get trapped in the drain and disposal and, along with
the moistness, create an ideal environment for bacterial growth.
- Use smooth cutting boards
made of hard maple or a non-porous material such as plastic and free
of cracks and crevices. Avoid boards made of soft, porous materials.
Wash cutting boards with hot water and soap, using a scrub brush. Then,
sanitize them by washing in an automatic dishwasher or by rinsing with
a solution of 1 teaspoon of chlorine bleach to 1 quart of water.
- Always wash and sanitize
cutting boards after using them for raw foods, such as seafood or chicken,
and before using them for ready-to-eat foods. Consider using one cutting
board only for foods that will be cooked, such as raw fish, and another
only for ready-to-eat foods, such as bread, fresh fruit, and cooked
- Always use clean utensils
and wash them between cutting different foods.
- Wash the lids of canned
foods before opening to keep dirt from getting into the food. Also,
clean the blade of the can opener after each use. Food processors and
meat grinders should be taken apart and cleaned as soon as possible
after they are used.
- Do not put cooked meat
on an unwashed plate or platter that has held raw meat.
- Wash fresh fruits and vegetables
thoroughly, rinsing under running water. Don't use soap or other detergents.
If necessary--and appropriate--use a small scrub brush to remove surface
The second cardinal rule of
home food preparation is: Keep hot foods hot and cold foods cold.
- Use a digital or dial food
thermometer to ensure that meats are completely cooked. Insert the thermometer
into the center of the food and wait 30 seconds for accurate measurement.
Beef, lamb, and veal should be cooked to at least 145° F (63°
C); pork and ground beef to 160° F (71° C); whole poultry and
thighs to 180° F (82° C); poultry breasts to 170° F (77°
C); and ground chicken or turkey to 165° F (74° C).
- Eggs should be cooked until
the white and the yolk are firm. Avoid foods containing raw eggs, such
as homemade ice cream, mayonnaise, eggnog, cookie dough and cake batter,
because they carry a Salmonella risk. Their
commercial counterparts usually don't because they're made with pasteurized
eggs. Cooking the egg-containing product to an internal temperature
of at least 160° F (71° C) will kill the bacteria.
- Seafood should be thoroughly
cooked to an internal temperature of at least 145 F (63° C). Fish
that's ground or flaked, such as a fish cake, should be cooked to at
least 155° F (68° C), and stuffed fish to at least 165°
F (74° C).
If you don't have a meat thermometer,
look for other signs of doneness. For example:
- Fish is done when the thickest
part becomes opaque and the fish flakes easily when poked with a fork.
- Shrimp can be simmered
three to five minutes or until the shells turn red.
- Clams and mussels are steamed
over boiling water until the shells open (five to ten minutes). Then
boil three to five minutes longer.
- Oysters should be sautéed,
baked or boiled until plump, about 5 minutes.
Protect food from cross-contamination
after cooking, and eat it promptly.
- Cooked foods should not
be left standing on the table or kitchen counter for more than two hours.
Disease-causing bacteria grow in temperatures between 40 and 140°
F (4 and 60° C). Cooked foods that have been in this temperature
range for more than two hours should not be eaten.
- If a dish is to be served
hot, get it from the stove to the table as quickly as possible. Reheated
foods should be brought to a temperature of at least 165° F (74°
C). Keep cold foods in the refrigerator or on a bed of ice until serving.
This rule is particularly important to remember in the summer months.
- After the meal, leftovers
should be refrigerated as soon as possible. (Never mind that scintillating
dinner table conversation!) Meats should be cut in slices of three inches
or less and all foods should be stored in shallow containers to hasten
cooling. Be sure to remove all the stuffing from roast turkey or chicken
and store it separately. Giblets should also be stored separately. Leftovers
should be used within three days.
And here are just a few more
parting tips to keep your favorite dishes safe.
- Don't thaw meat and other
frozen foods at room temperature. Instead, move them from the freezer
to the refrigerator for a day or two; or defrost submerged in cold water.
You can also defrost in the microwave oven or during the cooking process.
Cook foods immediately after defrosting in the microwave or cold water.
- Never taste any food that
looks or smells "off" or comes out of leaking, bulging or severely damaged
cans or jars with leaky lids.
Though all these do's and
don'ts may seem overwhelming, remember, if you want to stay healthy, when
it comes to food safety, the old saying "rules are made to be broken"
does not apply!
Food and Drug Administration
the "Bad Bug
Book" and links about national
food safety programs.
Also see www.foodsafety.gov.
FDA's food information line at 1-888-SAFEFOOD (1-888-723-3366). Recorded
information 24 hours a day, every day. FDA public affairs specialists
are available to answer questions from 10 a.m. to 4 p.m. Eastern time,
Monday through Friday.
the FDA's Center for Food Safety and Applied Nutrition, Consumer Education
Staff (HFS-555), 5100 Paint Branch Parkway, College Park, MD 20740.
FDA's food safety video "Dirty Little Secrets: Kitchen Food Safety" for
$8.95. Call 202-861-0500 and ask for the duplication department or write
to: Interface Video Systems, P.O. Box 57138, Washington, DC 20037.
U.S. Department of
Call the USDA's meat
and poultry hotline at 1-800-535-4555 (TTY: 1-800-256-7072). Recorded
information in English and Spanish 24 hours a day, every day. Staffed
10:00 a.m. to 4:00 p.m. Eastern time, Monday through Friday.
Write to USDA, FSIS,
Food Safety Education Staff, Room 2932-S, 1400 Independence Ave., S.W.,
Washington, DC 20250.
Keep Your Food Safe
Always be sure to practice these four
simple steps to food safety:
CLEAN: Wash hands and surfaces
Wash your hands, cutting boards, dishes, utensils, and counter tops with
hot, soapy water before, during, and after preparing food.
SEPARATE: Don't cross-contaminate
Always keep raw meat, poultry, seafood and their juices away from other
COOK: Cook to proper temperatures
Use a food thermometer to make sure foods are cooked to a safe internal
CHILL: Refrigerate promptly
Be sure to refrigerate foods within two hours. Set your refrigerator no
higher than 40 F and the freezer at 0 F.
food safety messages from the Fight BAC public education campaign,
sponsored by the Partnership for Food Safety Education.
How Long Will It Keep?
Following is a rundown of storage guidelines
for some of the foods that are regulars on America's dinner tables.
Steaks and roasts
lean (such as cod)
fatty (such as blue, perch, salmon)
Swiss, brick, processed cheese
Eggs: fresh in shell
up to 6 months
Cheese can be frozen, but freezing will affect the texture and
(Sources: Food Marketing Institute for fish and dairy products,
USDA for all other foods.)
Publication No. (FDA) 99-2244
This article originally appeared
in the January-February 1991 FDA Consumer and contains revisions
made in December 1997, February and October 1999, June 2000, July 2002,
and March 2003.
For additional information, visit the Foodborne Illness Section.