Combined effects of plant and cell-free extracts of lactic acid bacteria on biogenic amines and bacterial load of fermented sardine stored at 3 ± 1 °C

Effects of cell-free extracts (CFE, 8%) prepared using Lactobacillus plantarum FI8595 or Pediococcus acidolactici ATCC 25741 alone or in combination with thyme and laurel extracts (0.5%) on physical, sensory, microbiological and chemical quality of fermented and vacuum packaged sardine fillets were investigated during 8 wk of chilled storage (3 ± 1 °C). Sardine fillets were divided into 7 groups with the control being untreated. The other groups were treated with CFE of Lb. plantarum (LP group) and P. acidolactici (PA group). In addition, thyme with LP CFE (THLP) or PA CFE (THPA); and laurel with LP CFE (LALP) or PA CFE (LAPA) were also prepared. According to the sensory and physical assessment, shelf life of fermented fish was 5 wk for the control, 6 wk for LP, PA, LALP and LAPA, and 7 wk for THPA and THLP, although chemical and microbiological results exhibited longer shelf life. THPA and THLP had the lowest bacterial growth and TBA values. TVB-N values remained below 35 mg/100 g until 7 wk for all groups. THPA significantly reduced TMA formation. The study suggested that cell-free extracts of Lb. plantarum and P. acidolactici with thyme extract was the most effective way to improve the shelf-life of fermented sardines stored at chilled temperature.