Growth and enterotoxin production ofStaphylococcus aureusin shrimp

Abstract

SUMMARYStrains ofStaphylococcus aureusisolated from shrimp were examined for phage pattern and enterotoxin production; 63% of the strains isolated from North Sea shrimp were typable with the International and additional set of phages, as were 38% of the strains isolated from South-East Asian shrimp. Staphylococcal enterotoxin(s) (SE) were produced by 48% and 35% of strains isolated from North Sea and South-East Asian shrimp respectively. Growth and enterotoxin production byS. aureusin shrimp was examined in storage experiments at 22 °C.S. aureusincreased by 1–2 log units in 24 h when the organism was only a minor part of the total microflora of shrimp. WhenS. aureuswas an equivalent part of the total flora its numbers increased by 3–4 log units in 24 h. Enterotoxins A and B became detectable when the number ofS. aureusexceeded 107per g in aseptically peeled shrimp. Results indicate thatS. aureusis able to produce enterotoxin in shrimp, but its production depends upon a number of factors, including the relationship betweenS. aureusand competitive micro-organisms. It is concluded that the presence ofS. aureuson commercially produced shrimp represents a potential hazard to health.