Yesterday I had a long trip with the owner of an ice cream factory and told me this story. They have a very pro-active mashgiach kashrut (the Rabbinate's inspector to ensure the ritual purity of the product) and he examines the stainless steel pots after they are washed. Once he found that a washed and dried container had a white spot inside and decided to declare the day's batch as unclean and non-kosher. In the discussion that followed the mashgiach maintained that the stainless steel walls of the container had exuded old milk, which can be seen as the white spot. The plant engineer explained that stainless steel does no absorb milk and therefore does not exude it, the white spot is calcium carbonate deposits contained in the hard water supplied. All food factories have their kashrut supervisors, well versed in the Gemara but wonderfully ignorant of math, physics and science in general. An enterprising kibbutz is growing strawberries in the air (hydroponics) to ensure the kashrut of the produce, because if one fruit touches the soil, the whole batch may be declared unfit for Jewish consumption. The ice cream factory buys only that kind of fruit. On the other hand, thanks to the strict supervision, the scandal of horsemeat found in sausage in Europe could not happen in Israel. Not that horsemeat is unhealthy or anything.