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Recipe
directions often say to cook a food until "done." What is "done?"
While we
worry about cooking a food long enough for safety, we also should be concerned
about cooking it too long to taste good. We can assure 100 percent safety
if food is cooked until it tastes and looks like cardboard, a piece of
shoe leather or a hockey puck -- no one will eat it!
Websters
dictionary defines "doneness" as "the condition of being
cooked to the desired degree." Besides a safe temperature, another
aspect of "doneness" deals with subjective qualities such as
the appearance, texture and optimum flavor of a food.
Here are
some temperature guidelines, using U.S. Department of Agriculture (USDA)
and U.S. Food and Drug Administration (FDA) recommendations. These will
help ensure cooking to a "doneness" that is both SAFE and GOOD-TASTING.
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Using
a food thermometer is the only way to accurately determine a safe
internal temperature is reached.
Use
a clean thermometer that has been washed in hot soapy water and
hot rinse water before and after use. Most thermometers should not
be immersed in water -- check manufacturer's directions.
Insert
thermometer in the center at the thickest part of the food away
from bone, fat or gristle.
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INSERTING A
THERMOMETER
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| BEEF,
PORK or LAMB ROASTS. The food thermometer should be
placed midway in the roast, avoiding the bone. Irregularly
shaped foods, such as beef roasts, should have their temperature
checked in several places. |
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THINNER FOODS such as MEAT PATTIES, PORK CHOPS and
CHICKEN BREASTS. An instant-read thermometer may be
inserted sideways -- if necessary -- in the thickest part,
away from bone, fat, or gristle. Insert so the entire
sensing area is positioned through the center of the food.
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CASSEROLES and other COMBINATION DISHES. Place
a thermometer into the thickest portion of the food or
the center of the dish. Egg dishes and dishes containing
ground meat and poultry should be checked in several places.
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Check
manufacturer's instructions as to how far the thermometer must be
inserted in a food to give an accurate reading. If instructions
are not available, check the stem of the thermometer for an indentation
or "dimple" that shows the end of the sensing device.
The probe must be inserted the full length of the sensing area (usually
2 to 3 inches). If measuring the temperature of a thin food, such
as a hamburger patty or boneless chicken breast, the probe should
be inserted through the side of the food so the entire sensing area
is positioned through the center of the food.
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COMMON FOOD THERMOMETERS
Some
types of thermometers commonly used in the kitchen include:
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Designed
to stay in food during cooking. Insert 2 to 2 1/2 inches
deep in the thickest part of the food, at the beginning
of the cooking time. It remains there throughout cooking
and is not appropriate for thin food. |
Dial
Oven-Safe
(Bimetal)
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Not
designed to stay in food during cooking. Insert probe
the full length of the sensing area, usually 2 to 2
1/2 inches. If measuring the temperature of a thin food,
such as a hamburger patty or boneless chicken breast,
insert probe sideways with the sensing device in the
center. About 15 to 20 seconds are required for the
temperature to be accurately displayed.
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Dial
instant-read
(Bimetal) |
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Not
designed to stay in food during cooking. The heat sensing
device is in the tip of the probe. Place the tip of the
probe in the center of the thickest part of the food,
at least 1/2 inch deep. About 10 seconds are required
for the temperature to be accurately displayed.
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Digital
Instant-read
(Thermistor) |
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Frequently
used in foods such as roasts and turkeys during cooking
in the oven. The base unit sits on stovetop or counter
and the thermometer probe is placed in the food. An
advantage of this thermometer is the ease of tracking
food temperatures while maintaining oven heat.
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| Oven
Cord |
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Designed
to be used only once for a specific temperature range.Temperature-sensitive
material changes color when the desired temperature
is reached. Should only be used with food for which
they are intended. Place approximately 1/2" deep
(follow manufacturer's directions). Reads in 5-10 seconds.
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Disposable
Temperature Indicators
(Single-use) |
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TIPS
FOR USING THERMOMETERS
To
prevent overcooking, begin checking the temperature
toward the end of cooking but before the food is expected
to be "done."
