Back to Search Start Over

Quantification of viable protozoan parasites on leafy greens using molecular methods.

Authors :
Kim M
Shapiro K
Rajal VB
Packham A
Aguilar B
Rueda L
Wuertz S
Source :
Food microbiology [Food Microbiol] 2021 Oct; Vol. 99, pp. 103816. Date of Electronic Publication: 2021 Apr 17.
Publication Year :
2021

Abstract

Protozoan contamination in produce is of growing importance due to their capacity to cause illnesses in consumers of fresh leafy greens. Viability assays are essential to accurately estimate health risk caused by viable parasites that contaminate food. We evaluated the efficacy of reverse transcription quantitative PCR (RT-qPCR), propidium monoazide coupled with (q)PCR, and viability staining using propidium iodide through systematic laboratory spiking experiments for selective detection of viable Cryptosporidium parvum, Giardia enterica, and Toxoplasma gondii. In the presence of only viable protozoa, the RT-qPCR assays could accurately detect two to nine (oo)cysts/g spinach (in 10 g processed). When different proportions of viable and inactivated parasite were spiked, mRNA concentrations correlated with increasing proportions of viable (oo)cysts, although low levels of false-positive mRNA signals were detectable in the presence of high amounts of inactivated protozoa. Our study demonstrated that among the methods tested, RT-qPCR performed more effectively to discriminate viable from inactivated C. parvum, G. enterica and T. gondii on spinach. This application of viability methods on leafy greens can be adopted by the produce industry and regulatory agencies charged with protection of human public health to screen leafy greens for the presence of viable protozoan pathogen contamination.<br /> (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Details

Language :
English
ISSN :
1095-9998
Volume :
99
Database :
MEDLINE
Journal :
Food microbiology
Publication Type :
Academic Journal
Accession number :
34119101
Full Text :
https://doi.org/10.1016/j.fm.2021.103816