Its Oxy-Clean (bad news) It's only 5gm in 189L (good news). Hard to say at that low level. I would wonder if this is a red wine it may ruin the appearance but again at that low level you might not be able to detect it. I would check the pH and compare to any previous reading you had taken. Check your TA and compare, check your Free SO2 and compare. Finally do a smell test. Does it smell off. Do a taste test does it taste off. That small amount would not cause any stomach upset (in my opinion) The MSDS says "Swallowing can result in nausea, vomiting, diarrhoea, and gastrointestinal irritation." Again probably not at that low level and this is going to react with acids (wine) as it is a base (oxidizer) making it more than likely OK to ingest after it reacts and at that (low) level.