Bacteria
normally are found only on the external surface of larger
cuts of meat like beef roasts and beef steaks. Beef
roasts and beef steaks can be considered safe if cooked
to 145 F in the center since the outside will reach
a temperature high enough to kill bacteria on the surface.
When meat is ground up or mechanically tenderized, bacteria
on the surface can get mixed throughout the meat and
the meat must be cooked to an internal temperature of
160 F. Mechanically tenderized meat has been punctured
or injected, which can introduce bacteria into the center
of the meat.
When
foods are cooked to less than 160 F, wait until toward
the end of the cooking period before inserting a thermometer.
Otherwise, it is possible bacteria from the outside
could be transmitted to the inside.
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A thermometer
is a little like a magic wand that helps transform foods into tasty, temperature-safe
creations. Following are instructions and tips for using a thermometer
successfully.
RECOMMENDED
FOOD TEMPERATURES
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Celsius
Conversion Table
32
F = 0 C
140 F = 60 C
145 F = 63 C
160 F = 71 C
165 F = 74 C
170 F = 77 C
180 F = 82 C
325 F = 163 C
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These
temperatures are recommended by the U.S. Department of Agriculture
and the U.S. Food
and Drug Administration for consumer cooking. They are not intended
for processing, institutional or foodservice preparation. Foodservice
workers should consult their state or local food code, or health
department.
Never
partially cook food for finishing later because this increases the
risk of bacterial growth on the food. Bacteria are killed when foods
reach a safe internal temperature. When
preparing food in the oven, set the oven to at least 325 F.
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FOOD
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TEMPERATURE
(degrees F)
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TIPS
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| Casseroles/Combination
Dishes and Leftovers |
Casseroles/
Combination
Dishes and Leftovers |
165
F |
At
this temperature, the food will be hot and steamy throughout, a measurement
that can only be determined by a food thermometer. Thoroughly cook
meat and poultry before combining with other ingredients in casseroles
and combination dishes. |
| Eggs
and Egg Dishes |
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Eggs
(poached,
fried, scrambled and hard-cooked eggs)
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160
F *
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*
It is very difficult to insert a thermometer into these forms of
eggs and it is necessary to rely on a visual indicator. Cook so
both yolks and whites are firm, not runny.
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Egg
Dishes
(soft
stirred custard, baked custard, pumpkin pie, strata, quiche, bread
pudding, hollandaise sauce, etc.)
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160
F
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At
160 F, eggs will be thick enough to coat a metal spoon with a thin
film for soft stirred custards. For other egg dishes, such as quiche,
a knife inserted near the center should come out clean.
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Ground
Meat and Poultry
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Ground
Beef, Veal, Lamb, Pork, Bison and Game Meat
(game
meat includes deer, elk, moose, caribou, antelope and rabbits)
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160
F
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Cutting
into cooked ground meat and using color as an indicator of safety
is no longer considered reliable. Some ground meat may turn brown
before it has reached a temperature that destroys bacteria. A hamburger
cooked to 160 F, measured with a food thermometer throughout the
patty, is safe regardless of color.
Hamburger
patties are a common ground meat food. A 1/2 inch thick ground beef
patty is more likely to cook thoroughly in the middle without being
overdone on the outside than one that is too thick. A pound of beef,
before cooking, yields 4 patties measuring approximately 1/2"
by 4."
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Ground
Poultry
(turkey
and chicken)
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165
F |
Ground
poultry is cooked 5 degrees higher than ground beef, veal, lamb and
pork. |
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Hot
dogs, Luncheon Meats, Cold Cuts, Fermented and Dry Sausage, and
other Deli-Style Meat and Poultry Products
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Hot
Dogs, Luncheon Meats, Cold Cuts, Fermented and Dry Sausage, and
other Deli-Style Meat and Poultry Products
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Heat
these ready-to-eat foods until steaming hot throughout to help protect
susceptible populations from listeriosis. *
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*
People at risk for listeriosis include: pregnant women and newborns,
older adults, and people with weakened immune systems caused by
cancer treatments, AIDS, diabetes, kidney disease, etc.
