Inoculation packed studies on the shelf-stable food products: 1. Effects of gamma irradiation at 45 kGy on the survival of Clostridium sporogenes spores in the foods (Preliminary results)

Inoculation packed studies on Indonesian shelf-stable food products using Clostridium sporogenes spores strain CVL 1658/BCC 207 were carried out. The freeze dried bacterial spores were first grown in Robertson's Cooked anaerobic medium (RCMM), and checked for purity on 5% sheep blood agar plate prior to its use.. Multiplication of the spores was done using Duncan and Strong's sporulation medium. Different type of Indonesian shelf-stable food dishes were inoculated with varying levels of Clostridium sporogenes spores, irradiated with a minimum dose of 45 kGy under cryogenic condition, and stored for 7 days at room temperature. Control, inoculated, and inoculated-irradiated samples were microbiologically examined using different parameters. Calculation of viable spore numbers per-ml suspension was done by most probable number (MPN) while microbial count, isolation and identification of Clostridium sporogenes were conducted according to Australian Standard Method. Results showed that a dose of 45 kGy is very effective in eliminating Clostridium sporogenes spores inoculated in all food samples. (author)