1. ALL the milk at the grocery store is antibiotic free. It is all tested. Every drop. When antibiotics are administered to cows, a certain established withdraw period is established for each antibiotic, and those guidelines must be followed, or the testing will detect the antibiotic, and your milk will be run down a drain along with whatever other milk the tainted milk came into contact with. The farmer is responsible for this lost milk. One 5000 gallon bulk milk truck costs about $6500 to the farmer
Animal antibiotics are highly regulated, and labeled by the FDA. The FDA has removed certain products from animal use over the years to protect certain classes of drugs for human populations. Most on farm antibiotics approved for food animals are forms of penicillin, or tetracycline.
Some farms use antibiotics to promote feed efficiency. These classes of drugs are what those in the organic movement use to give the idea that cows are pumped full of drugs. The funny thing is these drugs like Rumensin, will not pass through the digestive system to the body. They stay with the digestive tract and are passed through the cow. They are fed in very low amounts and do not pass into milk.
2. Pasteurization kills bacteria
3. You didn't ask the question but I will answer the next question, about hormones. All cow's milk contains rBST (including organic), the bovine growth hormone. It occurs naturally. Some animals are given supplemental rBST. Their milk is indistinguishable from milk produced without supplemental rBST. There is a large movement in the United States to get rBST removed from the market by dairy farmers. We see it as a way to lower production, especially on large "factory" farms, in order to raise the overall price of milk. Pure supply demand dynamic
4. The integrity of the organic products at mega stores like WalMart. These products are "organic" in name and by the liberal interpretations of the rules. They are trying to produce as much "organic" products as possible to meet demand. I will add that steps are being taken to close some loopholes. Like in dairy cows for example, to qualify for organic labeling cows must have access to pasture. The definition of pasture, for how long the cows must be on pasture, and how many cows may be on that particular piece of land were never established. By definition Pasture can be a 1/4 acre piece of fenced in dirt attached to the end of a 700 cow barn. That is a flat out joke. The organic industry knows their credibility is on the line when things like this are pointed out. They are working to standardize and regulate these things.
Some people/firms sneak around organic rules and use standard products, because those products are safe, and undetectable. However if they goof up it will get caught by the same testing non organic products must go by. I know of one truck load of "organic" milk that was rejected because of antibiotics detected in the milk. Gee, how did they get in there? The farmer used a antibiotic on one cow, did not tell anyone, and the hired help did not know to withhold her milk. Viola!
To sum it up if you feel that you want to use organic products, buy from small Farmers markets, for local products that are produced under Certification that it is indeed organic. Or buy from well known stores like Whole Foods, or Wild Oats. Just don't buy into the idea that these products were produced using love and magic fairy dust.