It’s berry season.  Time for some chlorine.  

No, we’re not talking about chlorine as in sunglasses and swimming pools but rather chlorine as in berry farmers and irrigation water.

And while the juxtaposition of swimming and irrigation water may at first seem far-fetched, the generally accepted food safety standard for irrigation water for crops such as berries that are eaten raw is based on the federal Environmental Protection Agency’s water-quality standard for recreational swimming water.  

That standard, which is directed at recreational waters such as beaches, rivers and lakes, is calculated on full-body contact at swimming areas impacted by human sewage.  

Until the federal government comes up with an actual standard for irrigation water–as is expected to happen during the rulemaking following the passage of food safety legislation now before Congress–the industry is using the EPA standard as a starting point, according to the report, “Standards for Irrigation and Foliar Contact Water (pdf),” by Trevor Suslow, Extension research specialist in post-harvest quality and safety, at the University of California, Davis.  

Complying with the EPA standard is still voluntary, although growers who want to gain certification under Good Agricultural Practices (GAPs) must show that their irrigation water is free from pathogens that could get people sick.  For the most part, distributors selling to retail grocery chains require GAP certification.

For consumers, this added scrutiny on irrigation water is good news because it represents yet another example of how seriously growers, packers, and retailers are taking the need to have food safety practices in place–starting at the farm and extending all of the way up to where the food is ultimately purchased by the consumer.  

Oregon berry grower and packer Mark Hurst, co-owner of Hurst’s Berry Farm, the leading fresh-berry shipper in the Northwest, told Food Safety News that berry packers in his area are increasingly requiring berry growers who rely on water sources that don’t meet certain standards to chlorinate the water as a way to protect consumers from foodborne illnesses.

While this isn’t true across the board, Hurst said that it’s becoming more and more common in places where growers rely on rivers, streams, and lakes that are contaminated to irrigate their crops.

Generally, surface-water contamination comes from livestock, but also from humans and wildlife. Pathogens in the water can include  E. coli, Salmonella, Listeria, or Cryptosporidium, all of which can sicken or kill people.

In contrast, growers who rely on deep wells for irrigation generally don’t run into the same problems, although that’s not a given.

According to a report from the University of Florida, “Treating Irrigation Systems with Chlorine 1,”  irrigation systems can become partially or completely clogged from biological growths of bacteria or algae, which are often present in surface water and ground water.

The report also points to chlorination as a chemical method for removing microbial growth.

Chlorine quickly dissipates after application, which means that consumers don’t need to worry about its use in irrigation water.

On the food safety front, clean, safe irrigation water is a critical issue, especially for crops such as fresh-market berries that are eaten raw because there’s no “kill step” to get rid of the pathogens as there is for food that’s cooked before it’s eaten.  High temperatures kill most pathogens that can get people sick.

“From a food safety standpoint, it’s a risk for the retailer,” Hurst said, referring to contaminated irrigation water. “Packers who want to supply major retailers will have to make sure their growers are using safe irrigation water. It’s another way to reduce risks.”

Even so, some berry  growers, and even some berry packers, are still unaware of this heightened scrutiny on irrigation water.

As far as Hurst is concerned, they need to “get their heads out of the sand” on this one.

“If you’re depending on a river for your irrigation water, you’ve probably got problems,” he said.

Tom Walters, Small Fruit Horticulturist at the Washington State University research center near Mount Vernon, Wash., agrees with Hurst that growers will increasingly see more demands on the part of the packers to chlorinate their irrigation water if testing shows it contains pathogens.  

He also agrees with Hurst that growers who aren’t up to speed on the added scrutiny on irrigation water need to get their heads out of the sand.

“It’s definitely a concern for buyers of food that doesn’t get cooked,” he said. “They (packers and retailers) are all very concerned about food safety and are looking at all possible sources of fecal coliform and E. coli. One of the things they want to know is what the source of the irrigation water is.”

