Escherichia colisurvival in lettuce fields following its introduction through different irrigation systems

Abstract

Aims: This study aimed to assess the contamination risk of Escherichia coli in commercial lettuce grown under three different irrigation systems (overhead sprinkler, subsurface drip and surface furrow). Methods and Results: Three replicated field trials were conducted. In an initial trial, we consistently observed higher mesophilic bacteria counts under sprinkler irrigation but visual quality was found to be dependent on the water potential of leaves at harvest. Further, in the other two trials, E. coli K‐12 strains LMM1010 and ATCC 25253, was injected into the water stream of the different irrigation systems to determine survival in the field. Results showed that product samples were positive for E. coli up to 7 days when using sprinkler irrigation, whereas only one product sample was found positive for E. coli when using other irrigation methods. Survival of bacteria in soil persisted longer in furrow‐irrigated areas, ranging from an estimated 17 days in winter months to 5 days during the warmer summer periods. This finding combined with results from a parallel 3‐year survey of canal waters indicate that while highest risk of finding E. coli in irrigation water is in warmer months, the survival in soil is lower during the same time period. Conclusions: Our results in a study set under common commercial conditions confirmed the enhanced risk of E. coli contamination when using sprinkle irrigation. Furthermore, E. coli persistence in furrow‐irrigated soil validates the importance of an early irrigation termination for both sprinkler and furrow methods. Significance and Impact of the Study: Stringent monitoring and in‐field food safety controls should be emphasized during the last few days before harvest.

Risk Factors Associated with Salmonella and Listeria monocytogenes Contamination of Produce Fields

“…Water has been iden-tified as a major reservoir for pathogens and irrigation as a vehicle for transmission of pathogens to fields and produce (12,30,41,(72)(73)(74)(75). L. monocytogenes is often found in various water sources, with reported prevalence from Ͻ1% to 29% (14,76,77).…”

Survival of Enteric Pathogens During Butterhead Lettuce Growth: Crop Stage, Leaf Age, and Irrigation

“…Irrigation water is considered a potentially important introduction route, and several studies have shown its potential for the transmission of enteric pathogens to lettuce plants. However, most of these studies were conducted either under laboratory or controlled conditions in growth chambers (Brandl and Mandrell, 2002;Solomon et al, 2003;Aruscavage et al, 2008;Aruscavage et al, 2010;Brandl and Amundson, 2008;Zhang et al, 2009;Erickson et al, 2010a) or field experiments (Barker-Reid et al, 2009;Erickson et al, 2010b;Harapas et al, 2010;Wood et al, 2010;Fonseca et al, 2011). Few studies have compared both types of experimental setups.…”

Análise química e bacteriológica da água de irrigação utilizada na Comunidade Agrícola Nova Esperança, Manaus - AM.

“…Em áreas de produção agrícola, destacam-se como fatores que reduzem a qualidade das águas superficiais e subterrâneas, o cultivo e manejo do solo e o uso sucessivo de agrotóxicos, fertilizantes, despejos residuais urbanos e industriais e adubos orgânicos, que causam acúmulo de metais potencialmente tóxicos (MPT) e contaminação bacteriológica por (coliformes totais e fecais) nos ecossistemas aquáticos e terrestres (CHEN et al, 2006;FONSECA et al, 2011;HANI;PAZIRA, 2011).…”

“…O aumento considerável do número de patógenos nos corpos hídricos na área de produção agrícola ocorre principalmente pelo escoamento de esgotos domésticos e sistemas sépticos, como fossas, ricas em excretas humanas ou pela ação das chuvas (CRAUN et al, 2010;FONSECA et al, 2011).…”