Tuesday, October 6, 2009

Free-Range, Organic, Air-chilled Poultry: Does Salmonella Care?

October 6, 2009

One of the stops we made at the San Francisco Farmer's Market last month was Aimee's Mountain Ranch Kitchen, where we learned the following about the Certified Organic poultry on display.

Last Thanksgiving, my husband and I opted for a locally raised free-range turkey in place of the our usual supermarket bird. I have to report that, while the local bird was tasty, it also was one of the toughest, boniest turkeys we had ever roasted. I guess you have to be tough to thrive in Vermont!

Although Aimee's Mountain Ranch Kitchen does not claim that its Certified Organic, free-range, air-chilled chickens are microbiologically safer than conventional birds, some people believe that poultry raised and processed under these conditions is less likely to contain pathogens, notably, Salmonella and Campylobacter. Unfortunately, this is not so.

In 2005, researchers at the University of Maryland found that 76% of organic chickens and 74% of conventionally raised chickens available in retail stores contained Campylobacter. Salmonella was found in 61% of the organically raised chickens and 44% of the conventional birds. Similarly, in a University of Louisiana study, Salmonella was recovered from 22% of conventional chicken carcasses in the Baton Rouge area and from 21% of organically raised chicken carcasses.

What about free-range vs. cage-reared birds? Don't count on seeing any microbiological benefit here, either. Studies in the United States and Great Britain have shown that free-range birds are just as contaminated as cage-reared poultry.

Then, is chilling poultry carcasses in air any safer than by immersing them in cold water? Air-chilling sounds as though it would be less likely to foster the transfer of Salmonella and Campylobacter from a few contaminated birds to an entire batch of "clean" carcasses. But research studies published in 2003 and 2007 failed to substantiate this.

Nevertheless, there are some benefits to free-range, organic farming and air-chilling of poultry carcasses.
  • Water-chilling often results in 8-12% water (by weight) being retained by a carcass, according to USDA. This "retained water" must be declared on the label. Air-chilling eliminates the extraneous water that otherwise is added to poultry carcasses – water that the consumer pays for, since poultry is sold by weight.
  • While conventional and organically raised poultry don't differ significantly in their level of Salmonella contamination, the University of Louisiana study (mentioned above) found that Salmonella recovered from conventionally raised birds was far more likely to be antibiotic-resistant.
  • Air-chilling reduces the amount of water used by poultry processors – a serious concern in drought-prone areas.

Because free-range and organic farming are more labor-intensive than conventional large-scale industrial farming, organic and free-range chicken tends to be more expensive. Whether the outcome of these artisan farming procedures is worth the added cost is a judgment that each consumer has to make.

Whether you decide to buy a conventionally raised chicken or a free-range, organic bird, remember to handle the carcass as though it contains Salmonella and Campylobacter.
  • Cook the chicken to an internal temperature of 165ºF, using a meat thermometer to verify the temperature;
  • Clean and disinfect all kitchen implements, cutting boards and counter tops that may have come into contact with the raw chicken;
  • Wash your hands thoroughly after handling raw chicken; and
  • Sanitize wet sponges and dishrags by microwaving them on the highest setting for at least 30 seconds.


  1. Another top safety tip for handling chicken in the kitchen. Use wood cutting boards. Studies have shown that plastic cutting boards, with their cracks and crevices from use, encourage bacteria growth. Another study showed that people who use plastic or glass cutting boards were twice as liekly to contract salmonella poisoning as those who use wood. Science has also shown that sponges are bacterial incubators, and thrive with the moisutre and food crumbs it picks up after use and should not be used in the kitchen. Other studies have shown that throwing a sponge in microwave may not kill bacterial like salmonella (and may ignite a microwave). How do you know it get's hot enough to kill the bacteria? Solution: use dish rags that can hang and completely dry out after use.

    To read more about the above studies see: Dean O. Cliver and Nese O. Ak's work at the University of Wisconsin.

    And see Philip H. Kass' work at the University of California Davis.
    Laura Klein - OrganicAuthority.com

  2. Laura, thanks for your worthwhile addition to my article. I am, indeed, familiar with Dr. Cliver's work on cutting boards. In fact, I mentioned that issue in my book, "Food Safety: Old Habits, New Perspectives". Nevertheless, even wood boards need to be decontaminated. Plastic and glass boards can be washed on a hot cycle in the dishwasher or disinfected with bleach.

    As for microwaving sponges, if the sponge is thoroughly wet (doesn't have to be dripping), it will heat up enough to kill Salmonella without burning. If the sponge is microwaved long enough to generate serious steam in the microwave (minimum 30 seconds, but shouldn't take longer than 1 1/2 minutes, even with an old microwave), the Salmonella will be killed. It should get hot enough that you need rubber gloves to pick it up comfortably. Likewise dishrags. Salmonella and other pathogens can survive air-drying.

    Thanks for visiting.

  3. Questions:
    Do salmonella and other pathogens live in poultry muscle meat, or just on the skin and cavity?

    Is the poultry internal temperature of 165 for safety or just for palatability? Why is it so much higher than for beef, pork, or lamb?

    Does the retained water in water chilling 'force' salmonella into the muscle meat? If so, wouldn't air chilled be safer?

  4. @Willobie:
    1. Salmonella and other pathogens typically are on the skin and cavity surfaces. The interior of muscle meat (whether poultry, beef, pork, etc. usually is sterile, unless penetrated. Of course, those penetrations can be very tiny.
    2. The internal temperature is for safety. The higher temperature reflects a higher likelihood that poultry is contaminated (compared to other meats).
    3. I don't know whether or not the water chilling would force Salmonella into the muscle meat, unless the meat is "penetrated" by some injury during handling. But the water chilling definitely spreads Salmonella surface contamination among carcasses that share the same chilling baths. For this reason, I believe air chilling to be safer.


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