The compliance of a product is tested by means of intra-oral pH telemetry. Applying a standardized method, the plaque pH is measured at least in four volunteers during and for 30 minutes after consumption of the product with an indwelling, interproximally placed, plaque-covered electrode. Products which do not lower plaque pH below 5. 7 under the conditions of this test, lack a cariogenic potential. The erosive potential is measured with a plaque free electrode. The acid exposure of the teeth must not exceed 40 mmol H min. Schachtele Ch. F. et al. (1986). Human plaque acidity models – Working Group Consensus Report. J. Dent. Res. , 65 (Spec. Iss. ): 1530-1531.