Comparison of effects of Wasabia japonica and allyl isothiocyanate on the growth of four strains of Vibrio parahaemolyticus in lean and fatty tuna meat suspensions

Lean tuna meat suspensions (LEAN), with a fat content of 0.006%, and fatty tuna meat suspension (FATTY), with a fat content of 3.0% were inoculated with four strains of Vibrio parahaemolyticus and wasabi (Wasabia japonica Matsumura) or allyl isothiocyanate (AIT) was added before incubation at 37°C. During the incubation, viable Vibrio counts were determined on TCBS agar plates. Both LEAN and FATTY suspensions were inoculated with V. parahaemolyticus AOTO-81, (1.28±0.20)×102 CFU/ml, followed by addition of 20 mg wasabi/ml, and incubation for 8 h. The viable Vibrio counts were (7.76±5.93)×105 CFU/ml in LEAN and (3.50±2.65)×101 CFU/ml in FATTY. When the same strain, at (1.18±0.22)×102 CFU/ml, was incubated for 8 h with 50.9 μg AIT/ml, viable Vibrio counts were (4.79±1.78)×104 CFU/ml in LEAN and (1.80±1.30)×101 CFU/ml in FATTY. Growth of the other three strains with wasabi or AIT was shown to be less in FATTY than in LEAN. These results indicate that growth of V. parahaemolyticus is inhibited more in FATTY than in LEAN by wasabi and allyl isothiocyanate.