Use of γ-aminobutyric acid producing lactic acid bacteria as starters to reduce biogenic amines and cholesterol in Thai fermented pork sausage (Nham) and their distribution during fermentation

• A mixed probiotic of Lactobacillus namurensis NH2 and Pediococcus pentosaceus HN8 was dominant in Nham.
• Inoculated Nham reduced 7 biogenic amines to meet the safety regulation requirements.
• Inoculated Nham with monosodium glutamate, 5 g/kg had 3962 mg/kg γ-aminobutyric acid.
• Cholesterol content in GABA Nham was much lower than that in commercial Nham brands.
• A novel fermented pork sausage (Nham) that is safe and healthier has been developed.

The objectives of this study were to reduce the amounts of biogenic amines (BAs) and cholesterol in Thai fermented pork sausage (Nham) using the γ-aminobutyric acid (GABA) producers, Pediococcus pentosaceus HN8 and Lactobacillus namurensis NH2, as a mixed starter (6 log CFU/g for each strain). The distribution of lactic acid bacteria (LAB) was also monitored to follow the prevalence of the mixed starter during fermentations. The starter cultures in the inoculated Nham sets (TSM, starter + 5 g/kg monosodium glutamate, MSG; and TSN, starter + no MSG) reduced the amounts of 7 BAs to meet the safety regulation requirements in the order of β-phenylethylamine > histamine > tyramine > putrescine > spermine > spermidine > cadaverine. In contrast, with the control fermentations (TNN, no starter + no MSG and TNM, no starter + MSG, 5 g/kg) only histamine was higher than the recommended level. Cholesterol content was also reduced by 35% in the GABA Nham set (TSM, GABA 3962 mg/kg) when compared with the TNN; and this was significantly lower than the popular commercial Nham brands (114–125 mg cholesterol/100 g). Determination of the LAB succession confirmed that the starter cultures played the biggest roles in reducing both the BAs and cholesterol levels.