The optimal mode of transport for swabs obtained from surfaces examined for organisms causing food-borne disease

Abstract

SUMMARY: An investigation was carried out on the influence of the mode of transport at ca. 21° C. on the fate ofS. typhimurium,E. coli, Ps. aeruginosa, Staph. aureus, Str. pyogenesand spores ofB. cereuscollected from surfaces by swabbing with cotton and alginate.Transport at relative humidity 0·58–0·95 leads to losses in viable counts sometimes exceeding two log cycles. In Stuart's medium and Ringer-calgon particularly Enterobacteriaceae showed growth when transported at 21° C. Reduction of the pH value of Stuart's medium led to losses of far over one log cycle in some types of bacteria and could therefore not be recommended.Slight chilling of the medium, e.g. to 12° C., and insulation during transport appeared to maintain counts of the organisms studied at their original level in both Stuart's medium and Ringer calgon for 10–12 hr.