The effect of low-dose gamma irradiation and temperature on the microbiological and chemical changes during ripening of Cheddar cheese

The effect of 4 kGy ionisation irradiation, combined with ripening temperatures at 8°C and 16°C on the ripening of Cheddar cheese was investigated. Changes in cheeses were monitored by sensory, microbiological, and chemical analyses.

The sensory analysis showed that no cheese was preferred above the other. At 16°C ripening, irradiation affected most bacterial groups, but not the psychrotrophs. The free fatty acid content of the cheeses was not affected by irradiation, but higher thiobarbituric acid-values were observed after ripening at 16°C, as well as a higher water-soluble nitrogen to total nitrogen ratio. Differences in proteolysis products were detected by urea-page and RP-HPLC.

Reference:

Seisa, D, Osthoff, G., Hugo, C., Hugo, A., Bothma, C. & van der Merwe, J., 2004. The effect of low-dose gamma irradiation and temperature on the microbiological and chemical changes during ripening of Cheddar cheese. Radiation Physics & Chemistry 69, 419-431.