How much should I eat before taking antibiotics?

That’s fine. All you need is enough food to get your digestive juices going and to stimulate the stomach to produce acid.

That ensures the medication is quickly assimilated and does not cause gastric irritation.

But better than a sausage would be something which takes a little longer to digest, like wholemeal/granary bread or maybe an apple. A good quality sausage is digested so quickly that it may not allow time to digest the antibiotic. Ironically, a low-quality sausage which contains more rusk (basically, bread) than meat is better in this instance.

Eat a half slice of bread or toast or a full slice. As long as something is in your stomach to keep you from feeling like you have the alien eating your insides. Even a couple of crackers will do. Or a couple of cookies.

I would eat something like bread with it, Something spongy. Especially if it's amoxicillin.