There is increasing interest in methodologies for the simultaneous concentration and detection of multiple targets in individual samples. The aim of this study was to investigate the potential presence of E. coli DNA in beef extract powder used as part of a procedure to concentrate water samples for the simultaneous detection of bacteria, viruses and protozoa. DNA from E. coli was detected in five out of six beef extract lots tested, demonstrating the limitations of its inclusion when being used in assays that will be used for the detection of E. coli in water samples. Further work is required to clarify if this phenomenon also occurs for other microorganisms of interest in water.Water used in the production and preparation of vegetables can be sourced from public supply systems, groundwater, recovered rain water, surface water from lakes, rivers or artificial ponds, or even treated wastewater in some countries (Allende and Monaghan, 2015;Jongman and Korsten, 2018;Uyttendaele et al., 2015). The microbial quality of different water sources, especially surface and treated wastewaters is of crucial importance, given the potential for pathogenic microorganisms present in the water to persist and be transferred to plant material. Several fresh produce related microbial disease outbreaks have been attributed to the use of contaminated water at different steps of the farm-to-fork chain, as exemplified by an outbreak in the United States caused by the consumption of raspberries contaminated with Cyclospora present in the water used for pesticide application (Herwaldt et al., 1997), an outbreak in Finland caused by the consumption of frozen raspberries contaminated with Norovirus during irrigation or water spraying before cooling (Ponka et al., 1999), an outbreak attributed to the consumption of spinach leaves contaminated with Escherichia coli O157, in the United States, caused by the use of water contaminated by cattle (Parker et al., 2012;Sharapov et al., 2016), or an outbreak of Salmonella Saintpaul infections in the United States related with the consumption of jalapeno or serrano peppers contaminated with farm water (Barton Behravesh et al., 2011). Ensuring the microbiological quality of the water used in the production of fresh crops is therefore of vital importance for both consumers and food business operators.Guidelines and regulations for the microbiological quality of water used for the production of crops focus on indicator microorganisms, typically referring to the presence and/or quantification of E. coli and faecal or total coliforms as criteria for microbial quality of the irrigation water (Uyttendaele et al., 2015). In Europe, the quality of water used for crop production is regulated by Regulation (EC) 852/2004 on the hygiene of foodstuffs, stating that food business operators producing or harvesting plant products should use potable water or clean water whenever necessary to prevent contamination (European Commission, 2004). The definition of potable water is outlined in EC Regulation 98/ 83/EC on the...