Rapid detection of stressed Salmonella spp. in dairy and egg products using immunomagnetic separation and PCR

• Published in: International journal of food microbiology 1999-01, Vol.46 (1), p.37-44
• Main Authors: Rijpens, Nancy, Herman, Lieve, Vereecken, Freia, Jannes, Geert, De Smedt, Jef, De Zutter, Lieven
• Format: Article
• Language: English
• Subjects: Base Sequence; Biological and medical sciences; Colony Count, Microbial; Dairy and egg products; Dairy Products - microbiology; DNA Primers - chemistry; DNA, Bacterial - chemistry; Egg and egg product industries; EGG PRODUCTS; Eggs - microbiology; Electrophoresis, Agar Gel; Food industries; FOOD INSPECTION; Food Microbiology; Fundamental and applied biological sciences. Psychology; Immunomagnetic Separation; IMS; INSPECCION DE LOS ALIMENTOS; INSPECTION DES ALIMENTS; Milk and cheese industries. Ice creams; MILK PRODUCTS; Molecular Sequence Data; OVOPRODUIT; PCR; Polymerase Chain Reaction; PRODUCTOS DERIVADOS DEL HUEVO; PRODUCTOS LACTEOS; PRODUIT LAITIER; SALMONELLA; Salmonella - genetics; Salmonella - growth & development; Salmonella - isolation & purification; Salmonella Food Poisoning - prevention & control; Sequence Analysis, DNA
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/S0168-1605(98)00171-8

The rapid detection of an average of 5.9 stressed Salmonella cells in 25 g of food product using immunomagnetic separation (IMS) and PCR is described. For pasteurised egg yolk, egg yolk powder, ice-cream, whole egg, egg white and cheeses made from pasteurised milk PCR was applied after 16 h of preenrichment in buffered peptone water (BPW) using IMS and alkaline lysis as sample preparation method. For whole egg and egg white the BPW was supplemented with iron. For milk powder, and raw milk cheeses, the 16-h preenrichment in BPW was followed by IMS and a 4-h enrichment in Rappaport–Vassiliadis broth. In the latter case, PCR was applied on the enrichment medium after centrifugation and alkaline lysis. For PCR the primers ST11 and ST15 ( Aabo et al., 1993) producing a fragment of 429 bp were used. An internal PCR control, designed to be co-amplified with the target DNA using the same primers but producing a smaller fragment of 240 bp, was used.