BIOGENIC-AMINE FORMATION IN FRESH VACUUM-PACKAGED BEEF DURING STORAGEAT 1-DEGREES-C FOR 120 DAYS

Undesirable changes in vacuum-packaged beef products during prolonged storage can present a problem to some consumers. Bacterial proteolysis and decarboxylation can release pressor amines, such as tyramine and histamine, that can be toxic when ingested by individuals taking monoa mine oxidase-inhibiting drugs. This study determined the effect of car cass decontamination on bacterial growth and biogenic amine production in vacuum-packaged subprimals. Beef carcasses were treated with 200 p pm chlorine or 3% lactic acid sprays, fabricated, vacuum packaged, and stored at 1-degrees-C. Samples were evaluated up to 120 d for amine c oncentrations, total aerobic counts, and lactic acid bacteria. Of all the amines monitored, only tyramine was consistently detected over the course of the study. Significant levels of tyramine were detected sta rting at day 20 of storage in all treatments and controls. By day 60, the levels had increased to about 50 mug/g and continued to increase t o about 180 mug/g by 120 d of storage. Tryptamine was detected in some samples by 60 d of storage, but the levels were variable and did not follow any trend. Initial aerobic plate counts ranged from 10-200 CFU/ cm2, whereas lactic acid bacteria counts were from 6-46 CFU/cm2. Bacte rial numbers increased exponentially until about day 60, when they lev eled off at between 10(6)-10(7) CFU/cm2, with no differences between a ny of the treatments and/or controls. Although the vacuum-packaged bee f was organoleptically acceptable up to day 60 (day 90 for some sample s), it could pose some fisk to individuals sensitive to biogenic amine s if the product is stored at 1-degrees-C or higher for 60 d or more.