Want to take 2 small bottles (100ml) each of olive oil & balsamic vinegar from Australia to California for family is that ok? If so do you declare it in hand luggage or can go it go in my big case

You can put those in either bag, but as long as in containers of 100 millilitres (volume), 100 grams (weight) or less. Containers larger than 100ml will be confiscated. And if you put those in your carry-on baggage, you should present it separately for screening.

@a1mee - the issue is not the amount, the issue is whether the items are allowed into the US. And it is simply not true that containers in checked bags have to be 100ml etc or less. New posters are welcome here, but please get your facts straight.

@gentle - a quick search turned up this: https://www.cbp.gov/travel/us-citize...stricted-items Not sure whether California has additional restrictions, or how they would be enforced at an airport.

From thursday's link: " As a general rule, condiments, vinegars, oils, packaged spices, honey, coffee and tea are admissible. "

The general rule clause is worth noting, but most likely you'll be fine. And yes, larger amounts would be allowed in checked bags.

I have imported larger bottles of both oil & vinegar into the US several times - no issues. They are allowed into the US without an issue.

US customs & border control does not care how you transport them - hand luggage or checked.
Airport security does care. Nothing larger than 100ml can be in carry on bags. They will not be confiscated if they are in your checked bags.

No probllem in checked baggage, as previous posters have noted. Only issue would be breakage, so use bubble wrap or other protective packing material.