Tuesday, October 13th, 2009

Food Safety, Irradiation and Packaging

vegetables Yesterday, Representative  Mark Schauer (D-MI) announced $1 million in federal funding for the International Food Protection Training Institute in Battle Creek. According to the Congressman, if President Obama signs the bill into law,  the funding “will help strengthen the important work that is already underway at the Institute to make sure food inspectors have the necessary skills to keep our food supply safe.”

When it comes to food safety, skilled inspectors are important — but so are safeguarding tools such as irradiation and special protective packaging.

In the wake of deadly national outbreaks of salmonella, E. coli and listeria monocytogenes in a variety of foods, safety is high on the priority lists of federal and state legislative and regulatory bodies across the U.S.  There has been a renewed push for irradiation of food to eliminate pathogens and extend shelf life.  Food irradiation involves exposing food to a measured dose of ionizing radiation from gamma rays, electron beams or X-rays to destroy microorganisms and the illnesses they may induce.  FDA first deemed food irradiation safe in 1963, and since then the Agency has approved its use for sterilization of meat, poultry, spices, wheat and wheat powder, and fresh produce.   Irradiated foods can be recognized on grocery store shelves by the presence of the radura symbol.

An interesting challenge arises from the fact that foods are often packaged prior to irradiation to avoid recontamination.  Before a packaging material can be chosen to hold a food during irradiation, the effects of radiation on the stability of the material must be considered carefully.

In the case of plastic food packaging, for example, irradiation may cause either cross-linking (the joining of two polymer chains) or chain scission (the breaking of polymer chains).  If cross-linking occurs during irradiation, the migration of packaging materials into food is not likely to be increased. But if chain scission dominates during the reaction, then lower weight, mobile molecules form that may migrate into food.

Toxicity data is relatively sparse on radiolysis products that may migrate into food from irradiated packaging materials.  There have also been comparatively fewer studies done on the effects of irradiation on plastic  food packaging materials than there have been on irradiation of medical devices and pharmaceutical products.  Migration and toxicity data of this nature are often generated by industry in the process of seeking FDA clearance for new food packaging applications.  To date, however, there has been little economic incentive for companies to spend the $60,000 – $80,000 required for testing to prepare a food additive petition or food contact notification for a material to be cleared for use, often in very small quantities, in a specific application like irradiation with a correspondingly limited market.

Expanding the practice of food irradiation is a means of enhancing food safety. The challenge, however, is that there are relatively few food packaging materials approved by FDA for use in contact with food during the irradiation process.  Companies will likely need market incentives, tax credits or other special funding if they are to finance testing of food packaging materials for irradiation.

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