Visiting my dad at work while growing up meant weaving through grocery store aisles, saying hello to the lobsters in their tank by the deli, and — if I was lucky — dancing around in a giant walk-in freezer. It also meant witnessing expert-level grocery shopping in action.

After 35 years as a store director for the Northeastern grocery chain Market Basket, it’s safe to say my dad knows his way around a supermarket, including the secrets to better shopping.

Written with a pen on an index card, his shopping list is always organized by each product’s location in the store. Since he knows where everything is — as well as what’s on sale and the price down to the cent — it makes each grocery trip incredibly efficient.

Even when faced with an overwhelming number of products on a shelf, he doesn’t hesitate when deciding which ones to buy. He’s also shared tons of grocery wisdom with me over the years, including: Never drink directly from a single-sell soda can without washing it first; always, always check that the eggs in a carton aren’t cracked before purchasing them; and if you think for even a second that the deli turkey smells weird, throw it away.

Now it’s my honor to impart his wisdom to you. Next time you’re shopping, keep in mind these tips from someone who knows the ins and outs of the grocery game from decades of experience.

If meat is vacuum-sealed, pay attention to how the package feels

While I was visiting my parents recently, my dad opened the fridge one day and took out an unopened package of bacon that my mom had bought while grocery shopping. (Notably, he hadn’t attended this shopping trip, so he hadn’t been able to give his input.)

I saw him lift up the bacon as if weighing it with his hand, before shrugging with an expression of disappointment and throwing the package away. This might seem wasteful, but it’s a strategy for avoiding food that could make you ill, which is well worth discarding an item.

My dad explained that when you’re shopping for vacuum-sealed meats like hot dogs, prepackaged deli meats, and bacon, you should always pick up the item to make sure it’s firm and airtight. If it feels flimsy or the plastic wrapping appears loose, it likely means there’s a pinhole leak in the product, which can cause the food to expire much more quickly.

“The product shouldn’t be able to move. If you pick up hot dogs and you can move the individual hot dogs inside the package, it’s no good,” he emphasizes.

Don’t be afraid to buy private-label store brands

If you’re looking to save money — and who isn’t — don’t be afraid to shop a store’s private label version of your favorite product. It’s likely just as high quality and may even be from the same producer.

This wasn’t always the case. Many private label grocery brands used to save money by using lower-quality suppliers, but my dad notes that today, “most companies won’t put their name on something that’s not top quality.” He also notes that store-branded items are “usually made by the same people that make the premium brand names.”

One easy way to verify this for meat, dairy, and eggs is by checking the EST number, or establishment number. This is a code assigned to the plant where the product was made. You might find identical numbers on the packaging from different brands, which shows that two separate items were produced at the same location and their key difference is just marketing.

Per my dad, “If you went to pick up store-brand hot dogs, the USDA requires an (establishment) number to be posted on the label, and it’ll say this product was produced in plant number 5831. Well, if you go over and look at the national brand, and it’s got the same plant number, that means the same company made it.”

Be discerning about the per-unit price

Many shoppers go to bulk retailers like Costco or Sam’s Club hoping they’ll offer lower prices per unit when buying groceries in larger quantities, and while this is often true, it isn’t always the case.

You may think you’re automatically scoring a deal by buying in bulk, but my dad recommends always comparing the unit price to be certain you’re getting the best value. “In a bulk store, you’re paying a yearly fee just to be able to shop there. If you can get something on sale in a traditional supermarket, like Market Basket, we’re a low-price operator, so a lot of our items are actually cheaper than the big store items. And you don’t have to buy as much,” he explains.

This tip may be especially helpful for people who are grocery shopping for only one or two people, or the many consumers who don’t have access to a bulk store to begin with. In the words of my dad, “A good shopper should always look at the unit price.”