Detection methods and prevalence of transmission stages of Toxoplasma gondii, Giardia duodenalis and Cryptosporidium spp. in fresh vegetables: a review

Abstract

One of the ways of human parasitic infection is the accidental ingestion of vegetables contaminated with parasites, which represents a major human health hazard. This non-exhaustive review aims to evaluate studies carried out on five types of vegetables (lettuce, parsley, coriander, carrot and radish) since 2000, particularly the methods used for recovery, concentration, detection and identification of protozoan parasites such as Toxoplasma gondii, Giardia duodenalis and Cryptosporidium spp., and the results of each work. Various studies have determined the presence of pathogenic parasites in fresh vegetables with different rates; this variation in rate depends particularly on the detection method used which is related to each parasite and each vegetable type. The variation in parasitic prevalence in food could be due to different factors such as the geographical location, the size of analysed samples and the methods used for parasite detection.

Detection of human intestinal protozoan parasites in vegetables and fruits: a review

“…Another study in the Czech Republic reported a significantly higher contamination of T. gondii in vegetables collected from farm storage rooms than those from fields [64], indicating a higher chance of contamination of vegetables and fruits during processing and selling [78]. Therefore, the adaptation of good practices in every step between farm and fork, such as production, processing, storage and selling minimize the microbial contamination of vegetables and fruits.…”

Update on Giardia: Highlights from the seventh International Giardia and Cryptosporidium Conference

“…Giardia in environmental waters, seafood, and fresh produce Giardia causes water-and foodborne outbreaks of diarrheal illness globally [28]. In particular, waterborne transmission is of major importance in the epidemiology of the parasite and still constitutes a serious public health concern [8,22]. To date, Giardia is known to exist in eight distinct assemblages, or genotypes, from A to H, where A and B are infectious to humans.…”

Determination of the Occurrence of Toxoplasma Gondii, Giardia Duodenalis and Cryptosporidium spp. in leafy Greens in Marrakech using a Molecular Method

“…Surveillance studies from around the world reported widely varying contamination rates for the three protozoan in leafy greens, attributable to differing sampling strategies, geographic location, sanitation and detection methodologies. Parasitic (oo) cysts have usually been monitored in food matrices following three steps: elution, concentration and detection [22]. The difference in properties of the various food matrices could make it di cult to remove and detect protozoan (oo) cysts [2].…”

“…In addition, this standard is based on immunomagnetic separation technique followed by immuno uorescent assay for detection that are expensive, time consuming and require a microscopy expertise, making this method di cult to use for routine checks by food processors. Therefore, there have been a multitude of described methods worldwide for parasitic detection in vegetable matrices with different recovery e ciencies and detection levels [22]. This contributes to the under diagnosis of protozoan parasites in food.…”