At times, washing something can actually make it dirtier. And when that something is food, it puts the public’s health at risk.
In Hawai`i, tens of thousands of acres of agricultural land are irrigated with water from open ditches, which, because of ungulates and the nature of tropical soils, can contain high levels of fecal bacteria. About 16,000 of those acres are used to grow fruits and vegetables. And at some of these farms, packing is done in the field and ditch water is used to wash the produce before it is sent to market.
But which farms are using dirty water to wash their crops? That sticky question is what the Agribusiness Development Corporation hopes to answer. At its March 1 meeting, after hearing a presentation on food safety from a University of Hawai`i researcher and state Department of Agriculture officials, the ADC board approved a request by its staff to underwrite a study to assess how many farmers use non-potable water to wash their produce.
The ADC manages some of the largest ditch systems in the state, including the Waiahole system on O`ahu and the Kekaha system on Kaua`i. Given this, the board was concerned about minimizing the potential for E. coli or salmonella contamination of local produce by irrigation water. E. coli can cause severe diarrhea or cramps, or, in the worst case, hemolytic uremic syndrome, which can lead to kidney failure and death. Last year, consumers nationwide were put on alert when spinach contaminated with E. coli sickened more than 100 people across 21 states. A November 2006 report by Aurora Saulo, an extension specialist in food technology with the University of Hawai`i’s Department of Tropical Plant and Soil Sciences, states, “From what we know today, disease-causing bacteria such as Salmonella, Campylobacter jejuni, vibrio cholerae, and E. coli O157:H7 are more likely found in fresh produce due to contamination through raw or improperly composted manure, irrigation water containing untreated sewage, and contaminated wash water.”
On average, between 2001 and 2005, the state Department of Health documented about 18 E. coli O157:H7 infections a year and about 304 cases of salmonella poisoning a year out of a resident population of about 1.25 million. Whether any of those cases were the result of contaminated produce is unknown. Even so, James Hollyer, an economist with the university’s College of Tropical Agriculture and Human Resources, has been working to reduce that risk. At the ADC meeting, Hollyer gave a presentation on an experiment completed last year to reduce E. coli levels in irrigation water at a farm in Kula, Maui.
With a $30,000 grant to CTAHR from the ADC, Hollyer, who has been working on farm food safety issues for the past six years, helped install a solar water pasteurizer developed by Safe Water Systems, a Honolulu company. The farm used less than 500 gallons a day and had a number of goats that contributed to high E. coli levels – 29 parts per million – in the irrigation/wash water, Hollyer said. He added that he was not worried about the water used in drip irrigation as much as he was about the water being used to wash produce during field packing.
Federal Food and Drug Administration guidelines recommend that processing water meet drinking water standards set by the Environmental Protection Agency or similar high standards. The EPA’s maximum contaminant level for E. coli in drinking water is zero parts per million. Using the solar pasteurizer, Hollyer was able to reduce the E. coli at the Kula farm to below detectable levels.
“It’s a good alternative technology to chlorine, ozone, or other systems,” he said. It’s also cheaper: It cost $20,000, compared to a chlorine-based system, which can cost as much as $50,000, he said. Although the system has been used worldwide to purify drinking water in remote areas, it had never been used for irrigation water. “We put a new technology on the map,” he said.
According to Albert Louie, a food safety auditor with the Hawai`i Department of Agriculture, an E. coli count of 29 ppm could shut a farm down. The department, he said, is working to determine how many farms have similar levels.
Since the late 1990s, both the government and private industry have been pushing for better food safety via various certification programs. About a year after the FDA published a Guide to Minimize Food Safety Hazards for Fresh Fruits and Vegetables in October 1998, Safeway announced it would only buy produce from food safety-certified farms. That pledge, however, made it impossible for Safeway to purchase locally grown produce, so eventually it backed away from that standard.
In response to Safeway’s initial announcement, the state DOA developed its own food safety auditing service. Using standards adapted from those used by its New Jersey counterpart, the Hawai`i DOA discovered a few areas of concern: non-potable water being used to wash produce, portable toilets and handwashing facilities not being available for field workers, a lack of education on food safety (especially for immigrant workers), and poor record-keeping.
Although Safeway no longer requires food safety certification from local growers, other retailers, including Costco, demand it. Several food safety auditors work in Hawai`i: the American Institute of Baking, Davis Fresh, Primuslab.com, and the U.S. Department of Agriculture, among others. And they do all kinds of audits, including audits of farms, crew, greenhouses, wholesale distribution centers, cooling/cold storage, packing houses, and processing plants.
Despite the abundance of auditing options, the question of how many farmers use substandard water to wash their produce remains. The DOH, which also monitors food safety, has not issued many food recalls and has “kept quiet,” Louie said.
“We don’t know how big the problem is. We need to do a survey of produce farmers and water users. It will cost a few thousand dollars to do,” said ADC executive director Alfredo Lee.
Hollyer noted that the subject presents an uncomfortable situation. Asking a farmer whether he is using dirty water is like asking a man if he beats his wife; it’s not something he’s likely to openly discuss, Hollyer said.
ADC board member Wayne Katayama suggested that rather than ask that sensitive question, the board should try to make the pasteurization technology more readily available to farmers. “Focus on technology rather than names. I would hate to do that,” he said.
ADC board chair Teena Rasmussen, however, supported the survey and suggested that produce houses be included.
“Collecting the data is going to be very difficult. When there was an amnesty program for leftover chemicals on farms, everybody thought it was a trap,” she said. As an example of farmers’ reluctance to come forward with problems, Louie referred to the anthurium blight. Although nearly every grower had it, he said, only a small number of farmers owned up to it.
Despite the obstacles, the ADC board voted to provide $7,500 to Hollyer to conduct the survey.
— Teresa Dawson
Volume 17, Number 12 June 2007
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