Abstract: Methods and media for preparing bulk cultures of exclusively proteinase negative lactic bacteria and methods for making fermented dairy products such as cheese, cottage cheese, and sour cream employing exclusively proteinase negative lactic bacteria are disclosed. In one preferred embodiment, the medium comprises a whey-based, pH-controlled medium containing sufficient nitrogenous nutrients to render the medium suitable for growing proteinase negative lactic bacteria. The medium is heated to inactivate bacteriophage present therein and subsequently cooled to a temperature favorable to the growth of proteinase negative lactic bacteria, and the proteinase negative lactic bacteria are introduced into the medium and allowed to propagate to a population sufficient to serve as an inoculant in making the particular fermented dairy product.

Abstract: Apparatus and methods for measuring milk coagulation time and rigidity in the manufacture of fermented dairy products such as cheese. The apparatus includes a substantially flat, disc-shaped probe which is suspended from a wire into a fermented dairy product-making vessel filled with milk. The probe is reciprocated through a small vertical distance within the coagulating milk in the vessel, and the increasing resistance to the probe communicated through the wire as the milk coagulates is continuously measured. When the measured probe resistance reaches a predetermined value, it is time to cut the curd formed by the coagulating milk. The present invention provides apparatus which can be used on both an industrial scale and a laboratory scale.