Question: I was making brownies from a mix that called for vegetable oil. The only oil I had was olive oil. The brownies came out OK, but I wondered if there are times when you shouldn’t use olive oil.

ANSWER: Olive oil is high in monounsaturated fat and is believed to have other health benefits, including antioxidants. Olive oil is also sometimes used as a substitute for butter in baking, particularly for vegans. Still, there are differences between olive and vegetable oil in cooking:

Taste. There are rustic-style cakes that use olive oil, but the flavor of olive oil is distinctive. It might not work in all sweet dishes.

Price. Depending on the quality, olive oil generally costs more than vegetable oil.

Smoke point. Oils vary in how they handle heat. Olive oil has a low smoke-point, meaning that it breaks down and can be a fire hazard at higher temperatures. Oils like peanut or canola oil can handle higher temperatures better. While that isn’t an issue with baking, you wouldn’t want to deep-fry with olive oil.

QUESTION: How did black pepper become the table spice of choice? Why not salt and cumin? Or “please pass the salt and turmeric”?

ANSWER: While there are many kinds of peppercorns, the familiar black pepper ended up on tables because it is mild and goes with a number of recipes, according to Marjorie Shaffer, author of the new book “Pepper: A History of the World’s Most Influential Spice” (St. Martin’s Press, $26.99).

The reverence for pepper predates the Romans, says Shaffer. Most ancient cultures thought it brought health and cured a variety of ills. It was so sought-after that it drove the spice trade. Even Columbus was looking for it.

“Pepper’s ability to insinuate itself into almost any type of food is probably the reason why it became the ever-present companion of salt,” Shaffer wrote in an email. “Cumin and turmeric cannot be incorporated into nearly as many dishes as pepper.”

QUESTION: How long will cottage cheese keep in the refrigerator? Shall I discard after the expiration date? Can I freeze it?

ANSWER: The date on your container of cottage cheese is probably a sell-by date. It’s so the store will know how long something has been on the shelf (and for you to use when you rummage around to try to get one from the back of the shelf).

It’s hard to give an exact amount of time cottage cheese would last in a home refrigerator because there are so many variables, such as how cold you keep your refrigerator and how often you open and close the door, which affects temperature. If the cottage cheese has no sign of mold and it smells OK, it’s probably fine.

While harder cheeses, like Parmesan and cheddar, can be frozen, softer ones like cottage cheese and cream cheese don’t freeze well. They get gummy or watery after thawing them.