Olive oil made by a goy

My friends father would like to ask the following :
He has Arab workers some of them are Muslim and some Christians , One of his workers gave him a bottle of homemade olive oil ,Would that be kosher to eat or we cannot trust it is really just olive oil?
Thank you

Yes. It’s kosher.
The Ram”a has a beautiful Teshuva on this.

Thank you for your response ,
I forgot to mention in my question that this event occurred in Israel , does that change the answer?
Would it be possible to get the location of the Rama’s tshuva?
Thank you

No difference.

Rama is 53 & 54

http://www.daat.ac.il/daat/vl/shut-rama/shut-rama07.pdf

Does this mean we can have plain olive oil at any salad bar location? What about red wine vinegar. Is that an issue because of grapes?

Olive oil, no problem.

Red wine vinegar can be a problem

Ok thanks, would fresh lemon juice be a problem? Sometimes they pre squeeze it and not sure what knives they used.

On a side note, does balsamic vinegar need a hechsher? Is it like red wine vinegar problematic?

Lemon juice is fine

Balsamic vinegar is same issue as the red wine vinegar