| Q |
What is dark-cutting or dark, firm, and dry (DFD)
beef? |
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| A |
Dark-cutting or dark,
firm, and dry (DFD) beef occurs when animals are subjected to pre-slaughter
stress resulting in depletion of muscle glycogen levels. Reduced levels of
muscle glycogen eventually result in a high muscle pH. High muscle pH leads to
a characteristic dark color and a dry or sticky texture on the surface of the
meat. Consequentially, consumers are unwilling to purchase meat with this
condition. Also, dark cutting beef may be more susceptible to off-flavors and
the shelf life of the product may be compromised since the high pH does not
inhibit bacterial growth and spoilage occurs more rapidly. |
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For more information on dark-cutting beef see the following links… |
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http://www.grandin.com/references/dark.cutters.html |
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http://www.agric.nsw.gov.au/reader/$WEB%20HOME?MIval=link&name=dai244.htm |
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http://www.feedlotsolutionsonline.com/Dark%20Cutting%20Beef.PDF |
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http://www.avs.uidaho.edu/sduckett/darkc.html |
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| Q |
What is aging? |
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| A |
Aging can be defined as the holding of carcasses
or meat at refrigeration temperatures. Aging periods can range considerably in length from as short as 2 days to as long as 90 days for some “white table
cloth” restaurants. The principle action of aging is an improvement in
tenderness as a result of enzymatic degradation of certain muscle proteins.
Improvements in beef flavor may also occur. Aging of carcasses and uncovered
wholesale cuts in a cooler is referred to as "dry" aging. Aging also occurs as
beef is packaged into vacuum packages (bags) and placed into a box for shipping
from the point of slaughter until meat is needed for display and sale at the
retail level. This is referred to as “wet” aging” or "aging in the bag." |
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For more information on aging of beef see the following links… |
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http://www.extension.umn.edu/distribution/nutrition/DJ5968.html |
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http://muextension.missouri.edu/explore/agguides/ansci/g02209.htm |
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| Q |
What are beef quality and yield grades?
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| A |
Beef quality grades are designed to segregate
carcasses based on expected palatability (tenderness, juiciness, and flavor).
Principle factors in determining beef quality grades are maturity and marbling.
Young beef qualify for Prime, Choice, Select, and Standard quality grades, while
Commercial, Utility, Cutter, and Canner quality grades are reserved for more
physiologically mature beef carcasses. Yield grade refers to the amount of
boneless closely trimmed retail cuts expected from the major wholesale cuts of
beef carcasses. Beef yield grades range from 1 to 5, with yield grade 1 being
more desirable in relation to the amount of lean meat yield. Factors used to
determine yield grades in beef are fat thickness, ribeye area, kidney, pelvic,
and heart fat, and carcass weight. Grading of beef carcasses is voluntary and
conducted by the Agriculture Marketing Service of the USDA. |
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For more information on beef grading see the following links… |
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http://animalscience-extension.tamu.edu/publications/13302381-beefgrading.pdf |
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http://www.ianr.unl.edu/pubs/beef/rp357.htm#qg |
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http://www.ansi.okstate.edu/exten/general/f-3972.pdf |
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http://meat.tamu.edu/beefgrading.html |
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http://www.gabeef.org/gbb/preparation/quality.htm |
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http://www.caf.wvu.edu/~Forage/yieldgrd/yieldgrades.htm |
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http://www.wvu.edu/~agexten/pubnwsltr/TRIM/10202.htm |
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|
| Q |
Why does beef appear dark (purplish) colored
when it is vacuum packaged? |
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| A |
Beef that is vacuum-packaged appears a dark,
purplish-color because it is not exposed to oxygen. When the package is opened
and the product is exposed to air for a few minutes, the beef will turn a bright, cherry-red color.
