Produce protection spawns new products

Aug 30, 2002 (CIDRAP News) – As foodborne diseases increase, innovations for improving food safety are sure to follow. And, in fact, such practices are already showing up in grocery stores and at food science institutions around the country.

On Aug 19, Kroger Co. announced it would offer ready-to-eat produce in all 125 of its Houston-area stores. The announcement follows a 3-month pilot program and extensive market research that showed an enthusiastic customer response. Kroger stores will offer produce treated with the Suntex Safety Wash System. Owned by the Suntex Group, Ltd, of Houston, the Suntex system uses an FDA-approved process. Freshly harvested premium produce is hand sorted and then washed, brushed, and sanitized to eliminate chemical residue. The produce is then sealed in special protective packaging that allows consumers to eat the food without any washing or cleaning at home. The list of currently available foods includes Fuji apples, Gala apples, tomatoes, oranges, peaches, and nectarines. Other fresh produce should be available soon, including cantaloupe, grapefruit, and red potatoes.

In a similar vein, the Agricultural Research Service (ARS) of the US Department of Agriculture announced that apples and citrus fruits are about to get a "uniform new coat" that will keep fruit fresh longer during storage. The goal is to reduce fungal decay, which can destroy more than 25% of the world's harvested fruit.

Rosalie Marion Bliss reports how the technology works in the Aug 21 issue of ARS News & Information. Biological products, such as friendly yeasts, are used for environmentally safe pest control, thus reducing dependence on synthetic chemicals. The friendly biological products work by consuming nutrients on fruit and vegetable skins that otherwise would allow rot-causing fungi to grow.

The ARS report points out that a recently awarded patent explains how chitosan, a natural fungicide, can be combined with Candida saitoana, an antagonistic yeast, by adding a softener. Antagonistic yeast organisms are normally found on fruit and vegetable skins but are harmless to people. Another patent approved this year mixes C saitoana with the antifungal enzyme lysozyme.

ARS coined the term "bio-bandage for banged-up potatoes" to help explain how natural processes can help save valuable food resources. For example, by using natural fungi to reduce the risk of dry rot fungus in the nation's huge potato crops, potato growers hope to stem the $250 million they lose each year because of spoiled spuds.

See also:
ARS article: http://www.ars.usda.gov/is/pr/2002/020821.htm

Bio-bandages and food safety

Comment by Craig W. Hedberg, PhD, University of Minnesota

The two new products described in this report have the potential to contribute to the quality and safety of fresh produce in the marketplace. However, each represents a partial solution to a different problem, and neither can eliminate the potential for foodborne illness from contaminated fresh produce.

The ARS has attacked the problem of fungal decay of fresh produce. Spoilage of fresh produce represents a major cost to the fresh-produce industry and, ultimately, to consumers. Reducing the impact of spoilage will have clear economic benefits to producers, and maybe to consumers. But what are the implications for food safety?

It turns out that the damaged tissues of fresh fruits and vegetables provide good environments for the growth of bacterial pathogens such as Salmonella, Shigella, and Escherichia coli O157:H7. In addition, bruised and decayed areas may provide safe harbors for foodborne pathogens, allowing them entry into the interior tissues of the produce where they will be protected from the action of sanitizing agents such as those used in the Suntex Safety Wash System.

The bottom line here is that while reducing spoilage can contribute to food safety, consumers can attack the problem themselves by avoiding damaged produce or carefully removing damaged areas of produce before use.

The Suntex system directly confronts the food safety issue by washing selected produce items in a sanitizing solution and coating the washed produce to help prevent recontamination. Oxidizing agents such as ozone or hydrogen peroxide are capable of destroying many of the agents we worry about on fresh produce, given suitable concentrations and contact times.

However, there is a growing body of evidence, as noted above, that many pathogens find ways into the interior tissues of the fruits and vegetables, where they are protected from even the most effective of sanitizing agents. Thus, sanitizing washes can never eliminate the threat of fresh-produce contamination.

In practice, washing produce with plain water will reduce surface contamination from enteric pathogens such as Salmonella, Shigella, and E coli O157:H7. Using sanitizers may further reduce this surface contamination but not eliminate it. The Suntex system may produce higher quality produce with a longer shelf life (because they've reduced the populations of spoilage organisms). However, their promise to "offer you our personal guarantee that all Suntex products will be the freshest, safest, and cleanest you have ever tasted" falls short of a guarantee that the products are free of pathogens.

As we look to the future we will almost certainly see other products and processes developed and marketed to improve the safety of fresh produce. As we look to the near past we can see similar products that have come and are already gone. Procter&Gamble developed the Fit Fruit & Vegetable Wash for both home and commercial use. The product had many seemingly desirable characteristics—and many of the same limitations described above. Fit was discontinued because P&G decided the market for the products was too small.

I think the market was too small because consumers rightly judged that the ratio of benefit to cost was too small. The fate of these other products remains to be seen, but I wouldn't look for Suntex to join Band-Aid and Kleenex in our common vocabulary.

Dr. Hedberg is associate professor, Division of Environmental and Occupational Health, School of Public Health, University of Minnesota, Minneapolis.

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