The effect of glucose and heat sterilization on bacterial assimilation of cystine.

The various permutations of the Maillard aminosugar "browning" reaction (Maillard, 1912) have attracted the attention of microbiologists only within recent years, although food technologists have long been concerned with this class of reactions (Kline, 1950). Although Lewis (1930) warned of the effects of such reactions in bacteriologic culture media, their potential significance in many types of microbiologic investigations may not be appreciated generally. More recently, however, accumulating evidence for an influence of Maillard-type reactions upon microbiologic assays (Hill and Patton, 1947; Patton and Hill, 1948; Camien and Dunn, 1950) has attracted some interest in conditions of sterilization which affect the availability of amino acids for bacterial assimilation (Rabinowitz and Snell, 1947; Riesen et al., 1947; Lankford and Lacy, 1949; Dawson and Robson, 1950). This report amplifies and extends an earlier note (Lankford et al., 1947) on factors which influence the bacterial assimilation of cystine in heat-sterilized culture media containing glucose.