摘要：Rec-assay was carried out on 49 natural food additives (colors: 14; enzymes: 13; flavors: 11; thickenners: 6; others: 4) with the following results being obtained. 1. Nineteen samples showed growth inhibiting activity in the spore plate method. Clove oil (S9 mix -, +), allspice oil, citronella oil, ginger oil and peppermint oil (S9 mix -), all being flavors, were positive. Phyllodulcin was weakly positive. 2. The liquid method was carried out on 39 additives which did not show growth inhibiting activity in the spore plate method. Five of them showed growth inhibiting activity and anise oil, a flavor, were positive (S9 mix -, +). The koaliang and maddar colors, and pullane were weakly positive. In order to compare the spore plate method and the liquid method, five additives which were collected in 1981 and showed growth inhibiting activity in the spore plate method were tested by the liquid method. Rennet, negative in the spore plate method, was weakly positive and Phyllodulcin, weakly positive in the spore plate method, did not show any growth inhibiting activity in the liquid method and the other 3 additives were negative in both methods. 3. Twenty-five additives, about a half, did not show any growth inhibiting activity in the spore plate method or the liquid method, and so judgements on them could not carried out. It is nesessary to develop a more sensitive rec-assay method to detect growth inhibiting activity. 4. Four rec-assay reverse additives were found in the study. It is an important question whether the reverse reaction is related to genetic toxicity or not.
