Looks ugly doesn't it? It's Trockenbeerenauslese: botrytis affected grapes - pure gold in the hands of a skilled winemakers.
When was the last time you have seen grapes being washed before getting crushed? Sorted - yes. Destemmed- check. But washed? Followed by a blow-dry perhaps? Can't recall that.
We read in a post by Lum Eisenman: "On average, one ton of California wine grapes contains seven pounds of dirt, one mouse nest, 147 bees, 98 wasps, 1,014 earwigs, 1,833 ants, 10,899 leafhoppers and three pounds of bird droppings." Let's not wonder too much about the disturbing accuracy of the count (especially since this is an average, meaning some poor guy had to sort through several tons of grapes). We can agree though that there must be significant amount of ant-poop and the likes coming in with each harvest, not only in California, but also in Rheingau, Bordeaux or any other winemaking region of the world. That sounds less than appetising, and pretty much unhealthy, too.
And fact is, though, that most winemakers don't bother.
The vast majority of winemakers will not wash the grapes in the winemaking process. Good enough the solids get removed with the grape skins or filtered out when the must is transferred from pressing into fermentation vessels.
But what about the microbes and bakteria? Thing is, some of these are very much required in the wine making process, especially when its coming to making use of the natural yeasts sitting on the skins of the grapes. Ask any ambitious winemaker, and he will confirm that local natural yeasts make an essential contribution the aromes and taste of their wine - washing grapes means removing some of the vineyards essence, slowing down the start of fermentation and the need for cultured yeasts to be added, consequently vulgarising the wine.
The very good news is that almost all other microorganisms don't survive the fermentation process, with the high acidity of the grape juice and the alcohol being the major natural purging agents. If anything is left in the process, it will later manifest itself as wine faults - and you are very likely to detect that before drinking.
So, bird poop or not, no human pathogen survive in wine. Assuming the correct application, wine is a healthy product :-). The romans seemed to know when they washed wounds with wine ('If you don't have wine, take medicine'). And even in the middle ages, when winemaking included stomping grapes with bare feet, people knew as well, with wine considered healthier than water.