Safe from what
Safe as Milk was created in 1967-09.
The Production Budget for Safe was $33,000,000.
Safe As Mother's Milk happened in 2002.
The Production Budget for Safe House was $85,000,000.
The Production Budget for Safe Haven was $28,000,000.
The Production Budget for Safe Men was $1,000,000.
NoFresh milk is not safe during pregnancy.
Filled milk is not safe for babies as if it is not handled properly it may cause several problems to babies. Mothers milk is always safe for babies.
horse milk sheep milk In Google you can find many references to milk and milk products and their safety, by entering "milk for human consumption". Doing this I found that not only cow and goat milk are safe, but also sheep's milk and mare's milk are safe and available, but not widely.
Yes, the same process that can cause a woman who has never breastfed to start producing milk can be used on a woman who has breastfed, Physical stimulation (Pumping/sucking) or hormonal via drugs/herbs can return milk production.
This is possible, but not common. Most women that breastfeed their baby do not ovulate and hence does not become pregnant. When trying to wean the baby off breast milk, this reduces the hormone production and production of milk slows down. At a stage during this, ovulating starts up again, and you can get pregnant. Some few women do ovulate when breastfeeding. It is not a "fail proof" method of contraception. Only fairly safe :-)