Packaged lettuce


I have a consumer question... I buy a lot of cut lettuce. This lettuce comes two ways. One is lettuce only and the other is lettuce mixed with cabbage and carrots. This produce is then packaged in a plastic bag and usually vacuum-packed.  Most of the time it has a bad smell and taste compared to the purchase of a head of lettuce which I cut up myself.  Is there any way to prevent the development of the bad taste? Or more importantly, is there some way to remove the taste?  I've tried to wash it in vinegar, water and re-dry, and nothing seems to work. (C.R.L.)


We have done some storage tests on packaged lettuce products. The modified atmospheres that develop in the bags to maintain visual appearance may cause the development of off-odors. There may be several volatile compounds involved but we have demonstrated that ethanol and acetaldehyde increase greatly after about 10 days from packaging. These compounds are associated with very low oxygen concentrations (which help retard discoloration of the cut lettuce). To minimize off-odors in the salads you buy, always check the "best if used by" date on the package to buy the freshest product possible. Also buy product that is cold and keep it cold. These off-odor problems are aggravated if the bagged products are exposed to temperatures above 5C (41F). Since the volatiles are produced by changes in the product's metabolism, washing will not remove them. I hope this is helpful. --Marita I. Cantwell