Botulism poisoning in garlic marinade?

In April of 2008, I bought a plastic bottle of garlic marinade and I still have it in my refrigerator. It's made of garlic, oil, vinegar, black pepper, parsley, oregano, lemon and salt. I may have added some olive oil to it back when I first bought it. What I'm wondering now is if it's still safe to eat. I've heard forever that vinegar is supposed to preserve some foods for a long time. But today I read in a garlic cookbook about something called botulism poisoning in garlic and other food preserved in oil. Acoording to the book, botulism is a toxin in garlic. Is there any chance that any spores may have hatched or bacteria may have grown in the marinade?