Unigate Dairies

Penfold Road, Worthing -11th April, 1989.

The Dairies’ activities cover an area bounded by the rough triangle of Chichester, Crawley and Eastbourne and it operates for six days per week with Sunday work confined to Planned Mainteance, repairs and renewals of plant. A first phase of plant renewal has just been completed and preparations are in hand for the next and final phase.

The plant is geared to an hourly rating of 4,000 gallons of processed milk with a normal production of 22,000 gallons over a six hour day. The collection of milk by tankers from farmers, delivery to the dairy following by loading onto some eighty electric powered delivery units after processing involves a complicated and comprehensive logistical exercise. To satisfy customers in U.K. all this must be done to ensure delivery as early as possible each day. The re-charging of batteries each day must give rise to a sizeable electrical load which is not evident at first sight.

The quantity and quality of the milk collected is checked in a well equipped laboratory which itself is to be updated in the next renewal phase. Checks for bacteria and antibiotics are routine with water and butter fat contents being assessed to form the basis of payment to farmers. After pasteurisation further tests are carried out to ensure that the final product satisfied mandatory standards prior to delivery to customers.

The milk is stored at a maximum temperature of 5° C and it was emphasised that this maximum should be adopted by customers in their own refrigerators.

The pasteurizing process is somewihat of an anti-climax to the viewer as there is little to be seen other than large stainless steel tanks variously interconnected by stainless steel pipes to a three stage heat plate type heat exchanger performing the pasteurizing function.
In the heat exchanger itself the milk is first heated by indirect hot water to 71.2 deg C (162°F) and held at- this temperature for 15 seconds.
The heat absorbed by the milk is used to preheat the incoming milk and the outgoing milk is finally cooled to 5 deg C by a chilled water circuit.
Thus a thermally efficient continuous circulation is maintained.

The hot water used in the process is heated by steam from a spiral tubed gas fired generator operating at 100 p.s.i. and producing some 2,000 lb. steam per hour. The feed water to the boilers is treated by base-exchange equipment.

The production of some 176,000 pints of milk per day involves washing, cooling, filling, capping, handling and storing some 8 or 9 bottles per second on a continuous basis. Visibly the process is most impressive but the noise created involves the mandatory use of ear protection equipment. The bottle washing water is heated directly by gas and waste heat is transferred from the cooling to the heating phase. Large numbers of new bottles are inserted daily into the system to make up for losses and breakages based on the expectation that bottles can only survive some 35 journeys on average.

Apart from the technical questions which were handled well by Mrs. Ryder, Quality Control Manager and Mr. Clarke, Production Superintendent, the future of milk deliveries in U.K. was discussed in view of the apparent determination of the E.E.C. to discontinue this unique service.