I Point tM labels, made by I Point ABTechnology, are enzymatic time-temperature indicators whose color changes as a result of pH variations due to the ysis of lipid substrates(Summers, 1992b). The label is composed of a capsule which contains a lipolytic enzyme and lipid substrates separated in two compartments. The enzyme and the substrates mix when the barrier between the two compartments broken upon activation, and hydrolysis of the substrates causes acid release. Hence the pH drops and is recorded by a color change in a pH indicator. The color change can be compared with a reference standard printed on another label on the package.