GB1357254A - Semi continuous cheese-making process and machine - Google Patents

Abstract

1357254 Cheese curd COMMONWEALTH SCIENTIFIC & INDUSTRIAL RESEARCH ORGANIZATION 22 Aug 1972 [30 Aug 1971] 39021/72 Heading A2B A semi-continuous process for the production of cheese curd comprises the steps of (1) coagulating milk to form a curd and whey, and cutting the curd; (2) cooking the curd in the whey; and (3) holding the cooking curd in the whey to achieve additional firming of the curd; each of the above steps being carried out in a separate vessel, said vessels being arranged in cascade with transfer of the curd/ whey mixture to the next vessel in sequence after each step; in the first vessel, raw milk is mixed with rennin, or other milk-coagulating enzyme, and a bacterial starter culture at a suitable temperature for example 86-88 ‹F, curd is allowed to form, its hardness measured, and the curd cut when a desired degree of hardness is achieved, and the cut curd is held and stirred in the whey, after which the mixture is discharged to the second vessel. In the second vessel the temperature is raised at a predetermined rate for example about 40 min to effect syneresis, to a maximum for example 100-102‹F consistent with optimal bacterial activity, and the mixture is held and stirred until the bacterial activity has produced the desired acidity, for example for about 25 minutes, after which the mixture is discharged to the third vessel. In the third vessel the mixture is held and stirred until the curd is properly firmed for example for about 55 minutes, whereupon it is discharged to the next stage of the cheese-making process. The process is so operated that the residence time of the curd whey mixture is approximately the same in each stage, and the total time for all operations following the cutting of the curd in stage (1) is 100-140 minutes: A suitable apparatus comprises three vessels corresponding to the above three steps, the first being provided with agitation means, for example a fixed speed stirrer, means for maintaining the temperature, for example thermal insulation, and cutting means, and discharge means, preferably tangential to the second vessel; the second vessel 'being provided with variable speed agitation means, heating and temperature control means, and discharge means to the third vessel; the third vessel being provided with agitation means, preferably a fixed speed stirrer, temperature maintaining means, preferably insulation, if desired means for removing a portion of whey from the mixture when the apparatus is in use, and discharge means. Transfer between stages is preferably effected by gravity and so arranged as to minimise and damage. The operation may be controlled by sequence timing means. pH may be measured and recorded, and the first vessel may be provided with a device to sense curd firmness, for example a displaceable surface which contacts the body of the curd, and a receptor comprising a pressure sensitive element which can be disposed in the body of the curd to detect pressure fluctuations caused by the displacement of the displaceable surface. Suitably the device may comprise two fluid filled cells closed by diaphragms, the diaphragm of one cell being displaced by forcing fluid in and out of the cell, the resultant pressure variations in the second cell being detected electrically.