The New Complete Book of Food
naturally in pork are the small amounts of glycogen in its muscles, we add sugars in the
form of marinades or basting liquids that may also contain acids (vinegar, lemon juice, wine)
to break down muscle fibers and tenderize the meat. Browning has one minor nutritional
drawback. It breaks amino acids on the surface of the meat into smaller compounds that are
no longer useful proteins.
When pork is heated, it loses water and shrinks. Its pigments, which combine with
oxygen, are denatured (broken into smaller fragments) by the heat and turn brown, the natu-
ral color of cooked meat. This color change is more dramatic in beef (which starts out red)
than in pork (which starts out gray pink). In fact, you can pretty much judge beef’s doneness
from its color, but you must use a meat thermometer to measure the internal temperature of
the meat before you can say it is thoroughly cooked.
Pork is considered done (and safe to eat) when it reaches an average uniform internal tem-
perature of 170°F, hot enough to kill Trichinella spiralis, the organism that causes trichinosis.*
Killing these organisms is one obvious benefit of heating pork thoroughly. Another is
that heat liquifies the fat on the meat so that it simply runs off the meat. The unsaturated
fatty acids that remain in the meat, continue to oxidize as the meat cooks. Oxidized fats give
cooked meat a characteristic warmed-over flavor. You can reduce the warmed-over flavor
by cooking and storing the meat under a blanket of catsup or a gravy made from tomatoes,
peppers, and other vitamin C–rich vegetables, all natural antioxidants that slow the oxida-
tion of the fats.How Other Kinds of Processing Affect This Food
Freezing. Freezing changes the flavor and texture of fresh pork. When fresh pork is frozen,
the water in its cells turn into ice crystals that can tear the cell walls so that liquids leak out
when the pork is thawed. That’s why defrosted pork, like defrosted beef, veal, or lamb, may
be drier and less tender than fresh meat.
Curing, smoking, and aging. Curing preserves meat by osmotic action. The dry salt or a salt
solution draws liquid out the cells of the meat and the cells of any microorganisms living
on the meat. Smoking—hanging meat over an open fire—gives meat a rich, “smoky” flavor* Cooking pork in a microwave oven requires careful attention to the temperature. In 1982, researchers
at Iowa State University found live trichinae in nine of 51 experimentally infected samples of pork that
had been cooked in different brands and models of microwave ovens according to directions from the
manufacturers and from the Pork Producers Council. In each case, while the internal temperature of
the meat rose to 170°F, moisture evaporating on the surface of the meat kept the temperature there too
low to kill the trichinae. In a second study, in 1983, the researchers recommended that pork cooked in
a microwave oven be cooked in a special transparent plastic cooking bag to prevent the evaporation of
moisture on the surface of the meat. Subsequent laboratory tests at Iowa showed that pork roasts micro-
waved in these bags reached temperatures high enough to kill trichinae on all surfaces of the meat.
Osmosis is the physical phenomenon by which liquids flow across a membrane, like a cell wall, from a
less dense to a more dense environment. Since salt or salty liquid is denser than the liquid inside cells,
it pulls out moisture. Pork becomes dryer, and the microorganisms, which cannot live without water,
died after preparing the meat. Irradiation destroys the thiamin (vitamin B 1 ) in fresh pork.