Evaluation of different buffered peptone water (BPW) based enrichment broths for detection of Gram-negative foodborne pathogens from various food matrices.
This study evaluated the effects of changing the composition of the pre-enrichment medium buffered peptone water (BPW) on the growth of stressed and unstressed Gram-negative foodborne pathogens in a one-broth enrichment strategy. BPW supplemented with an available iron source and sodium pyruvate, along with low levels of 8-hydroxyquinoline and sodium deoxycholate (BPW-S) improved the recovery of desiccated Cronobacter spp. from powdered infant formula. Growth of Salmonella and STEC was comparable in all BPW variants tested for different food matrices. In products with high levels of Gram-negative background flora (e.g. sprouts), the target organisms could not be reliably detected by PCR in any of the BPW variants tested unless the initial level exceeded 10(3) cfu/10 g of sprouts. Based on these results we suggest BPW-S for a one-broth enrichment strategy of stressed Gram-negative foodborne pathogens from dry products. However, a one-broth enrichment strategy based on BPW variants tested in this evaluation is not recommended for produce with a high level of Gram-negative background flora due to very high detection limits.
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, CH-8057 Zurich, Switzerland.
H
H
Margot
Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands.
M H
MH
Zwietering
European Chair in Food Safety Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands.
H
H
Joosten
Quality and Safety Department, Nestlé Research Center, Vers-chez-les-Blanc, CH-1000 Lausanne, Switzerland.
Emer
E
O'Mahony
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, CH-8057 Zurich, Switzerland. Electronic address: stephanr@fsafety.uzh.ch.
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R
Stephan
D003470:Culture Media / Q000737:chemistry*; D003840:Deoxycholic Acid / Q000737:chemistry; D005516:Food Microbiology / Q000379:methods*; D006801:Humans; D007223:Infant; D041943:Infant Formula / Q000382:microbiology*; D015125:Oxyquinoline / Q000737:chemistry; D010461:Peptones / Q000737:chemistry; D016133:Polymerase Chain Reaction; D019289:Pyruvic Acid / Q000737:chemistry; D012475:Salmonella / Q000254:growth & development / Q000302:isolation & purification*; D014867:Water
D003470:Culture Media; D010461:Peptones; D003840:Deoxycholic Acid; D014867:Water; D015125:Oxyquinoline; D019289:Pyruvic Acid
Cronobacter; Enterobacteriaceae; One-broth strategy; Pre-enrichment; Resuscitation; STEC; Salmonella; Supplements