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Safety Zone By James Marsden
James Marsden is Kansas State University Regent’s Distinguished Prof. of Food Safety.

Listeria contamination is preventable

(The views and opinions expressed in this blog are strictly those of the author.)

I’ve spent a lot of time over the past year dealing with the aftermath of Listeria recalls. The problem of post-process contamination with Listeria monocytogenes has persisted across all segments of the food industry despite the progress that has been made in Listeria control technologies.  FDA and USDA Recalls for Listeria contamination are commonplace.

In every case I’ve seen, Listeria contamination could have been prevented if integrated control systems had been in place. Here’s a list of things that every plant should consider in addressing the problem of Listeria contamination in Ready-to-Eat foods.

  • Assume that Listeria contamination occurs daily in the plant environment and in your raw materials.
  • Make sure that you have a valid CCP (kill step) for controlling Listeria contamination in raw materials. For many RTE products, this may be your cooking or pasteurization step. For produce, it’s likely a step in the washing process that includes the application of an effective antimicrobial treatment.
  • After the “kill step”, great care should be taken to reduce or eliminate the possibility of post-process contamination in the RTE environment. The environment must be controlled until the product is packaged. Some areas that may require particular attention include drains, air-handling units and of course, all food contact surfaces. Technologies exist that effectively control all vectors of Listeria contamination in the plant environment.  Seek them out and use them.
  • When possible, incorporate secondary inhibitors into product formulations. Listeria contamination can occur at very low levels, but since this pathogen grows at refrigeration temperatures, even levels that undetectable at the point of packaging can become dangerously high during refrigerated storage.  Secondary inhibitors prevent the outgrowth of Listeria, making it far less likely that products will be implicated in cases and outbreaks.  Also, very low levels remain very low or undetectable.
  • In some cases, post-process pasteurization technologies may be applied that virtually eliminate the risk of Listeria in consumer packages. For example, an increasing number of food products are treated using High Pressure Processing to as a post processing pasteurization step.
  • Establish a robust testing program for Listeria in the plant environment and for finished product. If you find Listeria, take immediate steps to eliminate the root cause.
  • Conduct regular process reviews to make sure your process is designed to control Listeria. Most of the catastrophic Listeria problems that occurred over the past few years could have been prevented if processes had been critically reviewed.

I understand that controlling Listeria in food processing environments poses formidable challenges. However, technologies have emerged that make it possible to eliminate Listeria in RTE environments and products.  Follow my list – it could save your company from a recall or public health disaster.

10/13/2014

 
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