Reports have appeared on the harmlessness (6, 7 , 23, 24), purity (15,22,9), determination (12, 13), and fate (14,15,16,9 ) of sorbic acid in foods. The mechanisms by which sorbic acid inhibits mold growth have also been intensively explored (16,8,9). I n addition to the demonstrations that sorbic acid is of value in protecting cheese (22, 23), margarine (20), fish ( 3 ) , pickles (18, 10, 5, 2, 21), gum and sugar solutions (19), citrus products ( l 7 ) , and fruit purees ( I ) against yeast and mold spoilage, the use of sorbic acid on an expanding commercial scale for the protection of other food products (4) including chocolate syrups, refrigerated fresh fruit salads, potato salads, and cold slaw attests to the effectiveness of sorbic acid in protecting foods in general.Two factors have been largely responsible for the growing preferential use of sorbic acid over the other fungistatic agents currently allowed by the U. S. Food and Drug Administration for use as food supplements; these are effectiveness and flavor. Not only has sorbic acid proved to be more effective than benzoic or propionic acid in these applications (3, 19, 20, 21, 22) but the flavor of the resulting foods is not impaired. This difference in flavor quality is due to the need to use on a weight for weight basis less sorbic acid and to the characteristic flavors of benzoic and propionic acid particularly in acid foods. Sorbic acid cannot be used to conceal damage or inferiority in foods; use of this fungistatic agent in plant operations will not permit relaxation in good sanitary practices (16,23). Sorbic acid can be metabolized by molds and quantity thereby reduced, if the ratio of molds to initial sorbic acid concentration is high (16).The present report summarizes studies on the value of sorbic acid relative to that of propionate in protecting cakes against mold spoilage. Mold spoilage is not as serious a problem in cake merchandizing as it is in the case of bread and rolls although the p H of cakes make them more conducive to support mold growth. The higher sugar content, lower moisture, and the use of icings minimize the mold problem in cakes. Mold spoilage becomes serious, however, when cakes are on sale for extended periods, particularly during the summer months, and when the products are of a relatively higher moisture content. Fruit cakes which have long merchandising periods must also be protected. It has become common practice for the commercial baker to add sodium or calcium propionate in amounts varying from 3 to 5 ounces per 100 pounds of batter (0.1875 to 0.3125%) and a t times as much as 7 ounces (0.44%) depending upon the type of cake. I n a few bakeries, notably in Canada, sodium benzoate is used,