title: Standardization of a method for the detection of helminth eggs and larvae in lettuce.
abstract: Despite reports that food-borne parasitic infections have been increasing worldwide, the methodologies employed to detect food contamination by helminths are still largely based on methodologies used to detect these pathogens in feces and water. This study sought to improve the diagnosis of parasitic contaminants in lettuce by standardizing a method for detecting helminth eggs and larvae and estimating their percentage of recovery. Sanitized lettuces were artificially contaminated with different amounts of Ascaris suum and hookworm eggs and larvae. To standardize the method, we tested liquid extractors, vegetable washing steps, and spontaneous sedimentation times. Higher percentages of egg and larvae recovery were obtained using 1 M glycine as the liquid extractor, manual shaking for 3 min and 2 h of sedimentation. Five different levels of artificial contamination (ten replicates each; n = 50) were tested using these standardized conditions, yielding an average recovery of 62.6 % (±20.2), 51.9 % (±20.0), and 50.0 % (±27.3) for A. suum eggs, hookworm eggs, and larvae, respectively. Tests were performed with a different matrix to evaluate the performance of the method. Furthermore, collaborative analytical studies performed by different laboratories produced satisfactory results. The method for the identification of helminth eggs and larvae proposed in this study proved to be simpler and more efficient than previously published procedures, thereby demonstrating its potential contribution to health surveillance and epidemiological studies.
authors.affiliation: Serviço de Microscopia de Produtos do Instituto Otávio Magalhães da Fundação Ezequiel Dias, Belo Horizonte, Brazil.
authors.forename: F C
authors.initials: FC
authors.lastname: Matosinhos
authors.affiliation: Serviço de Microscopia de Produtos do Instituto Otávio Magalhães da Fundação Ezequiel Dias, Belo Horizonte, Brazil.
authors.forename: V C
authors.initials: VC
authors.lastname: Valenzuela
authors.affiliation: Departamento de Parasitologia - Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, CEP 31270-901, Belo Horizonte, MG, Brazil.
authors.forename: J A
authors.initials: JA
authors.lastname: Silveira
authors.affiliation: Departamento de Parasitologia - Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, CEP 31270-901, Belo Horizonte, MG, Brazil. elidam.rabelo@gmail.com.
authors.forename: E M
authors.initials: EM
authors.lastname: Rabelo
mesh_terms: D000723:Ancylostomatoidea / Q000302:isolation & purification*; D000818:Animals; D017165:Ascaris suum / Q000302:isolation & purification*; D005243:Feces / Q000469:parasitology; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D007814:Larva; D018545:Lactuca / Q000469:parasitology*; D009865:Oocytes; D010270:Parasite Egg Count / Q000379:methods*
keywords: Detection technique; Food contamination; Helminth eggs; Helminth larvae; Leafy vegetables