Can a Jew borrow a cup of sugar from his non-Jewish neighbor?

Question

I'm not specifically asking about stealing and owing concerns, although those may also be of interest.

My question is actually: Can we use kosher-labeled ingredients from a non-Jew's home?

(I include here ingredients, like sugar, that generally don't require a hechsher.)

So:

Can we borrow a pinch of kosher-labeled sugar, rice, flour, coffee, or spices from a non-Jewish neighbor who has already opened and used them?

Can we accept a gift of fruit or hechshered chocolate from a non-Jewish boss?

And even:

Can we accept a gift of unopened Extra Virgin Olive Oil from a non-shomer-Shabbos Jewish friend? (What about opened??)

EDIT: Would like to see a text-based source for the concern with opened products.

Answer 1

As @DoubleAA hinted, once a packaged product is open, and esp. if opened in a non-Jew's kitchen, many questions regarding kashrut arise.

A bag of sugar can pose a big problem. What utensils went into that bag? Was it a non-kosher utensil? In baking, perhaps, the person had his hands in a non-kosher baked mix and stuck his hand in the sugar bag? Essentially, the packaged kosher sugar is now non-kosher, perhaps. Same problem with the other items in the list. The item has to be non-opened and have a reliable kosher symbol.

Fruit is automatically OK if it is whole and non-Israeli produce. You should rinse it, and you may have to inspect it for bugs and other insects, though. I'll try to edit in a link about this, later.

According to OU (or Star K) (Have to edit in link when I find it), a closed bottle of extra virgin olive oil is kosher without any labeling. If it's open, I would question it being kosher, despite the fact that it has a tiny spout and it's not too likely that unkosher food may have fallen in to the oil. However, touching the spout when your hands have been in contact with non-kosher food and considering that the spout is usually plastic which is absorbable, MAY still make it non-kosher. That's something worth investigating a bit further.

Opened boxes of chocolate pose the same problem as the opened box of sugar. Even is every piece is whole and all the pieces are there and the chocolate is kosher supervised, you don't know who or what came in contact with it.

Answer 2

Yora daiya 118.1

יין ובשר וחתיכת דג שאין בו סימן שהפקיד או שלח ביד עובד כוכבים צריך שני חותמות אבל יין מבושל ושכר או יין שעירבו בו דברים אחרים כגון דבש וכן החומץ וחלב ומורייס ופת וגבינה וכל שאיסורו מדברי סופרים שהפקידו ביד עובד כוכבים מותר בחותם אחד

Says that things that a not kosher substitute of will be forbidden from the torah (ie wine ,meat, or fish) need 2 seals when sent with a goy (we are afraid that he might have substituted it

But if the substitute will be Rabbinicly forbidden (ie cooked wine, beer, wine with other additives, milk, fish oil, bread, cheese then it only requires one seal

From this I understand that if the substitute can only be kosher it can be used (by law, but it is good to be strict becouse of the possibilities in the answer above) without a seal

So all of your examples would be kosher