When it comes to best practices for produce growing and retailing, some of the latest water use recommendations sound like advice often heard from veteran hikers and campers on hydration safety.
The safest water comes from a municipal treatment plant. Indiana’s groundwater retrieved from its wells is almost always as good but, technically, it is slightly iffier.
Surface water must always be considered suspect because it may be contaminated. It is safest in most cases to use it only after it has been treated.
For these reasons, about 10 Allen County growers directly involved in produce sales were advised during recent Purdue University Cooperative Extension Service food safety training to depart from tradition and refrain from washing their vegetables and fruits, especially cantaloupe, because of the crevices on its surface.
Some of the growers at the March 27 event sell through area farmers’ markets and roadside stands. Some of them supply area restaurants and food retailers with fresh local produce.
“Everybody washes their produce after they harvest it and for a time everyone recommended: Wash produce,” said James Wolff, an agriculture and natural resources educator with Purdue’s extension office in Allen County.
“Now, Cornell, Purdue and other institutions are actually recommending you don’t wash produce after you harvest it and before you sell it, because that washing stage can be an increased risk of contamination of that produce.”
“If your water is contaminated or if, depending on your wash process, you have one piece of produce that’s contaminated, it can contaminate the other things,” he said. “You’re just trying to reduce the contamination by eliminating that step.”
Typical Americans consume 274 pounds of fresh fruits and vegetables each year, and only rarely get sick from what they eat. Because it still happens, food safety experts advise that everyone from the farmer to the consumer plays a role in food borne illness risk reduction.
For produce washing, “the chances are at home the water source is a little bit safer than if you’re doing it on the farm,” Wolff said.
“City water generally has low contamination issues,” he said. “And yes, I know. You go to the market with dirty carrots, and people probably aren’t going to buy them as much.
“But, at some point maybe in your talking with them, if you help them understand why you didn’t wash the carrots and help them understand that that is trying to make sure you’re getting safe produce to them, they might understand a little bit better.”
Northeast Indiana gets enough rainfall most growing seasons to keep its major crops sufficiently watered. But, if a vegetable patch needs more, and city or well water is not available, a surface water irrigation system that drips near plants is a better practice than one that sprays over plants, Wolff said.
Surface water should be tested annually before it is used, and during its use it should be tested at least monthly. Even well water should be tested annually. And produce growers on city water should obtain copies each year of results from the testing it undergoes.
All water that contacts the crop after harvest must meet Environmental Protection Agency standards for the microbial quality of drinking water at the start of any processing. If the water does not meet those standards, it can be treated with a sanitizer to bring it into compliance.
The 2011 Food Safety Modernization Act, which became law last year, established water testing requirements for operations that sell more than $25,000 of produce annually. Compliance deadlines vary, based on sales volume, with the smallest farms covered by the act receiving the most time.
Even when best practices are followed by growers, consumers and others handling the produce they buy, eating the food uncooked is never without some risk.
Results of a study Purdue released to the general public on March 29 show the bacteria Listeria monocytogenes can live inside romaine lettuce tissue during every stage of the plant’s growth process.
The findings recently were presented in the April edition of the Journal of Food Protection. They suggest the potentially lethal pathogen may not be killed off by conventional post-harvest sanitizing practices.
The bacteria is naturally found in common soil that has not come in contact with contaminants, said Amanda Deering, a clinical assistant professor in Purdue’s food science department, who led the research.
Even as a seed first imbibes water to grow, “the bacteria gets sucked in with it,” Deering said. “There’s not much we can do when it’s naturally present.”
“We don’t know how often this actually happens in the field, but do know it can happen,” she said. And for Deering, knowing this makes it even more important for everyone handling produce to control what they can in order to reduce food borne illness risk.
“It helps us think about good agricultural practices,” she said.
In addition to the annual testing of well water, best practices call for good groundwater protection by properly retiring and capping abandoned or unused wells, and by avoiding the mixing of pesticides or other chemicals near wells.