Disclaimer: This is a non-medical opinion. I'm just recalling back many years ago to the Food Handlers training.
Foodborne illnesses (which this would be if it came from the wine) fall into two main categories: Intoxications, and infections. Intoxications come from chemicals put into the food by pathogens - probably no need to define this for winemakers/brewers. Infections happen from the pathogen themselves infecting your body. Cooking kills pathogens, but there is no way to make something safe that contains the intoxicants that the pathogen may have left behind.
It usually takes at least 24 hours to show symptoms from an infection. Many times these infections are mistaken for "24 hour bugs" or other non-specific illnesses, and sometimes are very severe. Most times, what you associate the poisoning with is not what caused it just because of the time it takes between ingestion and the symptoms beginning to show. If the symptoms make you sick in your stomach, your stomach usually sours on something you ate AFTER the real culprit, and people usually associate the illness with what soured in their stomachs rather than the real culprit. Infections do not always have a taste associated with them. E. Coli is an example of an infection.
For intoxicants, they usually, but not always, have very bad tastes associated with them. Obviously, they can be very severe - botulism is an example of a foodborne intoxication. When the possibility exists of intoxications from a foodborne pathogen, never trust cooking or other methods to make the food safe - it may not, and in fact, probably won't.
From your description, I would think this:
1. There is not a guarantee that because you got sick after you tasted the wine that you got sick because of the wine. It might be enough to make me think that it's not necessarily a good idea to taste it again, though ...
2. From the description of a sour taste: It could be something as simple as the juice itself, or an acetobacter or lactobacillus infection. Neither acetobacter nor lactobacillus would be something to cause illness, but they would certainly not be what a winemaker is going for
.
3. It is possible to have something more serious in the wine, but we can't really know if this is the case from the information we have. My thoughts are that there are some of these foodborne illnesses that can be very serious, though, and if you have reasonable suspicions that the wine caused illness, then a new batch of wine is relatively inexpensive compared with medical bills or the long term effects of some type of food poisoning.
