Letters

Garbage-can superiority

Perhaps the protagonists of "Ka-boom!" (SN: 6/6/98, p. 366) should be looking for something more fundamental than fortuitous geometry to explain the superiority of a $6 garbage can to a $1.2 million Hydrodyning tank as a vessel for explosive meat tenderization. It might be worth questioning whether water immersion and chemical explosives are truly key to the process or merely carried over from Long's original inspiration.

In the tank, a contained system, only the explosive explodes; everything else experiences compressive or implosive shock waves. But when garbage can containment fails catastrophically, there's a sudden decompression: The can and water explode, and the meat, trying to do likewise, is pulled apart.

I wonder what would happen to a tough cut of meat in a vessel engineered to discorporate totally and instantaneously—but restorably. How much cleaner, cheaper, and simpler it would be to just put such a tank in a containment cage and add only meat.

David Bortin
Whittier, Calif.

Sorting through soy

Regarding the article "Soyanara, heart disease" (SN: 5/30/98, p. 348), there is considerable disagreement as to the nature of the active component of soy proteins. We are convinced that isoflavones have little if anything to do with the cholesterol reduction. We have, in fact, evidence that genistein may even raise cholesterol. We have recently uncovered some components of soy protein (that are not isoflavones) that are likely responsible for lowering cholesterol.

Cesare R. Sitori
Università Degli Studi di Milano
Via Balzaretti, Milano

In the article on soy, there is a seeming inconsistency. The caption says "Ground soy protein is one of the most concentrated sources of isoflavones." However, elsewhere the article states that in a trial, each volunteer was asked to drink a "milkshake" with 25 grams of soy protein and that some of the shakes contained negligible amounts of isoflavones. How can that be if soy protein is a concentrated source of isoflavones?

Richard E. Winkelman
Los Altos Hills, Calif.

The only reason that some protein shakes had "negligible" amounts of isoflavones is that these hormonal agents were filtered out by the manufacturer specifically for the experiment—precisely so that effects with and without them could be distinguished from the effects of the protein that they normally accompany. —J. Raloff

Veggie wash

The article "Wash-Resistant Bacteria Taint Foods" (SN: 5/30/98, p. 340) referenced the use of a mixture of vinegar and hydrogen peroxide in a dip to wash vegetables. Since I'm not a grocer or restaurant owner, I probably won't need the commercial product, so would it be possible to find out the ratio of vinegar and hydrogen peroxide used by Sumner and whether the vegetables should be rinsed?

Charles Burdine
Austin, Texas

The new commercial dip evolved from Sumner's earlier data showing that spraying foods with off-the-grocery-shelf white vinegar and off-the-drugstore-shelf hydrogen peroxide killed many pathogenic bacteria—not only on foods but also on kitchen counters. An archived Food for Thought on the research is at our website (go to  http://www.sciencenews.org/sn_arch/9_28_96/food.htm ). Sumner put each sanitizer in a separate plastic spray bottle and then moistened the object to be disinfected with each spray. It doesn't matter which comes first. Because the treatment is nontoxic, it need not be washed off. —J. Raloff

 I was interested to read the article about wash-resistant bacteria. I grew up in Saudi Arabia. Since we had no idea who might have touched the produce brought in for us or what was used for fertilizer, practically the first thing we learned upon our arrival was to wash all fruits and vegetables in a solution of chlorine bleach and water.

It appears that perhaps I should return to this regimen even for food raised in the United States!

Christine Crawford-Oppenheimer
Poughkeepsie, N.Y.

Interestingly, at the same American Society for Microbiology meeting where the work on vinegar and hydrogen peroxide was reported, Michael J. Casteel of the University of North Carolina described using chlorine to successfully disinfect strawberries tainted with pathogenic viruses.

However, Sumner's work indicates that chlorine bleach is far less effective than the combination of vinegar and hydrogen peroxide at killing bacteria.  —J. Raloff

 

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