You can view the facilities, and make a judgement about the cleanliness -- as you might in a restaurant before considering the beef tartare -- and you have likely been buying from this farmer for some time.
Food can be contaminated at any number of places along the supply chain, but I don't see how trust enters into it. It's like trusting that you won't be served a bad oyster, impossible to rule out at even the nicest, most "trustworthy" establishment.
These kinds of risks are similar to the risks of eating beef tartare or oysters (things that I also do fairly regularly, including sometimes in developing countries!), and humans have been reasonably successfully managing these risks for a long time, meanwhile some other humans seem to massively overstate the risks for some reason.
It kind of implies the opposite, that the bacteria don't need to multiply, they're already present.
Have you seen studies that show most outbreaks are from bacteria multiplying in the milk rather than contamination at the source? Since even raw milk is promptly cooled which greatly slows bacterial reproduction, I find it more likely that all the contamination needed to cause sickness happens during processing.