METHOD AND APPARATUS FOR MANUFACTURING CHEESE OF THE TYPE PASTA FILATA

Abstract: In the production of cheese of the pasta Filata type it is a condition that the cheese substance in warm condition is subjected to a stretching prior to addition of the required amount of salt. It is known to add the salt by placing produced small cheese blocks in a brine, but this requires a relatively long storing period before the cheese can be finally packed and delivered from the creamery. According to the invention the storing period can be shortened considerably when the salt is added by a current injection (at 14) of an oversaturated water/salt-solution immediately after the cheese substance having passed the delivery end of the stretching apparatus (16), such that an even distribution of the salt will be achieved very rapidly by a following vigorous agitation of the substance. Both the storing time and related hard and monotonous labour can hereby be reduced considerably.

Description: A Method and apparatus for manufacturing cheese of the type Pasta Filata. The present invention relates to a method for manufacturing cheese of the type Pasta Filata, e.g. mozzarella cheese. It is characteristic of this manufacturing that the manufactured cheese coagulum in a hot and unsalted condition is transported upwards through a worm conveyor for kneading, here called stretching, of the cheese substance, which is then delivered in a relatively dry condition for further processing. The latter consists in the cheese being shaped into block members which are placed in a brine e.g. for 10-20 hours, whereby the salt penetrates into the outer layers of the blocks; during a subsequent storage period of 5-20 days the salt disperses in the entire cheese. Formerly it has been attempted to shorten the processing time by sprinkling salt on the cheese curd after the stretching process and thereafter kneading the curd anew. However, this provides a less effective salt distribution, as well as a tendency of marbling in the shape of rings of over-salted areas. The temperature of the cheese curd is as high as 60-70°C, and salt combining with the hot cheese will very quickly be absorbed in the cheese curd, and as the curd has a somewhat fibrous structure after the stretching, it is difficult by a subsequent kneading to obtain an extensive evening out of those areas where the salt grains have caused local, high salt concentrations. It is the purpose of the invention to provide a method by which the processing time may be reduced by obtaining an extremely quick salt distribution. According to the invention this is obtained by a continuous supply of an over-saturated salt solution immediately after the stretching of the hot cheese curd, e.g. a 50% roughly water-salt solution, which, by vigorous stirring in or immediately after the supply area, is distributed in the flow of cheese substance. Hereafter this may be shaped, and the block portions need then only be cooled e.g. for 2-3 hours, whereafter they are ready for packing and delivery. Also by the process indicated here there may occur slight variations of the salt contents of different partial areas of the cheese curd, but in that case, these have shown to be unnoticeable. The salt in an aqueous state is easier to distribute rapidly than the salt particles, and at least there will be no partial areas of highly concentrated salt. It has been found fully acceptable to add the slight amount of water with the salt which is necessary as a basis for the over-saturated solution, inasfar as only relatively modest amounts are concerned and as this may be taken into account in the preceding part of the process. On the other hand, the fact that the admixed amount or flow is relatively modest may render it critical to ensure an extremely well-controlled manner of admixture regarding both distribution and dosing, and the invention additionally comprises means for control in this respect. Thus, it is of course important that the admixture dosage is adjusted according to the occurring volume flow of cheese curd. This may be adjusted according to occurring process parameters in the production line, but there may still occur variations which are only partially foreseeable. On this back¬ ground, as one of the said means or measures, it has been found advantageous in connection with the invention to make use of a detector for measuring the actual supply of cheese curd to the area where the salt solution is admixed, as well as for an associated control of the supply of salt solution. Hereby the salt solution may be dosed correctly with a good dynamic accuracy. To be mentioned here as further measures are only to be mentioned a particular positioning of supply nozzles for the salt solution and agitation means developed for this particular purpose. The invention, which additionally comprises an associated apparatus for implementing the said method, is explained in more detail in the following with • reference to the drawing, in which Fig. 1 is a partially schematic side sectional view of an apparatus according to the invention, while Fig. 2 is a perspective view of a portion hereof. As known main portions, the shown apparatus comprises a receiver portion 2 for cheese curd 4 and a conveyor member 6 projecting obliquely upwards therefrom in the shape of a pipe in which are mounted two adjacent spiral conveyors 8 driven from a driving station 10. These conveyors, of which only one is shown in Fig. 1, knead the cheese coagulum which is heated by circulating hot water in the receiver portion 2 and provoke a stretching effect of the formed cheese curd, which is simultaneously conveyed upwards through the pipe 6. When leaving the upper end of the pipe 6 the cheese curd is traditionally conveyed directly via the extension pipe 12 to a shaping equipment, in which the curd is portioned or shaped into blocks of a size appropriate for selling, which are then treated in the manner described above. However, in the system according to the invention this delivery takes place from the conveyor member 6 to an extension pipe member 12 and herefrom to the shaping equipment. According to the present invention, a number of injection nozzles 14 connected to supply lines 16 are placed near the delivery end of the pipe portion 6, through which supply lines an over-saturated water-salt solution may be injected from a supply storage 18 into the flow of cheese curd leaving the pipe 6. This supply takes place through a distributor unit 20 which is provided with valve means for sequential injection of the solution through the respective nozzles 14, such that these are made operative one by one in a predetermined order. The nozzles 14 are placed in different angular positions or generators on the pipe 6 and are furthermore placed with a certain mutual axial displacement relative the axis of the pipe 6. In the connection between the supply storage 18 and the control unit 20 is inserted a pump 19, ensuring that the salt solution may be injected with a suitably high force, and a regulator unit 21 which is operable to control the supply flow of salt solution to the distributor unit 20. In front of the upper end of the pair of spiral conveyors or worms 8 and above the area of the nozzles 14, a special agitator/mixer section with stirring wings 22 is placed directly on the respective worm shafts or - as shown in Fig. 2 - on shaft portions 24 which may be fastened to the end of the worm shafts. These wings are shaped as staves of a rectangular cross section which is turned such that the wings act as conveyor screws, notably for influencing the cheese curd in the opposite direction of the delivery direction from the conveyor worms. When the cheese curd is pressed through the area at the wings 22, a very strong agitation effect will thus occur in the curd, and as this takes place imme¬ diately after the supply areas 14 for the salt solution, an extensively uniform distribution of the solution in the curd will occur hereby. It should also be attempted for this distribution to be uniform in the longitudinal direction, and as mentioned, a sensor is preferably used for detecting the momentaneous flow velocity of the cheese curd to the injection area. As shown, this is obtainable in a simple manner by means of a flow meter 26 placed in connection with the extension pipe 12. The control unit may then provoke a simultaneous regulation of the supply flow of solution through the nozzles 14 by influencing the regulation unit 21. The cheese curd is conveyed from the extension pipe 12 to the said shaping equipment to or through a cooling zone, and merely 2-3 hours thereafter, the block members may be conveyed to a packing station for final packing and delivery. The control of the injections is preferably to be carried out with quite great accuracy, preferably in such a manner that they are effected immediately before the concerned injection area is subject to the reversing effect of a passing agitator wing 22. A computer 23 provides for the necessary synchronizing as well as for a general control of various processing parameters, including a dosage control according to the flow measurement by the sensor 26, which is connected to the computer through a cable 32.