Although
these foods are fully cooked, they can become contaminated with
Listeria monocytogenes. Heat these foods until they are steaming
hot throughout.
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| Large
Cuts of Beef, Veal, Lamb, Bison |
| Large
Cuts of Beef, Veal and Lamb: Roasts and Steaks |
145
F - medium rare
160
F - medium
170
F - well done
160
F - all rolled, tenderized or scored meats *
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*
CAUTION: Do not serve any rolled, tenderized or scored large cuts
of beef, veal, or lamb below 160 F. The process of cutting or puncturing
meats before cooking may force any surface bacteria into the center.
When in doubt as to how a piece of meat has been handled, cook to
160 F.
Large
cuts of beef, veal or lamb -- like roasts and steaks -- can stay
slightly pink in the center if they have reached at least 145 F.
Beef roasts cooked to 160 F will generally have very little pinkness
to the meat, and the juices will not be pink or red.
A
consumer would not be able to determine if a roast that was pink
in the center had reached 145 F without a food thermometer.
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| Pork |
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Pork
Chops and Roasts
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160
F
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Pork
chops may have just a trace of pink color at this temperature. Pork
roasts are safe when cooked to 160 F even though the center of the
roast may be somewhat pink. A consumer would not be able to determine
visually if a pork roast that was pink in the center had reached
a safe temperature.
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| Ham
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160
F - purchased "fresh" or described as "cook-before-eating"
140
F - purchased fully cooked
165
F - reheated or repackaged
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Both
vacuum-packaged fully cooked hams and canned hams can be eaten cold
just as they come from their packaging. However, if you want to
heat these fully cooked hams, set the oven no lower than 325 F and
heat to an internal temperature of 140 F.
For
fully cooked ham that has been repackaged from its original manufacturer's
packaging or for leftover fully cooked ham, heat to 165 F for greatest
safety.
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| Poultry |
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Chicken
and Turkey
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180
F - whole
180
F - thighs and wings
170
F - breasts
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Poultry
will generally reach a safe temperature (160 F) before it is "done."
At 160 F, harmful bacteria have been destroyed, but poultry will
still be pink and raw looking near the bone, and the juices will
be pink and/or cloudy. By 170 F for white meat and 180 F for dark
meat, the flesh of poultry will no longer be pink and the juices
will be clear. With whole chickens and turkeys, the joints will
move easily. This is an example of recommending a higher internal
temperature than is needed for safety to assure attaining desirable
quality aspects of "doneness."
When
cooking whole poultry, the food thermometer should be inserted into
the thickest part of the thigh (avoiding the bone).
If
cooking poultry parts, insert food thermometer into the thickest
area, avoiding the bone. The food thermometer may be inserted sideways
if necessary. When the food is irregularly shaped, the temperature
should be checked in several places
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Stuffing
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165
F - in casserole or in turkey
CAUTION:
The safest way to cook stuffing is in a casserole in a 325 F oven.
The internal temperature of the stuffing must reach 165 F.
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Today's
turkeys cook faster than in the past as they now are bred to have
a greater portion of breast meat that cooks faster than dark meat.
If you stuff your bird, you take the chance of your turkey becoming
overdone before your stuffing has reached a safe temperature.
The
ingredients for the stuffing can be prepared ahead of time. Keep
wet and dry ingredients separated; chill. Mix wet and dry ingredients
just before putting stuffing into a casserole or filling the turkey
cavity. If you choose to stuff your turkey, make sure it is stuffed
loosely. The stuffing should be moist, not dry, since heat destroys
bacteria more rapidly in a moist environment.
Cook
a turkey immediately after stuffing it. If a turkey is stuffed,
the center of the stuffing should be checked after the thigh reads
180 F. Check the temperature in the innermost part of the thigh
and in the center of the stuffing. Even if the thigh has reached
a safe internal temperature of 180 F, the center of the stuffing
inside the turkey may not have reached 165 F and can cause foodborne
illness. BOTH temperatures of 180 F for the turkey and 165 F for
the stuffing must be met.
