Evaluation of two analytical methods of detection for intestinal parasites in curly lettuce sold in food stalls

Joazir Rodrigues Oliveira,Adelino Da Cunha Neto,Sirbene Nunes Da Cunha,Vinicius Silva Castro,Rafaela Cássia Da Cunha Pedroso

doi:10.1590/1981-6723.00221

Abstract

Abstract This study aimed to investigate the occurrence of parasitic structures in curly lettuce (Lactuca sativa L.) sold in food stalls open markets in Cuiabá city, in the Brazilian state of Mato Grosso (MT). For this purpose, 50 samples were evaluated using spontaneous sedimentation and centrifugal flotation methods. These techniques showed positivity in 96% (48/50) and 78% (39/50) of the samples, respectively. The sedimentation method was statistically (p ≤ 0.05) more effective in detecting parasitic structures of the pathogens as Entamoeba histolytica, Ascaris spp., Strongyloides spp., Larvae and Hookworm eggs, when comparing both methods. However, these methods did not differ significantly for the detection of Giardia lamblia. Ascaris spp and Entamoeba coli occurred in 64% (32/50) and 46% (23/50) of the positive samples, respectively, with the highest percentages observed. The occurrence of Blastocystis spp., Fasciola spp., Dipylidium caninum and Ascaris lumbricoides revealed detection exclusively by the spontaneous sedimentation method, while Iodamoeba butschlii and Enterobius vermicularis were detected by centrifugal– flotation procedure. These results could reinforce the need to use methods based on sedimentation and the fluctuation of parasite structures in the analysis of lettuce. The presence of parasites in lettuce by fecal origin, with recognized pathogenicity, represents a risk to consumer health and demonstrates a deficit in good agricultural practices in the production, distribution and commercialization of lettuce.

Highlights

Parasites are one of the disease-causing agents in humans, as well as bacteria, viruses, and protozoa, defined by the World Health Organization (WHO) (World Health Organization, 2015)
Lettuces processed by the spontaneous sedimentation method showed positivity for parasitic structures in 96% (48/50) of the samples
By using two different methods of parasitological analysis, we found that the lettuces sold at the open-markets in Cuiabá (MT) showed a high frequency of parasitic structures of the different family, genus, and species of the protists (Protozoa) and helminths (Metazoa) (Table 1)

Summary

Introduction

Parasites are one of the disease-causing agents in humans, as well as bacteria, viruses, and protozoa, defined by the World Health Organization (WHO) (World Health Organization, 2015). Some parasites can cause diarrheal diseases, as Cryptosporidium spp., Entamoeba histolytica and Giardia spp. Diseases that affect the abdomen (Ascaris spp., Fasciola spp. etc.), lung, liver and Central Nervous System (CNS) (Echinococcus granulosus and E. multilocularis, Taenia solium - cysticercosis). These parasites are among the pathology's causative agents, sometimes disabling the consumer’s health (World Health Organization, 2015). Other parasite species were included recently as Toxoplasma gondii and T. solium (Food and Agriculture Organization of the United Nations, 2016) Some genera such as Giardia spp., Cryptosporidium spp., Ascaris spp., and E. histolytica are related to parasites that trigger foodborne diseases most frequently (World Health Organization, 2015)

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