.8. Bacterial count, histamine-degrading capability, and histamine dehydrogenase activity assay
The bacterial count was determined by plate count assay. The cultured histamine broths were serially diluted with a sterile phosphate buffer (1:9), and 1.0-mL aliquots of the cultured histamine broth, or dilutes were poured onto Petri dishes (9 cm in diameter). Then, 15–20 mL of TSA (Difco) containing 0.5% NaCl at 45–50°C was added and gently mixed. The poured plates were allowed solidify under a biological clean bench. Bacterial colonies were counted after the plates were incubated at 30°C for 48 hours, and bacterial numbers were expressed as log10 CFU/g.