Fuente: WIPO "dairy products" This is an improved preservative composition for milk, the improvement in which comprises the incorporation in the composition of an indicator compound which, when added to the milk, changes colour over the pH range from 6.6 to 4.6, whereby bacterial degradation results in an observable change of colour in the milk. The indicator compound is preferably bromcresol purple, chlorophenol red, nitrazine yellow, or bromothymol blue.