Evaluation of ISO Enrichment Real

Evaluation of ISO enrichment real-time PCR methods with internal amplification control for detection of Listeria monocytogenes and Salmonella enterica in fresh fruit and vegetables.

Lett Appl Microbiol. 2009 Jul;49(1):105-11. Epub 2009 Apr 22.

Badosa E, Chico N, Pla M, Parés D, Montesinos E.

Institut de Tecnologia Agroalimentària - CeRTA-CIDSAV, Universitat de Girona, Girona, Spain.

AIMS: To provide with a quick method for qualitative detection, in less than three days, of Salmonella enterica and Listeria monocytogenes in fresh fruit and vegetables. METHODS AND RESULTS: The method was based on coupling International Standard Organization (ISO) enrichment to a real-time PCR with internal amplification control (IAC), in a duplex format, without additional DNA purification. The performance was tested on different plant products. Both bacterial pathogens were consistently detected with a limit of detection (LOD) of 1 CFU in 25 g after enrichment, except for soybean sprouts. Levels of S. enterica, ranging from 1 to 10 CFU in 25 g after enrichment were detected with different enrichment broths. CONCLUSIONS: For both pathogens, the LOD was similar to that of the corresponding ISO method, while decreasing the analysis time and handling needs. SIGNIFICANCE AND IMPACT OF THE STUDY: The agreement between standard ISO and the enrichment real-time PCR(IAC)-based methods make the latter method as a promising alternative for quick and reliable detection of food-borne pathogens in fresh fruit and vegetables in routine laboratories.