Show occasional stirring of milk in can advisable it is much more difficult to reduce the temperature of the creamy layer of milk in the top of a mills milk can than that la in the bottom and yet it Is the top layer that needs the most rapid cooling the cooling of a can of milk set la in a tank of water proceeds as aa follows the warmer milk in the can that la Is being cooled because it Is lighter rises to the top along with the fat globules glo bules of cream for the same reason the warmer water next nest to the can rises to the top As the warmer milk rises it picks up bacteria so BO that the top layer soon contains a higher bacterial count than the lower layers and when a can of milk at 05 degrees F Is put in water at 50 degrees the water close to the can at once starts rising toward the top where it tends to spread over the surface this layer increases until irk in half an hour a layer 2 inches deep will be found to be from 10 to 15 degrees warmer than the water at the bottom this explains why the layer of milk and cream at the top not only contains a larger proportion of bacteria than the lower layers but also why it Is the most difficult to cool it further explains why the occasional stirring of milk in the can as well as water in the tank when the can la Is first placed therein brings about more rapid cooling of the milk wallaces wallacee farmer |