Everyone knows the routine: You go out for a gallon of milk but come back with milk, cheese, potato chips, and many other items. Don't feel bad: It's not you; it's the grocery store. Or, more accurately, it's logistics. Milk is almost always stored at the back of the supermarket, so customers have to walk through most of the rest of the store to get to it. Invariably, there are lots of enticing shelves on the way, so coming out with more than expected should be no surprise. Then again, the setup is not necessarily as devious as it might sound. Milk has to be kept cold when it arrives, and having cold cases near the back of the supermarket, where delivery trucks unload, makes sense. That way, milk -- and other dairy products -- can be refrigerated as quickly as possible. In effect, there's no use crying over unspilled milk: It stays cold, which is good for the consumer, and it buoys sales, which is good for the grocer.
Milking the truth:
- A dairy cow needs to eat approximately 100 pounds (45 kg) of feed to produce 6.3 gallons (29 litres) of milk per day.
- Cows are milked at least twice a day. Before milking machines were invented, farmers milked about six cows an hour; modern milking machines can milk 100 cows an hour.
- Roughly 75 percent of adults around the world have some intolerance to milk because people stop producing the digestive enzyme lactase as they grow older.