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Quantification of viable protozoan parasites on leafy greens using molecular methods.
- 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.)
- Subjects :
- Animals
Azides chemistry
Cryptosporidium parvum chemistry
Cryptosporidium parvum genetics
Cryptosporidium parvum growth & development
Food Contamination analysis
Giardia chemistry
Giardia genetics
Giardia growth & development
Oocysts chemistry
Oocysts growth & development
Oocysts isolation & purification
Plant Leaves parasitology
Propidium analogs & derivatives
Propidium chemistry
Real-Time Polymerase Chain Reaction
Staining and Labeling
Toxoplasma chemistry
Toxoplasma genetics
Toxoplasma growth & development
Cryptosporidium parvum isolation & purification
Food Parasitology methods
Giardia isolation & purification
Spinacia oleracea parasitology
Toxoplasma isolation & purification
Subjects
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