Influence of different sources of contamination on the microbiological quality of lettuce in the Teresópolis region, RJ, Brazil

Abstract

Irrigation water and cultivated soil have been identified as possible sources of contamination in several crops. In certain vegetables that are eaten raw, such as lettuce, this contamination can lead to public health problems. Aiming to evaluate the influence of these sources on the quality of lettuce grown in the Córrego Sujo Basin, Teresópolis, RJ, an important agricultural pole whose production services the metropolitan region of Rio de Janeiro, water from different sources (spring, weir and river) was collected in this region, as well as samples of soil and lettuce irrigated with these waters, to carry out conventional microbiological analyzes (counts of total heterotrophic bacteria and thermotolerant coliforms) and molecular analyzes (PCR-DGGE). The count of fecal coliforms in lettuce suggests that there is an influence of irrigation water and the cultivated soil on the contamination of these vegetables. The grouping of bacterial communities in the different samples obtained by the PCR-DGGE technique shows that irrigation water has a greater influence on the contamination of these vegetables in relation to the soil where they are grown. These results corroborate the need to monitor water bodies used for irrigation and demonstrate that the PCR-DGGE technique is of great value for the study of microbial communities and, when associated with specific primers, can help in the detection of pathogens in food.

Segurança microbiológica de hortaliças orgânicas no Brasil

“…O número de casos de infecções intestinais tem aumentado consideravelmente com o passar dos anos, acompanhando o aumento de ingestão de hortaliças mundialmente (Nunes- Carvalho, 2020).…”

“…Dentre os grupos bacterianos mais frequentemente associadoas a DTAs pode-se destacar duas espécies bacterianas pertencentes à família Enterobacteriacea, Escherichia coli e Salmonella spp., além de Staphylococcus, Listeria monocytogenes. Clostridium, Shigella e Campylobacter (Beltrão et al, 2019;Carvalho et al, 2019;Fung et al, 2018;Nunes-Carvalho, 2020).…”

Lettuce Fertigation with Domestic Effluent Treated with Orange Pomace Biochar

“…Concerns with irrigation using treated wastewater include risks to soil quality and crop development [17]. Nunes-Carvalho et al [18] warn that the presence of fecal contamination in irrigation water represents a serious public health problem, especially for irrigation of vegetables that are consumed raw. Thus, the use of filter materials such as biochar as a tool in the adsorption process presents itself as an alternative to improve the microbiological quality of the treated effluent.…”

Análise de dados do Sistema de Informação de Vigilância da Qualidade da Água para Consumo Humano (Sisagua) no estado do Amazonas, 2016-2020

“…No entanto, pesquisas vêm demonstrando que nem sempre esse recurso hídrico disponibilizado para a população é adequado para o consumo, sendo diagnosticada a presença de níveis microbiológicos, químicos e físico-químicos fora do preconizado pelos órgãos regulamentadores 9,10,11 . Propostas de vigilância de indicadores estão ocorrendo, analisando os impactos antropogênicos para a qualidade da água e fazendo alertas sobre as consequências a médio e longo prazo da falta de cuidado com esse recurso natural 12,13,14 .…”