Abstract:

The effect and underlying mechanism of 60Co-γ irradiation on sterilization, sensory quality, and physiological
and biochemical indices of ‘Fenggan’ chestnut namely raw ready-to-eat chestnut was examined and the optimal dose of
irradiation to extend shelf life was determined. Total bacterial count, mold and yeast, coliform bacteria, and pathogenic
bacteria (Salmonella), some sensory attributes and physical and chemical indicators of ‘Fenggan’ chestnut irradiated with
different doses of 60Co-γ were measured after 0, 10, 15, 20 and 30 days of storage. Results showed that the total count of
bacteria in 60Co-γ treated ‘Fenggan’ chestnut was much lower than that in the untreated one, and irradiation doses in the
range of 3.5–5.0 kGy were able to cause a good bactericidal effect on ‘Fenggan’ chestnut, especially 4.0 kGy dose. Together
sensory quality evaluation and physiological and biochemical analyses indicated that exposure dose of 4.0 kGy could not
only effectively inactivate microorganisms and prolong the shelf life of ‘Fenggan’ chestnut, but also could improve sensory
quality and maintain physiological and biochemical quality during its shelf life. This preliminary study indicated that the
irradiation dose of 4.0 kGy can extend the shelf life by at least 20 d at 4 ℃ in terms of microbial safety limits.

Key words: irradiation, ‘Fenggan&rsquo, chestnut, sterilization, sensory quality