Effects of gamma irradiation on the biogenic amines in pepperoni with different packaging conditions

Combined effects of gamma irradiation and packaging on biogenic amine (BA) formation in pepperoni sausage were investigated during storage. Pepperoni (fermented sausage) was made and packaged with air, vacuum and CO ₂/N₂ (25%/75%) gas and then gamma-irradiated at 0, 5, 10 and 20 kGy. The pH was decreased after storage and non-irradiated samples showed a lower pH than irradiated. Lactic acid bacteria (LAB) were not detected after 5 kGy of gamma irradiation, while the LAB in the non-irradiated samples were 4-5 log counts during storage. A total of six different BAs, putrescine, cadaverine, β-phenylethylamine, spermidine, spermine and tyramine, were found in the pepperoni sausage. Detected BAs were statistically low under the irradiation or packaging conditions, except for cadaverine and β-phenylethylamine. Gamma irradiation was effective in reducing putrescine, spermidine, spermine and tyramine. Irradiation effects were not observed on the β-phenylethylamine level, while the CO₂/N₂ packaging caused increasing of the level. Most BAs detected were reduced by gamma irradiation of the pepperoni sausage during storage. However, CO ₂/N₂ packaging was an improper condition for BA reduction in the pepperoni sausage.