Effective in vitro evaluation of biogenic amines in fermented food using mast cells

Legal limits and toxic thresholds for histamine levels in food have been established by the Codex Alimentarius Commission as well as by national food safety authorities in various countries In this study, we found that mast cell degranulation was increased in a histamine concentration-dependent manner, and this degranulation was found to be associated with MRGPRX2, a receptor involved in non-IgE-mediated allergic reactions, as demonstrated by molecular docking analysis and mRNA expression. A strong positive correlation was observed between MRGPRX2 and mast cell degranulation, indicating that higher MRGPRX2 mRNA levels were associated with increased degranulation activity. We analyzed histamine concentrations, MRGPRX2 mRNA expression, and mast cell degranulation for fermented soy sauce and shrimp sauce (FSS, used as a positive control). DS, FS, and JS demonstrated a histamine concentration below 200 μg/mL and showed no significant effect on mast cell degranulation and MRGPRX2 mRNA levels in HMC-1.2 cells. Especially, FS contained high GABA concentrations. A strong negative correlation and the expression of MRGPRX2 mRNA as well as mast cell degranulation. Finally, this assay, anchored to the histamine limits recommended by the Codex, enables routine screening of biogenic amine-containing foods to verify regulatory compliance and help ensure a safe food supply.