The following Letter to the Editor was submitted on April 3, 1995, criticizing the work of Daniels et al., who, while working at the FDA, evaluated amounts of free glutamic acid (MSG) in a variety of food. On August 21, 1995, after repeated inquiry by this author, Professor Walker sent a fax communication to say that Food Additives and Contaminants does not publish Letters to the Editor. Given that the information contained in the letter addressed to Food Additives and Contaminants has not been published elsewhere, and Mr. Daniels has chosen not to respond to this author's letter to him, either, a copy of this author's Letter to the Editor is being made available to interested persons on internet. We invite Daniels et al. to respond to our critique. April 3, 1995 Professor R. Walker Editor Food Additives and Contaminants School of Biological Sciences University of Surrey Guildford, Surrey GU2 5XH, UK Food Additives and Contaminants To the Editor: Letter to the editor re: Determination of free glutamic acid in a variety of foods by high-performance liquid chromatography--an article by Daniel H. Daniels, Frank L. Joe, Jr. and Gregory W. Diachenko published in Food Additives and Contaminants 1995, Vol 12, No 1, 21-29. Adrienne Samuels 850 DeWitt Place Chicago, IL 60611 In their paper, "Determination of free glutamic acid in a variety of foods by high-performance liquid chromatography" (1995), Daniels et al. used what appears to have been a single determination of the level of free glutamic acid in a fresh tomato of unspecified type, origin, and condition at the time of testing. They reported that "Fresh tomatoes contained 2270 ppm free glutamic acid..." but did not provide information about variability of measurement, and did not mention that a recovery rate of 197% for their analysis of free glutamic acid in the tomato (noted in Table 2) suggests that the technique used for analysis of the tomato was invalid. Moreover, the authors failed to compare the results of their new methodology with the results of methods they sought to replace, except in the case of tomato paste and fresh tomatoes. Following discussion of methodology, the authors compared the amount of free glutamic acid in a fresh tomato with the amount of free glutamic acid in processed food with labels that declared added MSG. Because a label that declares added MSG provides no information about the amount of MSG in the product, such a comparison would be of no value in assessing the validity of the analytical method used. Because, in addition, the information provided was inaccurate and/or misleading, it would appear that Daniels et al. have used publication of this paper as a vehicle for disseminating false and misleading information about the safety of monosodium glutamate (MSG). Discussion of labeling of monosodium glutamate (MSG) was inaccurate (United States Food and Drug Administration Code of Federal Regulations),(United States Food and Drug Administration, FDA Backgrounder). The authors used the figure generated through a single, potentially invalid analysis (with a recovery rate of 197%), to give the false impression that there is as much free glutamic acid in an unadulterated tomato as there is in products that are labeled as containing monosodium glutamate (MSG). Daniels et al. failed to define the term "monosodium glutamate," and misrepresented the work of Kozukue et al., citing them as having found 2,780 ppm free glutamic acid in tomatoes as opposed to the 27.8 ppm free glutamic acid actually found (Kozukue et al. 1982). Daniels et al. used statistics to create the illusion of an effect that did not exist. They stated, for example, that "...levels...in some foods, such as tomato, were considerably higher than those in some foods that did declare added MSG." However, "some foods, such as tomato" was actually one food, the tomato; and the "some foods that did declare added MSG" that they referred to, were actually the two (out of ten) foods with MSG levels below those found for the tomato by the authors. They made no reference to the fact that there were eight foods with free glutamic levels higher than those found by the authors for the tomato. One of the platforms on which glutamate industry propaganda relies is the assertion that fresh tomatoes are high in free glutamic acid. Glutamate industry representatives maintain that people who say they are sensitive to manufactured free glutamic acid can not be sensitive to free glutamic acid because there are "large" amounts of free glutamic acid in tomatoes; and MSG- sensitive people do not report adverse reactions following ingestion of tomatoes. However, MSG-sensitive people only suffer adverse reactions from glutamic acid that has been freed from protein by a manufacturing process prior to ingestion, regardless of the process used. In their misrepresentation of the level of free glutamic acid found under ordinary circumstances in a fresh tomato, and their selective comparison of free glutamic acid levels in the tomato as compared to various processed foods, Daniels et al. have added to the store of deceptive and misleading information from which glutamate industry interests quote. Adrienne Samuels, Ph.D. 850 DeWitt Place Suite 20B Chicago, IL 60611 U.S.A. REFERENCES Daniels, D. H., Joe, F.L., and Diachenko, G.W., 1995, Determination of free glutamic acid in a variety of foods by high- performance liquid chromatography. Food Additives and Contaminants, 12, 21-29. Kozukue, N., Kozukue, E., Terai, H., and Susumu, M., 1982, HPLC analyses of amino acids in plant materials as DNP-derivatives by use of methyl benzoate as the internal standard. Journal of Food Science, 47, 1584-1586. United States Food and Drug Administration Code of Federal Regulations. 21 CFR 101.22(h)(5); 21 CFR 101.22 (h)(7); 21 CFR 102.22. United States Food and Drug Administration, FDA Backgrounder, HFI- 40, October 1991 BG 91-7.1