ScienceAsia 4 (1978): 073-078 |doi: 10.2306/scienceasia1513-1874.1978.04.073
CHANGES IN THE VIABLE BACTERIAL POPULATION, pH, AND CHLORIDE
CONCENTRATION DURING THE FIRST MONTH OF NAM PLA (FISH SAUCE) FERMENTATION
CHAUFAH THONGTHAI and MALINEE SIRIWONGPAIRAT
Summary: Traditionally fermented Nam Pla contained 6.5 x 104 viable haloduric bacteria
per ml on the first day of fermentation. The organisms died steadily and reached 100 per ml after 11 days of fermentation. Halophilic bacteria which required 20 % NaCI for growth were not detectable at the start of fermentation but gradually ap.
peared and increased to 9.5 x 105 per ml after 14 days of fermentation. The chloride concentration and pH of one day old Nam Pla were respectively 33.1 % and 5.5. There was little change in the pH of fermenting Nam Pla. However, the chloride concentration decreased as much as 5 % after four days of fermentation. This study showed that growth of halophilic bacteria was associated with the decrease in chloride concen. tration during Nam Pla fermentation. The roles of salinity and halophilic bacteria in the traditional fermentation of Nam Pla are discussed.
Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, Thailand
Received 8 May 1978