2023 Volume 14 Issue 2 Pages 7-13
Prahok (fermented fish paste) is commonly used as a side dish or condiment in Cambodian cuisine. Because of the condition of the raw material and inadequate hygiene during processing, this type of fermented fish is frequently loaded with histamine toxicity. The purpose of this study was to examine the potential histamine-producing bacteria (HPB) isolated from prahok collected from three provinces in Cambodia and to evaluate the efficacy of local lactic acid bacteria (LAB) in controlling those HPB. For HPB isolation, a modified Niven's agar was used and the bacteria species were identified using the Biolog GEN III Semi-automatic system, while histamine concentration was quantified using a colorimetric enzyme assay. Ten LAB strains from the stock collection of Laboratory Food Biotechnology, Faculty of Agro-Industry, were used to evaluate their antibacterial activities against HPB using the well diffusion method and the co-culture method, and compared to the control which involved growing HPB without LAB. As a result, five identified HPBs isolated from prahok, including Enterobacter aerogenes, Klebsiella oxytoca, Morganella morganii, Proteus penneri, and Staphylococcus xylosus, were found to produce histamine at levels of more than 200 ppm in vitro. A well diffusion and co-culture examination demonstrated that the growth of all potential HPB cultured with three LABs (Lactobacillus plantarum, Lactobacillus gasseri, and Lactococcus lactis) of a total of 10 LAB strains was inhibited compared to the control. In conclusion, because the three LABs listed above cannot create histamine, they are promising candidate LABs to apply in Prahok processing to control HPB as well as histamine levels in the final product.
