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Vegetable Security

To the Editors:

The article "Safer Salads" by Jorge M. Fonseca and Sadhana Ravishankar (November-December) reminded me of my early work as a graduate student on the contamination and decontamination of vegetables. I did this work with a fellow student, Lloyd Falk, and our professor, Willem Rudolfs, at the Department of Sanitation, Rutgers University in 1948-49 with publications in 1950-51. The work was supported by the U.S. Army, which was concerned with the safety of vegetables grown in Japan on sewage farms.

We conducted both laboratory and field experiments, mostly on tomatoes and lettuce, using E. coli, Salmonella, Shigella, Ascaris eggs and Entamoeba hystolytica cysts. We found that bacteria were extremely hard to completely remove or kill, even with a variety of both anionic and cationic agents. Ascaris eggs could be removed but not killed by some washing agents, but seldom at 100-percent levels. Entamoeba hystolytica cysts were readily killed by air drying in a day or two in both the laboratory and the field. Air drying worked in all cases but took much longer with sewage and bacterial mixes.

This work may be of interest first because of the date—nearly 60 years ago—and second because we found pretty much the same results reported in the article. I still shudder when I see plastic packages of moist salad mixes or spinach in supermarkets rather than fresh open-air displays of the same vegetables.

Robert A. Ragotzkie
University of Wisconsin, Madison

To the Editor:

The excellent and timely article on produce safety and sanitation should be required reading for everyone involved in fruit and vegetable production. However, although mention was made of pre- and post-harvest precautions, there was no explicit reference to the importance of proper care during actual harvest.

Mentioning the need for better availability of sanitary field latrines and sanitizers would have been appropriate in pointing out yet another, and essential, step in breaking the chain of disease transmission.

Howard Kaplan
Chevy Chase, MD

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