“SLIMY WHEY” AT CHEESE FACTORIES TRACED TO FARMS

Bay of Plenty Beacon, Volume 12, Issue 7, 16 December 1947, Page 6

“SLIMY WHEY” AT CHEESE FACTORIES TRACED TO FARMS

Precautions Suggested By Research Officer Dairy cows should be kept away from stagnant water on the farm, approaches to milking sheds should be concreted, and all utensils used in the handling of milk should be sterilised, as precautions against outbreaks of “slimy whey” at cheese factoides says Mr G. J. Hunter, of the staff of the New Zealand Dairy Research Institute at Massey Agriculture College, in an article in the Institute’s latest news circular to dairy factories. Outbreaks of “slimy whey” occur occasionally at cheese factories, particularly during hot weather, writes Mr Hunter. The whey becomes thick and slimy when stored in the whey tanks prior to removal to farms for pig-feeding. Although the whey is still quite safe for use, the sliminess makes it objectionable and difficult to handle, and it is obviously a matter of .importance to locate and eliminate the cause as quickly as possible. It is known that sliminess or ropiness in milk and whey is due to bacterial contamination of the milk after it leaves the udder, but since slime formation frequently does not occur in the whey during the early stages of cheese manufacture, the fact that, milk supplies may be implicated is sometimes overlooked. It is often assumed that the starter used for cheese-making is at fault. However, if the mother and bulk cultures are normal, it is very unlikely that they are the culprits. The organisms responsible may be of various types, and many are relatively heat-resistant. They are found chiefly in soil and water. It is not known why the trouble suddenly flares up. In some instances the causative bacteria are present in stagnant pools on one farm only, and are conveyed to the milk from the skin, udder or teats of the cows. In other cases infected water may gain access to the milk through leaks in the cooler, or again the organisms may be present on poor-ly-sterilised utensils which have been washed with infected water.

The infection may be small, and thus give no sign of its presence before milk is mixed with other supplies at the cheese ‘ factory. A few of the bacteria survive pasteurisation and become established on the factory equipment, and in the whey tank. Storage of the whey gives ample opportunity for the infection to develop in the tank and bring about slime formation. The slimy whey, perhaps only very slightly abnormal at first,, is taken home in milk cans by farmers. In this way the infection increases and spreads to other farms. The trouble thus develops into a cycle and may assume serious proportions. Immediate action must be taken to break the cycle at some convenient point.

Steps taken to overcome the trouble should include thorough cleaning of the whey tank and treatment with chloride of lime or similar disinfectant. The factory equipment should also be sterilised daily. On those farms found to be supplying slimy milk, the equipment should be sterilised by boiling and., or treatment with chloride of lime.

Thorough daily sterilisation of equipment and whey tanks at the factory should check the development and spread of sliminess in milk and whey; similar drastic action at the farms where the trouble originated (provided they can be picked out) will give a final cure.