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Duck
and Goose
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180
F - whole
180
F - thighs and wings
170
F - breast
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The
same precautions and temperatures apply as with chicken and turkey.
USDA recommends cooking whole poultry to 180 F as measured in the
thigh using a food thermometer. When cooking pieces, the breast
should reach 170 F internally. Drumsticks, thighs, and wings should
be cooked until they reach an internal temperature of 180 F.
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Seafood
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Fin
Fish
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The
FDA 2001 Food Code recommends cooking most seafood to an internal
temperature of 145 F for 15 seconds. When using the microwave, rotate
the dish several times to ensure even cooking. Follow recommended
standing times. After standing time is completed, check seafood in
several spots with a meat thermometer to be sure the product has reached
the proper temperature. |
When
you slip the point of a sharp knife into the flesh and pull aside,
the edges should be opaque and the center slightly translucent with
flakes beginning to separate. Let the fish stand three to four minutes
to finish cooking.
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Shrimp,
Lobsters and Crab
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Should
turn red and the flesh should become pearly opaque.
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Scallops
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Should
turn milky white or opaque and firm.
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Clams,
Mussels and Oysters
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Watch
for the point at which their shells open. That means they're done.
Throw out those that stay closed.
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Calibrating
a Thermometer
To assure
the accuracy of a thermometer, check and adjust if necessary by comparing
its temperature reading with the temperature of a known standard. This
process is called calibrating a thermometer.
How often
a thermometer is calibrated will depend on use. Calibrate a thermometer
whenever it is is dropped and when first purchased. If a thermometer is
used frequently, calibrate it weekly or monthly. On the other hand, if
it has been several months since it has been used, calibrate it before
use.
Some thermometers
can be calibrated by turning an adjusting nut under the head of the thermometer.
Check manufacturer's instructions. The easiest way to calibrate a thermometer
is with the ice water method.
Ice Water Method
To
use the ice water method:
-
Fill
a large glass with finely crushed ice.
-
Add
clean tap water to the top of the ice and stir well.
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Immerse
the food thermometer stem a minimum of 2 inches into the mixture,
touching neither the sides nor the bottom of the glass.
-
Wait
a minimum of 30 seconds before adjusting. TIP: For ease in handling,
the stem of the food thermometer can be placed through the clip section
of the stem sheath and, hold the the sheath horizontally, lowered
into the water.
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Without
removing the stem from the ice, hold the adjusting nut under the head
of the thermometer with a suitable tool and turn the head so
the pointer reads
32 F.
When A Thermometer
Can't Be Calibrated
Even if
a food thermometer can't be calibrated, it should still be checked for
accuracy, as described in the ice water method. Any inaccuracies can be
taken into consideration when using the food thermometer, or the food
thermometer can be replaced.
For example,
if a thermometer is checked by the ice water method and reads 34 F instead
of the recommended 32 F, it is reading 2 degrees too high. Here is one
situation of how this might apply when using a thermometer:
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Ground
beef patties must reach 160 F. If the thermometer is reading 2 degrees
too HIGH, 2 degrees would be ADDED to the desired temperature, meaning
hamburger patties must be cooked until your thermometer reads 162
F.
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Likewise,
if the thermometer were reading 2 degrees too LOW, 2 degrees would
be SUBTRACTED from the desired temperature, meaning hamburger patties
would be cooked until the thermometer reads 158 F.
For
More Information
To learn
more about using food thermometers so food is cooked safely AND so it
tastes great, check these USDA and FDA Web sites:
To call
or e-mail USDA or FDA with a temperature question:
Sometimes
it is helpful to know about how long a food needs to cook and by when
to start checking its temperature with a thermometer. The following USDA
links include charts that give a general range of minutes per pound to
cook various meat and poultry foods:
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