This also explains why the center of a package of fresh ground beef typically is
darker than the outside, which has been exposed to oxygen. |
| |
|
| Q |
Why does some beef have an iridescent
(rainbow-like) sheen? |
| |
|
| A |
Sliced cooked beef or lunchmeat and some
fresh whole muscle beef cuts can have an iridescent color. Iridescence is
caused when light reflects off of the various compounds inherently present in
meat. Iridescence is a natural phenomenon and is not associated with meat
spoilage. Spoiled beef could have similar colors, but would also probably be
slimy or sticky and have an off-odor. |
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|
| Q |
Why does some beef turn brown after a few
days of refrigeration? |
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|
| A |
After beef has been refrigerated for a few days,
it may turn brown due to chemical changes in myoglobin, the protein responsible
for the color of meat. Beef that has turned brown during extended storage may
have an off-odor, and be tacky to the touch. Sometimes, ground beef may appear
red on the outside of a package and dull, grayish-brown on the inside of the
package. The grayish-brown color is due to a lack of oxygen and is not
associated with spoilage; however, if all the meat in the package has turned
grayish-brown, it may be beginning to spoil. |
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| Q |
What is Modified Atmosphere Packaging (MAP)?
|
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| A |
Modified Atmosphere Packaging (MAP) involves
removing the air from a food package by vacuum and introducing a gas into the
package in order to prolong the shelf life of the product it contains. The
introduced gas may be nitrogen, carbon dioxide, or other gases. |
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| Q |
What is irradiation?
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| A |
 Irradiation is food safety technology that can
eliminate disease-causing organisms in food products, including beef. The
nutritional profile of foods is not altered as a result of the irradiation
process. Furthermore, the process of irradiation itself does not render the
food dangerous in any way. |
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For more
information on irradiation see the following link… |
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http://www.ces.ncsu.edu/depts/foodsci/agentinfo/hot/irradiation.html |
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| Q |
What is HACCP?
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| A |
HACCP stands for Hazard Analysis and Critical
Control Points. HACCP is a preventative food safety system, first developed for
astronauts in space. HACCP includes seven basic principles: hazard analysis,
critical control point identification, establishing critical limits, monitoring
procedures, corrective actions, verification procedures, and record-keeping. |
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For more information on HACCP see the following links… |
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http://vm.cfsan.fda.gov/~lrd/haccp.html |
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http://www.haccpalliance.org/ |
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| Q |
What are some common foodborne
illness-causing bacteria that may be present in beef? |
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| A |
Some of the common foodborne illness-causing
bacteria that may be present in beef include Campylobacter jejuni,
Clostridium perfringens, various Escherichia coli, Listeria
monocytogenes, Salmonella, Staphylococcus aureus, and Streptococcus. |
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For more information on food safety in beef see the following links… |
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http://www.foodsafety.gov/~fsg/fsgpath.html |
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http://www.ces.ncsu.edu/depts/foodsci/agentinfo/hot/fbi.html |
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| Q |
Why is ground beef more of a concern in
regards to food safety than whole muscle cuts such as roast or steaks? |
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| A |
For answers to this question or for more
information on food safety and ground beef see the following link: |
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http://www.ces.ncsu.edu/depts/foodsci/agentinfo/meat/conspub.html#nutrition |
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| Q |
What is mad cow disease or BSE?
|
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| A |
“Mad Cow Disease”
or Bovine spongiform encephalopathy (BSE) is a chronic, degenerative disorder
affecting the central nervous system of cattle.
Several countries are affected with BSE. However, to date, BSE has never been
diagnosed in North America.
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For more information on BSE see the following link… |
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http://www.ces.ncsu.edu/depts/foodsci/agentinfo/hot/BSE.html |
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| Q |
What is country-of-origin labeling (COOL)?
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| |
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| A |
Country-of-origin labeling was
passed as part of the 2002 Farm Bill and will require certain commodities,
including beef products, to be labeled according to the country from which the
product originated.
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For more information on
COOL see the following links… |
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http://www.ams.usda.gov/cool/ |
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http://www.fsis.usda.gov/OA/congress/cool.htm
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