Immunomagnetic separation of Salmonella from foods and their detection using immunomagnetic particle (IMP)-ELISA

Int J Food Microbiol. 1995 Sep;27(1):11-25. doi: 10.1016/0168-1605(94)00134-r.

Abstract

An immunomagnetic particle based ELISA (IMP-ELISA) for the detection of Salmonella from foods has been developed using Dynabeads anti-Salmonella (Dynal, Oslo, Norway). Appropriate sample preparation protocols to allow rapid detection of Salmonella serovariants in processed (powdered egg products) and non-processed (raw chicken) samples have been established. Pre-enriched broths of heat processed samples likely to harbour only low levels of competitive enteric flora, were boiled and used directly for IMP-ELISA. For non-heat processed or raw samples likely to contain higher numbers of such competing organisms, live Salmonella cells were first isolated by immunomagnetic separation (IMS) from standard pre-enrichment broths, and then post-selectively enriched for a short time in M-broth followed by boiling before IMP-ELISA. The total assay time including sample preparation was under 26 h for both types of procedure, with a lower detection limit of 10(5) Salmonella cells/ml of sample. In an evaluation of naturally contaminated poultry samples, all 45 of 48 samples previously shown to contain salmonellae in a comparison of ISO, IMS-Plating, Salmonella-Tek ELISA (Organon Teknika, Inc. Durham, NC) and a modification of the latter based on IMS, were identified as positive. None of the other methods gave positives for all 45.

MeSH terms

  • Animals
  • Antigens, Bacterial / isolation & purification
  • Chickens
  • Eggs / microbiology*
  • Enzyme-Linked Immunosorbent Assay
  • Feasibility Studies
  • Food Microbiology
  • Immunomagnetic Separation
  • Meat / microbiology*
  • Salmonella / immunology
  • Salmonella / isolation & purification*
  • Sensitivity and Specificity

Substances

  • Antigens, Bacterial