Rapid detection of trace Salmonella in milk and chicken by immunomagnetic separation in combination with a chemiluminescence microparticle immunoassay
- 35 Downloads
Rapid detection of trace Salmonella is urgently needed to ensure food safety. We present an innovative pretreatment strategy, based on a two-step enrichment culture and immunomagnetic separation, combined with a chemiluminescence microparticle immunoassay to detect at least one proliferative Salmonella cell in 25 mL (25 g) food. The capture performance of immunomagnetic beads (IMBs) of sizes for Salmonella was investigated, and the IMBs of size 2.8 μm showed a high capture efficiency of 60.7% in 25 mL milk and 74.5% in 25 mL chicken culture filtrate, which ensured the successful capture of trace Salmonella after 2.5 h in situ enrichment even from only one Salmonella cell. The separated Salmonella cells, reaching an amount of 103 colony-forming units (CFU) by a secondary enrichment for 3 h, were detected by a horseradish peroxidase chemiluminescence reaction with 4-(1-imidazolyl)phenol as an enhancer, which evidenced a linear response for Salmonella concentrations ranging from 2.3 × 102 to 7.8 × 104 CFU/mL. The entire detection process was completed within 8 h, with a very low detection limit of 1 CFU/25 mL (25 g), which was verified by colony counting, and a small degree of interference of 0.17–1.06%. Trace Salmonella from five different serovars in milk and chicken was successfully detected without false negative or false positive results. Furthermore, this study provides a basis to develop a fully automated instrument based on IMBs that includes all steps from sample preparation to chemiluminescence microparticle immunoassay for high-throughput screening of foodborne pathogens.
KeywordsPretreatment Pathogen Chemiluminescence immunoassay Enrichment Food safety
This work was supported by the National Key Scientific Instrument and Equipment Development Projects (grant number 2013YQ140371) and the Building of Innovative Team Plan (grant number IG201807C1).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests.
- 27.International Organization for Standardization. EN ISO 16654:2001. Microbiology of food and animal feeding stuffs—horizontal method for the detection of Escherichia coli O157.Google Scholar
- 28.International Organization for Standardization. ISO 15553:2006. Isolation and identification of Cryptosporidium oocysts and Giardia cysts in waters.Google Scholar
- 30.US Environmental Protection Agency. Method 1623: Cryptosporidium and Giardia in water by filtration/IMS/FA. Office of Water EPA-821-R-99–006. Cincinnati: US Environmental Protection Agency; 1999.Google Scholar
- 31.General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China. SNT 0184.3-2008 determination of Listeria monocytogenes in food for import and export, Beijing; 2008.Google Scholar
- 39.Standardization Administration of the People's Republic of China. GB 4789.4-2016 national food safety standard. Food microbiological examination: Salmonella.Google Scholar
- 42.Antunović B. Influence of milk product type and its initial contamination on the efficiency of different methods for detection of Salmonella Enteritidis, Listeria monocytogenes and Escherichia coli O157:H7. Mljekarstvo. 2018:3–11.Google Scholar
- 44.Ye J, Liu Y, Li Y. Chemiluminescence fiber-optic biosensor coupled with immunomagnetic separation for rapid detection of E. coli O157: H7. Trans ASAE. 2002;45:473–8.Google Scholar
- 50.Magliulo M, Simoni P, Guardigli M, Michelini E, Luciani M, Lelli R, et al. A rapid multiplexed chemiluminescent immunoassay for the detection of Escherichia coli O157:H7, Yersinia enterocolitica, Salmonella typhimurium, and Listeria monocytogenes pathogen bacteria. J Agric Food Chem. 2007;55(13):4933–9.CrossRefGoogle Scholar