BIOGENIC-AMINE FORMATION IN FRESH VACUUM-PACKAGED BEEF STORED AT -2-DEGREES-C AND 2-DEGREES-C FOR 100 DAYS

When fresh, vacuum-packaged, meat products are stored for extended periods of time, undesirable changes, due to naturally occurring microbial flora present during packaging occur. Lactobacillus spp. are known to form amines through the decarboxylation of free amino acids. Tyramine and histamine can cause intoxication in individuals taking monoamine oxidase-inhibiting drugs. This study determined 1) the effect of storage temperature on bacterial growth and biogenic amine production in vacuum-packaged beef subprimals, 2) the effect of washing subprimals with water to remove tyramine contamination, and 3) the penetration of tyramine from the surface of the subprimal. Inside rounds were vacuum packaged and stored at -2-degrees-C or 2-degrees-C. Samples were evaluated over 100 days for amine concentrations, total psychrotrophic counts and lactic acid bacteria. Tyramine, putrescine and cadaverine were detected in this study. Significant levels (15 mug/g) of tyramine were detected at 20 days of storage at 2-degrees-C and 40 days of storage at -2-degrees-C. Putrescine and cadaverine were detected first at 40 days of storage at 2-degrees-C and 60 days of storage at -2-degrees-C. Both treatment groups contained about 130 mug/g of tyramine at 100 days of storage. Psychrotrophic plate counts and lactic acid bacteria counts were initially 10(3) colony forming units (CFU)/cm2 and ranged from 10(6)-10(7) CFU/cm2 at 100 days of storage. Even though tyramine was evident at a depth of 6 mm from the surface of the cut, one-third of the amine was removed by washing the subprimal with tap water.