Walters also said that he knows of one national distributor of fresh berries that’s asking growers to take samples from their irrigation lines instead of from the source of their irrigation water.

Growers associations are also “very keen at looking at irrigation water,” Walters said.

That’s not surprising, said Tom Amrhein of Naturipe Farms, pointing out that no grower, packer, or retailer can afford to have a problem with foodborne illnesses.

“It could destroy an entire industry,” he said.  

That became apparent in the 2006 E. coli outbreak in spinach in California.  During the investigation, the California Department of Health Services and the federal FDA identified contaminated irrigation water as a possible source of E. coli O157:H7. Even though that link with irrigation water was never confirmed, the outbreak did lead to increased concerns about  irrigation water.

The spinach outbreak scared consumers. In the marketplace, consumption of packed spinach fell to 43 percent of previous levels, with devastating economic losses to the entire spinach industry, according to Suslow’s report.

Yet this economic havoc was triggered by what was thought to be a single contamination event in a single spinach field.

Oregon berry grower Hurst has a similar story involving irrigation water to tell: the large foodborne illness outbreak in 1996 linked to Guatemalan raspberries contaminated with the parasite Cyclospora.  

Hurst said that even today–despite Guatemala’s strict food safety standards developed as a result of that outbreak–Guatemala’s berries are still on “the black list” when it comes to consumer perception.

“No one wants to see that happen here,” he said. “We can’t afford to let it happen.”

Greg Komar, Director of Food Safety at Growers Express in the San Francisco Bay Area, would agree, pointing out that “when one operator has a problem all operators that deal with that commodity will have a problem.”  

That’s why he thinks everyone involved  in the production of a commodity needs to make decisions based on what is best for the industry as a whole as oppo
sed to the individual. He refers to that approach as “the largest common denominator.”

“From a purely commodity-specific perspective, I do not know of a fresh produce item that, if the water source was confirmed to be a concern, would not use some type of mitigation step–such as chlorination–to reduce the concern,” he said.  

When asked about the cost of chlorinating irrigation water, Komar  pointed out that chlorine sold as sodium hypochlorite (common household bleach) tends to cost less per volume than other commonly used sanitizers.

WSU horticulturist Walters said that in most cases, chlorinating an irrigation system isn’t all that expensive or “a huge bother.”  

Cindy Jewell, director of Marketing for California Giant Berry Farms, said that her company requires growers to test their water two times yearly as part of a food safety program, which she refers to as “common practice in the industry.”

She also said that growers who have issues with test results  might consider chlorination as a way to resolve the problem.

But the company does not make recommendations about whether or not to use chlorine.  Instead, it simply requires its growers to pass food safety testing provided by a third-party auditor.

She also said that chlorination of irrigation systems is not unique to the California or the berry industry.  

“The important thing to note,” she said, “is that growers are very conscious about water quality and all other cultural practices and take steps to address issues that could negatively impact their products and the consumer. Ultimately, they want to do the right thing to ensure a safe and wholesome product.”

At the Watsomville Berry Co-op in California, all of the co-op members rely on deep wells.  

“They have to show that they have good irrigation water,,” said Tom Simmons, general manager of the co-op.   

The same is true for Naturipe.  Amrhein said the first thing the company does when approached by a grower is to check the irrigation water.

“If there are problems, we won’t take his fruit,” he said.

In Washington state, Jason Kelly, spokesman for the state’s Agriculture Department, said that under USDA Good Agricultural Practices/Good Handling Practices, agricultural operations must perform a water-quality assessment to determine the quality of water they are using for irrigation and processing.

To date, USDA has not required any irrigation water to be treated with chlorine, he said. However, the audits are voluntary and the audit standards for each operation can be tailored to meet their specific needs, including the use of chlorination to minimize the risk of microbial contamination of the product.   

Keith Refsnider, director of Food Safety at Driscoll’s, and Dr. David Gombas, senior vice president of Food Safety for United Fresh, declined to be interviewed for this article.