Process Optimization and Quality Assessment of Nem, a Traditional Cambodian Lactic Acid Fermented Fish Product

Author(s): Liseany Chor, Sengly Sroy, Chanthol Peng, Seyha Doeurn

Cambodia has a long-standing tradition of processing freshwater fish, and fermented foods, particularly Nem, hold significant importance among all fishery products in Cambodia. However, the traditional production methods of these fermented fish products, based on generational knowledge, pose challenges in establishing standardized quality indices and optimal production methods. This study aimed to address these challenges by conducting a survey questionnaire on local Nem production, raw materials, and finished products. Through the survey results with Nem producers and a comprehensive literature review, an acceptable standardized method was documented. The study also included a quality assessment involving physicochemical, nutritional, and microbiological analyses to evaluate the safety and overall quality index of Nem produced in laboratory. Shelflife analysis was conducted over a two-week period. The raw fish used in Nem production exhibited the following quality attributes: pH 6.76, acidity 0.37%, water activity 0.99%, moisture content 79.25%, ash content 2.29%, total fat 0.25%, and total protein 18.19%. During fermentation, the pH, acidity, and water activity ranged between 4.54-4.47, 0.81%-0.77%, and 0.97% respectively. The counts of viable bacteria count (VBC), lactic acid bacteria (LAB), and total yeast and molds (TYM) at the end of the 12-day storage period ranged from 8.08 Log CFU/g to 8.11 Log CFU/g and 8.74 Log CFU/g, respectively. These results indicate that Nem maintained high-quality parameters during the fermentation period and met acceptable standards for consumption due to its high protein content. Furthermore, after 12 days of storage at 4°C, Nem demonstrated good quality in physicochemical, nutritional, and microbiological analyses