Prevalence and characterization of Vibrio vulnificus isolated from shrimp products imported into Denmark

Vibrio vulnificus is a naturally occurring bacterium in tropical aquatic environments. We investigated the prevalence of V. vulnificus in frozen shrimp products mainly originating from tropical countries by pre-enrichment of samples in alkaline peptone water supplemented with polymyxin B (APWP) followed by subculture onto modified cellobiose-polymyxin B-colistin (mCPC) agar. V. vulnificus was detected in 3 of 46 (7%) frozen raw shrimp samples analyzed. However, V. vulnificus was not recovered from any of the 61 frozen cooked products, suggesting that these products were adequately heat treated and that cross-contamination did not occur during processing. The pre-enrichment of shrimp samples in APWP followed by subculture on mCPC agar proved useful for the isolation of V. vulnificus. The absence of V. vulnificus in frozen cooked shrimp products and the low prevalence of V. vulnificus in frozen raw shrimp suggest that V. vulnificus in imported shrimp products does not constitute a potential hazard to public health.