Inhibiting Effects of Amino Acids and Related Compounds upon the Growth of Eaterotoxigenic Micrococci in Cream Pastry

Food poisoning caused by cream-custard pastry products constitutes an important public health problem. Feig (1950) stated that 35.3 per cent of the micrococcus (staphylococcus) outbreaks were caused by bakery products. Of these, 86 per cent were caused by creamcustard pastries. Furthermore, although these products have been incriminated as a vehicle for the transmission of Salmonella infection, 90 per cent of the total number of food poisoning outbreaks incriminating pastries were caused by micrococci. Abrahamson et al. (1952) concluded that the bacteriological quality of several types of cream pastries was unsatisfactory. However, considerable improvement was effected when the proper sanitary procedures were carried out under appropriate guidance. Although the problem remains unsolved, a number of other important contributions have been made. For example, Stritar, Dack and Jungewaelter (1936) suggested a reheating of the filled pastry shell. Also, Ryberg and Cathcart (1942) demonstrated that several types of fruit cream pies did not support the growth of micrococci when milk was eliminated from the formula. Cathcart and Merz (1942) demonstrated that chocolate and cocoa had an inhibitory effect, particularly when milk was not included in the formula. The addition of water instead of milk to the commercial dry mix puddings resulted in a product that did not support the growth of micrococci, but it was considered unpalatable (Cathcart, Godkin and Barnett, 1947). Furthermore, these same authors, in an attempt to prevent the growth of micrococci by lowering the pH of the filling, observed that the amount of citric acid required to inhibit micrococci in a filling containing eggs was so great as to impair the organoleptic qualities. Godkin and Cathcart (1952) have demonstrated that subtilin and especially a combination of subtilin and terramycin inhibited both micrococci and the indigenous, heat-resistant flora of cream pastries. A combination of aureomycin and terramycin also effectively retarded growth of micrococci. The present communication reports investigations on the bacteriostatic properties of certain amino acids and related compounds against enterotoxigenic micrococci experimentally inoculated into cream pastry.