Wednesday, November 7, 2007

Antimicrobial Film Being Developed for Meats, Veggies, Fruits

I'm not sure how I feel about this news report which follows. A new, edible film has been developed which in the near future may be applied to meats, fruit and vegetables. The product will release anti-microbials when nasty pathogens are present. While in one hand it appears to be a potential solution for the food poisonings we hear so much about in the press, I am also concerned that consuming anti-microbial compounds may not be a good idea. Read the press release which follows, and my editorial comments at the end.

From Newswise wire services:

Ready-to-eat meats are popular with consumers. But after the initial food processing, they are also vulnerable to recontamination by pathogenic bacteria. A solution turns out to be an application of an antimicrobial-incorporated edible film coating that will fend off the pathogens.

“We have used film coatings with raw and cooked ready-to-eat meat products,” said Navam Hettiarachchy, a food science professor in the University of Arkansas System’s Division of Agriculture who led the research for the Food Safety Consortium. “We have also included red meat in our studies as well. In all these products, we have observed a protective effect of antimicrobial incorporated edible films against the pathogens.”

The researchers used a whey protein film coating as a vehicle for the antimicrobials. The actual barrier to pathogens was provided by various combinations of grape seed extract, nisin (a peptide, protein fragment), malic acid and EDTA, which is a ring-forming compound of metal ion known as a chelator.

The tests showed effective results in controlling the growth and recontamination of Listeria monocytogenes, Salmonella Typhimurium and E. coli O157:H7 on ready-to-eat meat products. Hettiarachchy’s team tried different combinations of the antimicrobials and found some variances in levels of effectiveness. For example, in experiments on turkey frankfurters, a combination of nisin, malic acid and EDTA was more effective against E. coli O157:H7 when grape seed extract was not part of the mix than when it was included.

“In most of the cases we focused on the type of meat products,” Hettiarachchy said. “The types of proteins, lipids and other components will vary in each meat product. The protective effect is based on the type of antimicrobials and the product matrix, and the film acts as a vehicle to deliver antimicrobials.” She said the film containing antimicrobials was effective for reducing pathogens on raw chicken, ready-to-eat chicken and red meat, and the degree of effectiveness was dependent on the product.

The key to the workings of edible film on meat is the ability to sustain the release of antimicrobials against the pathogens. The antimicrobials are held in the film matrix by weak forces, not by chemical bonding.

“The antimicrobials can be released immediately or the release can be delayed from the film matrix based upon the affinity of antimicrobials to various amino acids and others that are present in the film,” Hettiarachchy said. “A greater affinity of antimicrobials to the film matrix will facilitate sustained release of antimicrobials and will extend the shelf life of the product.”

Some industrial interest is already being shown in the edible film. Hettiarachchy said there are prospects of its commercialization and some companies are looking into its use for coating fruits, vegetables and even flowers.


DGJ editorial comment: While I would love to see some progress in the war against food contamination, I would resist any effort to have a broad-based antimicrobial compound applied to my food. The contents of that compound don't appear to be a natural part of our environment and it wouldn't fit my lifestyle as a result. However, there is an additional concern here . . . that is, too many products now have an "anti-microbial" element to them, and the result has been huge armies of antibiotic-resistant organisms that we now have to deal with. Microbes learn fast, and they adapt to their environment at light speed. If we allow anti-microbial films on our foods, we would in effect be producing future strains of microbes that would be potentially quite nasty. This idea of a film applied to our food is really a bandaid; instead of developing better quality processes to prevent contamination, companies seek to find a way to simply "spray and go" to avoid the bugs.

Lastly, our bodies have many good types of bacteria at work in various functions. These probiotic bacteria could vanish if the food we ate contained anti-microbial films of the sort described above.


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