@ Leona,
The best way to have garlic juice without preservatives is to make it for yourself in the kitchen.
Tips to make garlic juice.
Requirements:1 bulb of garlic
Mesh strainer
Coffee Filter
Peel one bulb of garlic (this will give you a quarter to a third of a cup of juice depending on the size of the bulb).
Blend the cloves in a small food processor until creamy and strain twice, once through a mesh strainer, then strain that liquid through a coffee filter. That's it. The hardest part is peeling the garlic bulb, which is a bit easier to do if you smash it first.
Once you have some nice juice, combine it with a tablespoon of butter and sauté it to make a flavorful garlic bread topping. Be sure to sauté the liquid long enough to eliminate excess moisture. Keep the heat low. You don't want to burn the butter.
Extracted juice should be frozen in an ice cube tray and then transferred to a plastic bag for storage.