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‘Root Cause’ Likely to Call Attention to Farming Practices

It was one month ago today that Colorado named its own “Rocky Ford-brand” cantaloupes as the likely source of a multistate outbreak of Listeria infection, which now could easily become the most deadly food poisoning in modern U.S. history.

With 112 sickened in 25 states and 23 mostly elderly Americans killed, the federal government’s report on its investigation into the cause of the Listeria contamination is said to be only a few days away.   

Jensen Farms, the grower that recalled at least 1.5 million “Rocky Ford-brand” cantaloupes two days after that first public health warning went out, and other Colorado cantaloupe growers are anxiously waiting for that report.

When the “root cause” — how deadly Listeria got into the cantaloupes — is identified by that report, it may then focus attention on harvest or post harvest practices and may even point to places where it is safer to grow cantaloupes than other places.

Specifically, it may be safer to grow “dry” cantaloupes in places like California than “wet” cantaloupes grown in more inland climes. Not even California cantaloupe growers have said that yet — although they come pretty close.

The distinction is whether cantaloupes are grown in such dry conditions that they can be field-packed, as is common in California, or whether they are grown where they need a bath before they are shipped, meaning they are shed-packed.   

Colorado’s major cantaloupe shippers, including Jensen Farms, do shed packing, according to Colorado State University’s Lawrence (Larry) Goodridge, a food microbiologist in the department of animal sciences. He says some small growers pack directly into bins in the fields.

While focused on Jensen Farms, the investigation by the U.S. Food and Drug Administration, federal Centers for Disease Control and Prevention, and state health agencies will bring attention to all cantaloupe growers in the Arkansas River Valley.

Most of those are wondering if and when they will be able to recover from having Rocky Ford cantaloupes associated with the deadly outbreak.

The findings will turn the spotlight on differences in the way cantaloupes and other melons are handled during and immediately after harvest. The one entity putting out a lot of information on this subject is the California Cantaloupe Advisory Board, which claims that California-grown cantaloupes have never been associated with a foodborne illness outbreak.

Jim Prevor, who writes about the produce industry as the “Perishable Pundit,” puts it this way:

“What the California cantaloupe industry found was that one should not wash a cantaloupe. That moisture itself is the enemy of safety. California packers, who were proud of their wash systems, shut them off.”

In four videos produced to educate both consumers and growers, the industry advisory board demonstrates both the field- and shed-packed methods of handling cantaloupes.  

While offering the opinion that either method can be safe if done right, field packing is depicted as both simple and safe. By contrast, shed packing comes across as complicated with all kinds of possibilities for cross contamination once equipment gets contaminated as it did at Jensen Farms.

The equipment used in shed packing can involve simple washes or sprays to clean cantaloupes before they are packed or they can involve more complete sorting and grading systems.   

Growers who do shed packing are not afraid to get melons wet, while growers who do field packing go out of their way to keep their melons dry.  

“A strong word of caution, however, in some cases using water on a melon contact surface meant to remove dirt can make things worse,” says one of the training films.  “In hard-to-clean, hard-to-reach places, water, melon juice and residues at warm air temperatures can combine to make a perfect breeding ground for bacteria.”

California cantaloupes are grown in neat rows keeping the melons above the irrigation water and keeping them clean and dry until field workers put them in a box and send them off to the cooler.

Colorado cantaloupes are harvested from the matted ground growth were they grew before they are collected and sent off for shed packing.

The question — no matter what the root cause turns out to be — is whether the harvest and post harvest practices made the contamination situation worse.    

By boxing in the field, California growers point out that if a melon was contaminated, it would cross-contaminate others in the same box. 

Packing sheds are complicated places. Melons are graded, sorted, sized, washed, cooled packed, and placed on pallets.  It is possible one cantaloupe going through shed packing might come into contact with dozens or even hundreds of others.

To come up with the root cause of the contamination, investigators will have to eliminate many other possibilities, Including domestic animals and wildlife feces, pest infestations, weather, melon rind surfaces, melon-to-ground contact, mechanical damage, melon wetting and brushing, and water quality of the cold water or topping ice used to cool melons.

