Detection of Cyclospora cayetanensis, Cryptosporidium spp., and Toxoplasma gondii on imported leafy green vegetables in Canadian survey

To investigate the prevalence of protozoan contamination by Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii and Cyclospora cayetanensis, in 'ready to eat' (RTE) salads on sale in Italy, 648 packages were purchased from industrial and local brands. Nine individual packages from each brand were collected per month, pooled and subjected to microscopy and molecular analyses. Microscopic examination of 864 slides detected Cryptosporidium spp. but also Blastocystis hominis and Dientamoeba fragilis. Molecular tools identified G. duodenalis assemblage A, Cryptosporidium parvum and Cryptosporidium ubiquitum, T. gondii Type I and C. cayetanensis. B. hominis and D. fragilis were also molecularly confirmed. The overall prevalence of each protozoan species was 0.6% for G. duodenalis, 0.8% for T. gondii, 0.9% for Cryptosporidium spp., and 1.3% for C. cayetanensis, while prevalence for B. hominis was 0.5% and for D. fragilis 0.2%. Microscopy and/or molecular tools revealed that 4.2% of the samples were contaminated by at least one protozoan species, and 0.6% of samples presented contamination by two protozoan species, with a number of oocysts ranging from 62 to 554 per g of vegetable matter for T. gondii, and 46 to 1.580 for C. cayetanensis. This is Europe's first large-scale study on the presence of protozoans in packaged salads, and shows that RTE sanitation processes do not guarantee a product free from protozoans of fecal origin.

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“…(2013) in Canada, where T. gondii was also detected but with a lower prevalence (Lalonde and Gajadhar, 2016) than in the present study (0.8%).…”

Section: Discussioncontrasting

confidence: 66%

Detection and prevalence of protozoan parasites in ready-to-eat packaged salads on sale in Italy

et al. 2017

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“…The 529-bp DNA fragment was amplified in 40% of all samples, with an estimated mean of 23.5 oocysts per gram of product. Our findings indicate a higher prevalence compared to other studies [19][20][21][22][23][24][25][26]. However, critical analysis of the data in Table 3, evidences major differences related to: (i) sampling design; (ii) DNA target strategy; and of relevance to this particular study (iii) the choice of oocyst recovery method.…”

Section: Discussioncontrasting

confidence: 47%

“…So far, the detection of Toxoplasma oocysts in fruit and vegetables has been difficult, and no standardized methods are available. Moreover, findings outlined in the literature on this topic are scarce and/or controversial [19][20][21][22][23][24][25][26]. In this scenario, a laboratory approach was designed based on the experience gained with Method 1623.1/EPA for Cryptosporidium oocyst and Giardia cyst detection [27].…”

Section: Introductionmentioning

confidence: 99%

Detection of Toxoplasma gondii oocysts in fresh vegetables and berry fruits

et al. 2020

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Background: Toxoplasma gondii is the third most important contributor to health burden caused by food-borne illness. Ingestion of tissue cysts from undercooked meat is an important source of horizontal transmission to humans. However, there is an increasing awareness of the consumption of fresh fruit and vegetables, as a possible source for oocyst transmission, since this stage of the parasite can persist and remain infective in soil and water for long time. Herein, we outline findings related with detection of T. gondii oocysts in vegetables and berry fruits, which are usually raw consumed. The procedure includes the estimation of the number of oocysts. Methods: Food samples were collected from local producers and supermarket suppliers. Toxoplasma gondii oocysts were concentrated after washing the samples by applying high resolution water filtration and immunomagnetic separation (method 1623.1: EPA 816-R-12-001-Jan 2012), in order to (i) remove potential Cryptosporidium spp. oocysts and Giardia spp. cysts present in the samples; and (ii) select T. gondii oocysts. Toxoplasma gondii oocyst detection and an estimation of their numbers was performed by conventional PCR and real time qPCR, using specific primers for a 183-bp sequence of the T. gondii repetitive DNA region. All PCR-positive DNA samples were purified and sequenced. Restriction enzyme digestion with EcoRV endonuclease confirmed the presence of the T. gondii DNA fragment. In addition, the presence of the parasite was observed by fluorescent microscopy, taking advantage of the oocysts autofluorescence under UV light. Results: Forty percent of the analysed samples (95% CI: 25.5-56.5%) presented the expected PCR and digested DNA fragments. These fragments were confirmed by sequencing. Microscopic autofluorescence supported the presence of T. gondii-like oocysts. The estimated mean (± SE) oocyst concentration was 23.5 ± 12.1 oocysts/g, with a range of 0.6-179.9 oocysts/g. Conclusions: Our findings provide relevant evidence of contamination of fresh vegetables and berry fruits with T. gondii oocysts.

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“…minced meat). This approach also applies to other food matrices where contamination by T. gondii has been reported such as vegetables (Lalonde and Gajadhar, 2016) and goat milk (Dubey et al, 2014;Fusco et al, 2007).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Knowledge gaps in host-parasite interaction preclude accurate assessment of meat-borne exposure to Toxoplasma gondii

Crotta

Limon

Blake

et al. 2017

International Journal of Food Microbiology

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Detection of Cyclospora cayetanensis, Cryptosporidium spp., and Toxoplasma gondii on imported leafy green vegetables in Canadian survey

Cited by 46 publications

References 20 publications

Detection and prevalence of protozoan parasites in ready-to-eat packaged salads on sale in Italy

Detection and prevalence of protozoan parasites in ready-to-eat packaged salads on sale in Italy

Detection of Toxoplasma gondii oocysts in fresh vegetables and berry fruits

Knowledge gaps in host-parasite interaction preclude accurate assessment of meat-borne exposure to Toxoplasma gondii

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