Appearance Identification
Fresh pork has a slightly dry outer surface, is light red in color, and has a luster. The cut surface is slightly moist, not sticky, and the meat juice is transparent.
Sub-fresh pork has a dark gray surface without luster. The color of the cut surface is slightly inferior to fresh pork, it is sticky, and the meat juice is turbid.
The incision line of a diseased pig is smooth without blood infiltration; the incision of a healthy pig is rough, the surface is turned outwards, and there is a blood infiltration zone around the incision reaching 0.5 to 1 cm deep.
The fat of a diseased pig is pink; that of a healthy pig is white or off-white. The cut surface of diseased pork is dark purple, and the flat cut surface has pale yellow or pink liquid; the cut surface of healthy pork is lustrous, brown or pink, with no liquid flowing out.
The lymph nodes of a diseased pig are enlarged or atrophied and appear grayish-purple; those of a healthy pig are pink. Due to incomplete bleeding in a diseased pig, residual blood outside the vessels is purplish-red and may contain bubbles; in a healthy pig, bleeding is good with very little residual blood in the vessels.
Odor Identification
Fresh pork has a normal odor; sub-fresh pork may have a slight ammonia, sour, or sour-musty smell on the surface, but these odors are not present deep within the meat.
Elasticity Identification
When pressed with a finger, fresh pork will rebound immediately, and the meat surface feels non-sticky.
For spoiled pork, the depression made by pressing does not rebound, and sometimes the finger can pierce the meat. It has a distinctly sticky feel to the touch.