Attachment and inactivation of Vibrio parahaemolyticus on stainless steel and glass surface

Abstract

Vibrio parahaemolyticus is an important food-borne pathogen in Asia. Strains of this pathogen are commonly associated with seafood and may attach to abiotic surfaces during food processing. This work investigates the attachment, biofilm formation and inactivation of this pathogen, on stainless steel and glass surfaces. Attachment of V. parahaemolyticus to these abiotic surfaces was influenced by the growth phase, composition of the culture medium, and stress treatments of the bacterial cells, and also by the presence of sugars in the bacterial suspension. Bacterial culture grown in synthetic MM9 significantly attached more than did the tryptic soy broth culture. Attachment was reduced in the bacterial cultures subjected to various stress treatments, such as low-temperature treatment at 4°C, heat shock at 42°C or two-phase acid adaptation at pH 5·8 and 5·0. Sugars in the bacterial suspension significantly inhibited the attachment, while melibiose, raffinose and stachyose were superior to other sugars as attachment inhibitors to a stainless-steel surface. Clinical strains attached better on stainless steel surface than did environmental strains. V. parahaemolyticus did not form a biofilm effectively in the batch-type culture. The bacterial cell density increased and reached a maximum at 6 or 8 h on stainless steel and glass surfaces, respectively, and declined thereafter. The cells attached on stainless-steel surface were readily inactivated by distilled water, sodium hypochlorite or propionic acid.