Hamburger Color Research
Which burgers are cooked to a safe temperature?
Answer below!
Cooked Patty Color
Foodborne illness has been associated with
Escherichia coli (E. coli) O157:H7 bacteria and inadequately cooked ground beef
patties. This has highlighted the need for a reliable indicator of thorough
cooking. Previously, consumers have been advised that the absence of pink color
can be an indicator of thorough cooking. However, the growing problem of
inconsistent cooked patty color at safe internal temperatures has caused USDA
(1997) to recommend that only thermometers be used to insure safe cooking of
beef patties.
Pink or red color in hamburgers cooked well
beyond safe temperatures (often called "hard to cook" hamburgers), is especially
a problem to food service operators. Research at the Food Technology and Safety
Laboratory has shown that the following factors may be associated with high
incidences of pink/red color when patties are cooked to a safe temperature of
160° F: (1) cooking patties frozen rather than thawed, (2) use of high pH (>6.0)
beef, (3) higher concentrations of myoglobin (red meat pigment); lower levels of
fat, (4) use of cow meat, (5) use of oat products in formulations.
Another problem that is especially important from a food safety perspective is
the presence of premature browning in cooked patties. In this situation, patties
may appear fully cooked or brown when the internal temperature may have only
reached 130-140 F. Research at the Food Technology and Safety Laboratory has
shown that the following factors may be associated with high incidences of
premature browning in cooked patties: (1) high levels of metmyoglobin (oxidized
pigment), (2) extensive or prolonged thawing of frozen patties, and (3) use of
some cereal added ingredients.
Research by the U.S.
Department of Agriculture has shown that color can be misleading. The only way
to be sure your burger is safe is to take the internal temperature with a
thermometer or temperature sensor.
 For additional information on cooked hamburger color visit USDA,
Food Safety Inspection Service
Research is continuing in our laboratory to determine processing and cooking
methods that will provide consistent and uniform internal temperatures and color
in cooked patties.
FSIS provided funding ($100K) to determine the
accuracy, reliability, and cross-contamination of temperature devices. The
information will be used by FSIS to provide guidelines to consumers for using
disposable and non-disposable temperature devices when cooking ground beef
patties and chicken breasts by different cooking method
Frequently Asked Questions
1. Where can I obtain
information on cooked patty color and are there research guidelines to assist
me?
Yes, the USDA,
Food Safety Inspection Service has
information on cooked patty color and the
American Meat Science Association has published research guidelines on a
number of subjects that are useful to meat scientists.
2. How do I measure the temperature of my hamburger
patty?
The recommended guidelines is to measure the
internal temperature. This should be done in the thickest part of the patty
using USDA recommendations with a thin, probe type, thermocouple thermometer
with a digital readout.
There are now disposable temperature sensors
that you can insert into your hamburger (or meat product) to tell you whether it
is cooked to the correct temperature.
2. Can standardized
cooking times provide uniform endpoint temperatures and color?
Not usually. Constant time cooking can still
yield wide ranges in both internal temperature and cooked color.
3. What is the safest
cooking method for hamburgers?
From recent laboratory
studies, we have found that cooking times will vary when using different cooking
methods, i.e., outdoor grilling, broiling, convection ovens, and frying with
flat griddles. So always cook your hamburger to 160º F.
4. Safe temperature rules for foods!
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