Claims: P A T E N T C L A I M S ; 1. A method for producing cheese of the type Pasta Filata, by which the cheese curd in a hot and unsalted condition is conveyed through a stretching apparatus and thereafter admixed with salt, characterized in that the salt admixture is effected as a current injection of an over-saturated water-salt solution in the conveying area of the cheese curd immediately after its passing the stretching apparatus, and that the cheese curd is thereafter currently subject to a strong kneading, before it is delivered for shaping into block members which may be made ready for delivery as finished goods after a brief storage. 2. A method according to claim 1, characterized in that the kneading after the injection is effected in the conveyed curd material flow by using agitator wings which are obliquely positioned such as to press the material backwards locally in the flow. 3. A method according to claim 1, characterized in that a measuring is effected of the supply volume flow of cheese curd to the injection area, and that the addition of salt solution is adjusted currently according to this measurement. 4. A method according to claim 3, characterized in that the supply volume flow is measured by a flow measurement of that cheese curd which is pressed through an upwardly conveying delivery pipe at the delivery end of the injection and kneading area. 5. An apparatus for implementing the method according to claim 1, comprising a kneading and stretching apparatus for reception, kneading and stretching of hot, unsalted cheese curd, as well as means for subsequent supply of salt to the cheese curd, characterized in that the means for supplying salt consist of means for injecting a concentrated water-salt solution in a flow-trough area for the cheese curd immediately after the stretching apparatus, and that additionally, immediately thereafter means are placed for intensive kneading of the cheese curd before this is delivered for further processing. 6. An apparatus according to claim 5, characterized in that the injection means are constituted by injection nozzles placed in the pipe wall of a conveyor pipe forwarding cheese curd from the stretching apparatus, and that the said kneading means are placed immediately thereafter in this pipe. 7. An apparatus according to claim 5, characterized in that it comprises means for measuring the supply volume flow of cheese curd to the injection area and means for graduating the supply of salt solution in accordance herewith. 8. An apparatus according to claim 5, characterized in that the injection means are provided as a plurality of nozzles which are placed with a mutual distance in both the circumferential and longitudinal direction of the conveyor pipe. 9. An apparatus according to claim 5, characterized in that the kneading means are constituted by rotating kneading wings which are oriented such that they counteract the direction of forwarding the cheese curd of the stretching apparatus. 10. An apparatus according to claim 8, characterized in that the kneading wings are placed at the end σf conveyor worms comprised in the stretching apparatus. 11. An apparatus according to claim 5, characterized by an associated computer controlling the injection periods relative the movement of certain apparatus portions, e.g. the kneading wings, and certain processing parameters.

Inventors: FUGLSANG VILLY, GASBJERG KNUD, JOERGENSEN POUL, FUGLSANG, VILLY, GASBJERG, KNUD, JOERGENSEN, POUL
Applicants: GADAN MASKINFAB, GADAN MASKINFABRIK A/S
Application year: 1992
Main classification: A01J25
IPC codes: A01J25, A23C19