Occurrence and Virulence Characteristics of <scp><i>A</i></scp><i>eromonas</i> Species in Meat, Milk and Fish in <scp>I</scp>ndia

Abstract

Abstract A eromonas ‐induced gastroenteritis is common in I ndia. The incidence of A eromonas in meat, milk and fish in K olkata, I ndia and their enterotoxic potentiality have been evaluated here. A eromonas contamination was detected in all or most of the meat and fish with average load of 1.1 × 10 2 , 3.5 × 10 3 , 1.1 × 10 3 , 2.1 × 10 3 and 1.6 × 10 4 cfu/g of red meats, chicken, I ndian major carps, tilapia and shrimp, respectively; the levels were at least one order higher on fish skin and meat surface. A eromona s was also detected in milk and ready‐to‐eat foods. About 59% of the isolates were β‐hemolytic, and 66–92% of them produced phospholipase, caseinase and enterotoxicity. Fish and shrimp isolates produced significantly higher levels of gelatinase (102.73–120.6 U/ mL ), hemolysin (causing &gt;80% erythrocyte lysis) and enteric fluid accumulation (0.86–0.89 mL /cm ileum length) compared with those from meat and milk indicating their serious pathogenic potentiality. Phenotypically, 43.2, 12.2 and 12.2% of β‐hemolytic strains were identified as recognized human pathogenic species, viz. A eromonas hydrophila , A eromonas caviae and A eromonas veronii bv. sobria, respectively, which also expressed higher levels of virulence factors than other A eromonas species detected. The ubiquitous presence of enterotoxigenic A eromonas in different raw as well as ready‐to‐eat foods poses serious threat to human health. Practical Applications Ubiquitous presence of enterotoxigenic A eromonas hydrophila , A eromonas caviae and A eromonas veronii bv. sobria in raw and ready‐to‐eat meat, milk and fish poses a serious human health risk in Indian subcontinent. Heavy bacterial load, combined with higher expression of virulence factors by the isolates, makes fish and shellfish as the most potential sources of A eromonas infection. Different A eromonas spp. differed in quantitative expression of different virulence factors. Qualitative and quantitative expression studies showed low positive correlations among gelatinase, hemolysin and ileal enterotoxicity, suggesting requirement of studying multiple virulence factors for identifying the virulent strains. A higher distribution of the bacterium on meat or fish surface and in unhygienically processed or stored food items indicates that adoption of standard practices of cleaning and sanitation would substantially improve safety of food products.