There's a reason why organic food sickens far more people than conventional produce; a lack of science in agricultural practices.
Researchers have identified some agricultural management practices in the field that can either boost or reduce the risk of contamination in produce from two major foodborne pathogens: salmonella, the biggest single killer among the foodborne microbes, and Listeria monocytogenes.
Foodborne illness kills around 1,300 people annually in the US, according to the Centers for Disease Control and Prevention. Produce accounts for nearly half the illnesses and 23 percent of the deaths. But those illnesses and deaths could be reduced without any costs to growers, the research found. For salmonella, manure application within the year prior to the researchers' sampling boosted the odds of a contaminated field, while the presence of a buffer zone between the fields and potential pathogen reservoirs such as livestock operations or waterways was protective.
Irrigation within three days before sample collection raised the risk of listeria contamination six-fold. Soil cultivation within the week before sampling also increased the chances of contamination.
"This is going to help make produce safer," says Laura Strawn, a Cornell researcher on the study. "We could significantly reduce risk of contamination through changes that occur a few days before the harvest. These findings will assist growers in evaluating their current on-farm food safety plans (e.g. "Good Agricultural Practices"), implementing preventive controls that reduce the risk of pre-harvest contamination, and making more informed decisions related to field practices prior to harvest. Small changes in how produce is grown and managed could result in a large reduction of food safety risks."
Citation: Laura K. Strawn, Yrjo T. Gröhn, Steven Warchocki, Randy W. Worobo, Elizabeth A. Bihn, and Martin Wiedmann, 'Risk Factors Associated with Salmonella and Listeria monocytogenes Contamination of Produce Fields' ,Applied and Environmental Microbiology, 27 September 2013 doi:10.1128/AEM.02831-13