Microbiological evaluation of lettuce produced by conventional and organic systems in farms of Londrina, PR

Abstract

The aims of this study were to evaluate the contamination of lettuce (Lactuca sativa), produced in Londrina, Paraná (PR), with total coliform, coliform at 45 °C, E. coli, and Salmonella spp.; and to determine the E. coli contamination of irrigation water used at the farms studied. Four farms were evaluated, of which three produced lettuce using a conventional system and one using an organic system. An evaluation of the production practices of the farms was also carried out. A total of 111 samples were analyzed, 71 lettuce samples from the conventional system and 40 samples from the organic system. A total of eight irrigation water samples were collected for analysis. Coliform at 45 °C counts above the limit tolerated by Brazilian legislation were observed in 2.8% (2/71) of conventionally grown lettuce samples, and Salmonella spp. was isolated in 1.4% (1/71) of those samples. In the organic lettuce samples, 12.5% (5/40) had coliform at 45 °C counts above the limit tolerated and Salmonella spp. was not detected. Irrigation water samples from three farms were unsatisfactory, with counts higher than 10 2 MPN of E. coli per 100mL. The results of this study demonstrate that most conventionally grown lettuce samples show good sanitary conditions in production, and that lettuce contamination is not related to contamination found in irrigation water samples. The results also showed that the organic production practices required by Brazilian certification agencies should be applied to ensure that contamination of produced lettuce remains controlled. Key words: Coliform at 45 °C. Total coliform.Salmonella spp. Irrigation water. ResumoOs objetivos deste estudo foram avaliar a contaminação por coliformes totais, coliformes a 45 °C, Escherichia coli e Salmonella spp. em alfaces crespas (Lactuca sativa) produzidas na região de Londrina, PR, e a contaminação por E. coli das amostras da água de irrigação empregadas nas propriedades estudadas. Quatro propriedades rurais foram avaliadas, das quais três produziam alfaces pelo sistema convencional e uma pelo sistema orgânico. Avaliação das práticas de produção dessas propriedades também foi realizada. Um total de 111 amostras foi coletado, sendo 71 amostras de produção convencional e 40 amostras de produção orgânica. Oito amostras de água de irrigação foram coletadas para análise. Contagens de coliformes a 45 °C acima do tolerado pela legislação brasileira foram observadas em 2,8 % (2/71) das alfaces convencionais analisadas, e Salmonella spp. foi isolada em 1,4 % (1/71) destas amostras. de coliformes a 45 °C acima do limite preconizado e Salmonella spp. não foi isolada nessas amostras. As amostras de água de irrigação de três propriedades rurais apresentaram resultados insatisfatórios com contagens superiores a 10 2 MPN de E. coli por 100 mL. Os resultados obtidos neste estudo mostraram que a maioria das amostras de alfaces convencionais analisadas apresentou boas condições higiênico-sanitárias e uma não relação com a contaminação encontrada nas amostras de água de irrigaçã...

Escherichia coli and Salmonella sp. on some lettuce in the traditional market of Banyuwangi Regency

“…This finding was also supported by research by Niguma et al on four lettuce plantations in Londrina, Brazil, which showed that 1 (1.4%) of lettuce grown using conventional techniques contained Salmonella sp. In contrast, Salmonella sp was not detected on all organically grown lettuces (Niguma et al, 2017).…”

Hygienic-sanitary quality of lettuce (Lactuca sativa) and arugula (Eruca sativa) produced in an organic farm system in Cuiabá, MT, Brazil

“…Thermotolerant coliform counts in the investigated water samples were mostly below the maximum acceptable limits, while most fertilizer samples (animal and vegetable) presented counts above the maximum established limits (ICMSF, 2015). Thus, good agricultural practices in the handling and use of water and fertilizer inputs seem to not have been followed on the investigated property, as following the Good Agricultural Practices (GAP) program results in low or absent counts of this group of organisms (NIGUMA et al, 2017). At the assessed property, vegetables are harvested and sold directly to the final consumer.…”