Research performed by the National Center for Home Food Preservation confirmed that mixtures of garlic in oil stored at room temperature are at risk for the development of botulism.
Garlic-in-oil should be made fresh and stored in the refrigerator at 40°F or lower for no more than 4 days. It may be frozen for long term storage for up to several months. Package in glass freezer jars or plastic freezer boxes, leaving ½-inch headspace. Label, date and freeze.
Reference: Nummer, B.A., Schaffner, D.W., Fraser, A.M. and Andress, E.L. (2011). Current food safety issues of home-prepared vegetables and herbs stored in oil. Food Protection Trends 31(6): 336-342.
Page reviewed February 16, 2015.