Hygiene evaluation of meat. Taking of the meat samples. Laboratory tests.
Hygiene evaluation of meat
-sample should be weighed around 200g, immediately to the laboratory, NOT older than 48h, careful documentation (kind of meat, quantity, date, time, goal of investigation)
-samples are taken usually from the surface and the inferior of the meat
Laboratory tests
-organoleptic: should be firm and elastic, not either pink nor deep purple, agreeable odor, should not be slimy
-meat bouillon reaction with copper sulfate: small pieces of meat (20g) boiled 5 minutes in distillated water, to proof presence of water soluble proteins (no changes/no precipitates → negative reaction; floccules/bouillon jellies with green-blue color → positive reaction)
-test for peroxidase: meat extract is tested for the presence of the enzyme peroxidase (adding alcohol benzidine solution); if present → blue-green color compounds are formed → ONLY fresh meat contains peroxidase activity (it breaks down the oxygen)
-reaction for ammonia: meat extract is tested for the presence of ammonia (adding Nesslers reagent solution); negative result → no color change; positive reaction → color change to yellow/green
-microbiological analysis: using direct microbial indices (standard colony count, test for pathogenic microorganisms→coli test, staphylococci, salmonella)
-parasitology investigation: tape worms → taenia solium, taenia saginata, trichinella spiralis → trichinella spiralis: humans become infected when they consume improperly cooked pork or trichinella infected meat (can be seen with microscopic examination) →prevention: cook over 74°C