Read this before making homemade infused olive oil

Flavored or infused oils can be a great way to add flavor to marinades and dressings. But if you plan to make flavored oil at home, there are some things you need to keep in mind.

Like many homemade preserved foods, there is a risk of botulism (Clostridium botulinum). C. bot can live in oxygen-free environments. The fresh herbs, fruit or vegetables that you use to flavor or infuse the oil can be contaminated with C. bot spores. Fresh produce also contains water, which allows the bacteria to live and grow. To prevent bacteria from growing, be sure to keep infused oils in the fridge and use them within a short amount of time. (See tip below)

If you want to try your hand at making flavored oil, here are some tips to keep you safe.

• Consider using dried ingredients. Dried herbs and spices do not contain water and are safer. [2]
• Sanitize your containers by boiling them. Items must be boiled for 10 minutes in order to kill C. bot. [3]
• Consider acidifying garlic and herbs before using them in infusions.  [4]
• Refrigerate your infused oils and keep them only for a few days. (Note, most olive oils will solidify slightly in the refrigerator. Bring the infused oil to room temperature before drizzling onto cold foods. ) [5]

Here are some infused oil recipes to try:

• Herbed Olive Oil
  This recipe uses chopped fresh herbs and lemon zest.
• Garlic Flavored Olive Oil
  This oil is heated on the stovetop. It is a good base for some other recipes. 
• Garlic-and-Lemon-Infused-Oil
  This oil combines garlic and lemon zest with olive oil. It is great for drizzling over seafood and dipping bread.
• Hot Pepper Oil
  This recipe is an alternative to using just red pepper flakes to spice up your Italian dish.
• Rosemary-Infused-Olive-Oil
  This is a simple recipe that you can make with rosemary or herb of your choice. It's also great to make as gifts!

References

[1] Clostridium botulinum & Botulism (USDA) 

[2] Safe Homemade Flavored and Infused Oils (University of Maine) 

[3] How to Infuse Oils, Vinegars, Liquor or Honey (NC State University) 

[4] Herb Infused Oils (Clemson University) 

[5] How to safely infuse oil for homemade gifts (University of Georgia)