While potential root causes are many, only one is getting much attention in the Colorado cantaloupe-growing area. A biosolids company that has sprayed fields in the vicinity is a Denver television station’s favorite suspect. The biosolids, which are used as fertilizers, originated with treated sewage from New York State.

This seems to be the one possible culprit that people know about. A woman who identified herself as Maxine called into Colorado Gov. John Hickenlooper’s monthly radio show, asking: “Are we going to continue to have sewage coming into our state and ruin the Rocky Ford cantaloupe business?”

Hickenlooper said while it is not known for certain yet, he doubts there was Listeria in the biosolids. He also agreed with growers in the immediate area around the town of Holly Ford that the Rocky Ford brand does not extend almost 100 miles to the east to include Jensen Farms.

But prior to the outbreak, there is no record of anyone objecting to Jensen Farms marketing its cantaloupes under the “Rocky Ford” brand.

© Food Safety News
  • kwarriner

    The melon industry need to adopt the decontamination methods such as hot water, steam or UV:peroxide. There is scientific evidence that all three are effective at decontaminating surfaces of cantaloupes. Contamination is typically acquired in the field and so I doubt a field packed product would be safer than fruit transferred to a packing house. Decontamination techniques are key as with any fresh produce

  • Susan Coulter, DVM

    I’m glad someone is looking at holding/shipping practices for the contaminated cantaloupes. Since Listeria grows at cool temperatures it seems it would be unlikely to grow in the very hot fields in Holly, Colorado. However, if they are washed and not dried, and then held and shipped at cool temperatures in Listeria’s comfort zone it would be very easy to understand how this could happen. I feel very sorry for this poor farmer and everyone in the small town of Holly. They are probably looking for answers and only getting blasted with all the blame.

  • Well written thoughtful look at the differences in cantaloupe handling.
    Dr. Coulter, I don’t think I’ve read anyone blast the cantaloupe farmer. The lawyers have sued the farmer, but that’s what lawyers do.
    People want to know what caused this outbreak, but most of the critical concern is about whether surrounding large animal operations may have contaminated water sources used with the cantaloupes.
    We’re all intensely interested in this report.

  • As we can see with every outbreak that’s happened to find the root cause takes a long time and is not easy to pinpoint or eliminate. In the meantime contaminated product is still reaching the market and consumer due lacking an effective traceback system. The PTI/GS1 barcode only points to the brand name in this case Jensen Farms, if they even had a GTIN number. The second part of the GTIN code is the product code to ring up a few cash registers in some big box stores. 95% of the retailers can’t use this code anyway, as they have to buy all new expensive readers. It does nothing for traceback to the field or spot in the field or any handling area or person that handled the product in between.
    ScoringAg has the only traceback and traceup system that goes from the spot in the field through the whole supply chain, raw, commingled or processed, where the producer and handler keep all the GAP’s BMP’s, records without any extra charge. The contaminated cantaloupes they ended up in fruit cups a few days ago, because no body was aware of and informed, proofs there is no effective traceup system used. To have a trace from the packer to the distributor is not enough and doesn’t work as we can see again. The bad part is people are getting sick and die for weeks and everybody is only talking about the root cause and not how to find the contaminated product in the supply chain or consumers kitchen. With an SSI-EID code on every sticker it would be an easy and inexpensive way to do it in seconds, as there is a search engine in http://www.ScoringAg.com or http://www.Traceback.com. Enter this code SSI_06E238C1F2 into Search SSI-EID on one of these websites and you will see how long it takes to pinpoint the source of this fruit. In the uploaded document files, that can only be seen by the account owner, there are all certifications, water tests and farming practices. Every fruit is stickered with an SSI-EID code. If one of the fruits from this part of a grove would be contaminated it’s easy for the farmer to find the problem. No guessing and researching for weeks or months.
    What is the price for a sticker compared with the recall cost and the cost for lawsuits? How much longer can the industry especially the retailers afford it buying products without an SSI-EID traceback code?

