Development of selective co-enrichment medium for Salmonella, Staphylococcus aureus and Vibrio parahaemolyticus

Abstract

ObjectiveA co-enrichment medium SSV which can simultaneously enrich Salmonella， Staphylococcus aureus and Vibrio parahaemolyticus was developed for the simultaneous detection of the above three foodborne pathogens in foods.MethodsAccording to the nutritional needs of the three strains， the medium components were selected by single factor experiments， and the formula of selective co-enrichment medium was developed. The SSV medium was verified through bacterial number change， injured bacteria recovery， multiple polymerase chain reaction （PCR） and medium selectivity.ResultsThe components of enrichment medium were determined as followed： Peptone 10.0 g， KH2PO4 1.5 g， NaCl 15.0 g， LiCl 1.0 g， Na2S2O3 5.0 g， sodium deoxycholate 0.05 g， mannitol 1.0 g， sodium pyruvate 5.0 g and distilled water 1 000 mL. The above three strains could be enriched in SSV medium at the same time. After cultured at 37 ℃ for 16 h， the cell concentrations of the three strains reached 107 CFU/mL at least. SSV medium had a good resuscitation effect on the damaged target bacteria， and the OD600 nm tripled after resuscitatio. At the same time， the function was well verified by multiplex PCR and medium selectivity.ConclusionThe co-enrichment medium SSV can be used to simultaneously culture Salmonella， Staphylococcus aureus and Vibrio parahaemolyticus. The preparation of the medium is simple and cost-effective. It can be combined with multiplex PCR to improve the detection rate and accuracy.

Keywords

• co-enrichment medium
• salmonella enteritidis
• staphylococcus aureus
• vibrio parahaemolyticus
• recovery of injured bacteria