Occurrence of Pathogenic Bacterias in Raw Materials Used in Producing Ready-Made Chilli Paste and Study on Thermal-Inactivation Time

Abstract

Initial microbial loads of raw materials such as onion, garlic, dried shrimp, dried chilli and shrimp paste (kapi) that used in producing ready-made chilli paste were analysed. The results indicated that most of them contained high numbers of microorganisms. The total viable counts ranged from log₁₀ CFU/g 4.279 – 7.778. The heaviest contamination was dried chilli. Escherichia coli were found between <3-4.6 x 10² MPN/g. None of them was found to contain Salmonella spp. Staphylococcus aureus and Bacillus cereus were found ranging from log10 CFU/g 0 – 3.301 and 0 – 2.000, respectively. Clostridium perfringens was in the range of log₁₀ CFU/g 1.000-4.623 and found in all kinds of raw materials, with high count in dried chilli. After heat treatment at 80^oC for 1 hr., the microorganism count in all raw materials were lower but still present, especially C. perfringens. The survival of C. perfringens in dried chilli after holding at 80^oC for several hours were specifically investigated. The results revealed that by using the temperature at 80^oC for 8 hr., C. perfringens were completely destroyed.