  • Keith Warriner

    The melon industry need to adopt the decontamination methods such as hot water, steam or UV:peroxide. There is scientific evidence that all three are effective at decontaminating surfaces of cantaloupes. Contamination is typically acquired in the field and so I doubt a field packed product would be safer than fruit transferred to a packing house. Decontamination techniques are key as with any fresh produce

  • jmunsell

    Shelley Powers properly states that people want to know what caused this outbreak, and wonders if surrounding large animal operations may have contaminated water used on the canteloupe fields. I fully agree. I am greatly interested in knowing where & how listeria originate. Two other bacteria, e.coli & salmonella, are “enteric” bacteria, meaning they emanate from within animals’ intestines, and proliferate on manure-covered hides. Listeria are not “enteric” bacteria. So, exactly where does it originate? Many news articles suggest the possibility of animal waste being the source of listeria-laced canteloupe. If true, does this mean that listeria originate from livestock, just like “enteric” bacteria? If listeria is found in the irrigation water feeding the canteloupe fields, do you agree that we need to go upstream and find the source of the listeria? John Munsell

  • So if there is a system on the market as described in the comments above, http://www.scoringag, why is the industry not using it in order not only to save money but, also people’s health and life?
    In my opinion the lawyers have to look into if this wouldn’t be considered a case of manslaughter? Or at the very least negligence.
    It’s like building a car and delivering it without functional brakes.
    By entering the SSI-EID number I was able to see the records from the grower and the agricultural practices used on the farm.

  • mattj

    Someone needs to develop a smooth-surface cantaloupe.

  • John Munsell

    Shelley Powers properly states that people want to know what caused this outbreak, and wonders if surrounding large animal operations may have contaminated water used on the canteloupe fields. I fully agree. I am greatly interested in knowing where & how listeria originate. Two other bacteria, e.coli & salmonella, are “enteric” bacteria, meaning they emanate from within animals’ intestines, and proliferate on manure-covered hides. Listeria are not “enteric” bacteria. So, exactly where does it originate? Many news articles suggest the possibility of animal waste being the source of listeria-laced canteloupe. If true, does this mean that listeria originate from livestock, just like “enteric” bacteria? If listeria is found in the irrigation water feeding the canteloupe fields, do you agree that we need to go upstream and find the source of the listeria? John Munsell

  • Anthony Boutard

    I grow muskmelons and I think the role of the corky surface in food safety is over-stated. There is another unique quality muskmelons have that is probably of greater significance.
    In the muskmelon, which sold as cantaloup in the United States, the attachment between the stem and the fruit gets weak as the fruit ripens. The disk-like attachment slips with a bit of pressure, opening up the fruit’s vascular tissue. Muskmelons are harvested at slip, whereas other fruits in the cucumber family are usually cut from the plant. You can see the green disk on the top of the fruit where the stem slipped away. In winter squash, if the disk is accidentally slipped, the fruit will spoil in days or weeks, while a fruit cut at the stem will last for months.
    Bear in mind, the tissue inside the muskmelon fruit has a high sugar concentration, between 14 and 20 degrees brix. Growers shut off the irrigation as the fruit ripens to increase the sugar concentration. When melons are put in a bath of water, osmosis will naturally draw in the outside water, especially during the time immediately after harvest. We need to test and see whether Listeria and Salmonella can enter the melon through this vascular tissue, and whether the low acid melon tissue provides a culture medium for these bacteria.
    On our farm, we clean melons gently with a terry cloth towel, and never wash them, because of my concerns about this disk of exposed vascular tissue. We roll the melons over to make sure they fully dry in the sun. The UV spectrum in sunlight is a very effective against bacteria such as Listeria. I suspect field packed melons are safest option if care is taken at that step.
    Post harvest disinfectants should never substitute for careful harvesting and, if the interior tissues of the fruit are contaminated, they are worthless. Also, mistakes can happen in the disinfection step.
    Anthony Boutard
    Ayers Creek Farm

  • Pamela Sweeten

    This other variety is well and good however traceback is mandated by FSMA. How will you comply?
    One up one down DOES NOT work! Complete traceability is The ONLY way!
    http://www.ScoringAg.com offers this.