pH decreased to 5.3when the sausage
was left to ferment by the indigenous flora alone, whereas it was
reduced to 4.5–4.7 in 48 h when inoculated with P. acidilactici. The
spontaneous fermentation was unable to prevent growth of
B. megaterium, C. perfringens and V. parahaemolyticus whereas addition
of P. acidilactici eliminated growth of V. parahaemolyticus, C. perfringens
and B. cereus and reducedmaximumcell density of the other pathogenic
strains to 102–104 CFU/g. Similar results have been obtained for Thai
fermented pork sausage, nham, which has a composition close to somfak,
except that minced pork is used instead of minced fish (Petchsing
and Woodburn, 1990).