The food enzyme mucorpepsin (EC 3.4.23.23) is produced with the non-genetically modified Rhizomucor miehei strain FRO by DSM Food Specialties B.V. The enzyme can be chemically modified to produce a thermolabile form. The food enzyme is free from viable cells of the production organism. It is intended to be used in three food manufacturing processes: processing of dairy products for the production of (1) cheese, (2) edible rennet casein, (3) fermented dairy products. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to about 0.072 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 2000 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, results in a margin of exposure of at least 27,778. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and five matches were found. The Panel considered that a risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, but is considered low, except for individuals sensitised to mustard proteins, for whom the risk will not exceed that of mustard consumption. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.