Effect of gamma-irradiation upon biogenic amine formation in blue cheese during storage

The evolution in biogenic amine content of 12-day old Blue cheese, was monitored throughout storage at 5 degrees C, either non-irradiated or gamma-irradiated at 2, 4 or 6 kGy. On a dry weight (DW) basis, the total content of biogenic amines increased from 1023.4 to 2310.2 mg kg(DW)(-1) in non-irradiated cheeses within 90 d, but decreased from 976.7 to 431.5 mg kg(DW)(-1) after irradiation at 6 kGy. Tyramine was dominant; it accounted for 96.1% of the total in non-irradiated cheeses, and 92.8-94.3% in their irradiated counterparts by 90 d of storage. From 35.7 mg kg(DW)(-1) in 90 d non-irradiated cheese, histamine decreased to 29.0 mg kg(DW)(-1) following irradiation at 2 kGy, and was not detected at 4-6 kGy. In sensory terms, irradiated cheeses were fully comparable with non-irradiated ones, except at the highest level of irradiation and longest storage times. Irradiation thus proved effective and useful in controlling biogenic amine levels in Blue cheese during storage.