Comparison of methods for the recovery and detection of low levels of injured Salmonella in ice cream and milk powder

This study compared the ability of four rapid methods and a standard cultur al method to detect low levels of heat-injured cells of Salmonella typhimur ium in ice cream and skimmed milk powder. The detection of Salmonella in sa mples contaminated with low levels (< 10 cfu 25 g(-1)) was significantly gr eater with the novel broth method than with the other methods (P less than or equal to 0.01). At contamination levels > 10 cfu 25 g(-1), there was no significant difference between the methods except for the novel broth metho d and a dipstick-based immunoassay (P less than or equal to 0.05). The nove l broth method, S.P.R.I.N.T. Salmonella, which incorporates a specifically formulated peptone and Oxyrase(R) combination followed by the timed release of selective agents into the recovery medium, was shown to improve the rat e of detection of low numbers of injured cells of Salmonella after 24 h enr ichment.