Continuous flow pasteurizer

Pasteurization may be carried out by batch- or continuous-flow processes. In the batch process, each particle of milk must be heated to at least 63°C and held continuously at this temperature for at least 30 min. In the continuous process, milk is heated to at least 72°C for at least 15 s ia what is known as high temperature—short time (HTST) pasteurization, the primary method used for fluid milk. For milk products having a fat content above that of milk or that contain added sweeteners, 66°C is requited for the batch process and 75°C for the HTST process. For either method, foUowiag pasteurization the product should be cooled quickly to <7.2° C. Time—temperature relationships have been estabHshed for other products including ice cream mix, which is heated to 78°C for 15 s, and eggnog, which must be pasteurized at 69°C for 30 min or 80°C for 25 s. 

High Temperature—Short Time Pasteurizers. The principal continuous-flow process is the high temperature—short time (HTST) method. The product is heated to at least 72°C and held at that temperature for not less than 15 s. Other features are similar to the batch hoi ding method. 

Fill the glass bridge with a disposable plastic Pasteur pipette with one continuous flow of agar to prevent air bubbles. The agar will solidify in l-2 min depending on the ambient temperature. 

Although some liquid foods, such as beer and fruit juices, may be pasteurized after filling containers (with warm water or steam applied to raise the temperature appropriately), most are pasteurized in a vat process or a continuous-flow process and then packaged. The vat (or batch) process involves heating in a well-agitated tank for the required time... 

Continuous SSF processes are usually operated in plug flow mode. Such processes will require pasteurization or sterilization of the substrate as it enters the bioreactor, mixing with an inoculum, and at the outlet end of the bioreactor, continuous removal of spent substrate. Such a process was operated on a pilot scale for the production of ethanol from fodder beets by Saccharomyces cerevisiae [81,82]. The bioreactor had a screw within a 4.7 m long and 15.25 cm diameter tube. The screw was rotated intermittently to mix the substrate and move it along the tube. At the front end was a hammer-mill and a pasteurization chamber for substrate preparation and a port for inoculation. New substrate was added, inoculated, and the screw rotated at 12-h intervals, resulting in a residence time of 72 h. 

Add Sephadex G-50 equilibrated with IX SSC + 0.1% (w/v) SDS using a Pasteur pipet. Add the first sephadex quickly, tilting the syringe, then top up carefully to avoid air bubbles, which will cause uneven flow. Continue adding small amounts until the column is equilibrated and no more drops come out from the base. 

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