Homemade FODMAP-friendly garlic infused oil kept beyond 4 days runs the risk of growing botulism, a toxin that can be fatal. Make the oil as directed, ensuring you properly sterilise your jar and place it promptly in the fridge. Use the oil within 3-4 days or freeze (see more below). If you're uncomfortable with the process, you can buy stabilised garlic oil instead. It doesn't taste nearly as good, but it still adds a garlic hit.