Len Berk, 79, has been working at Zabar’s for 15 years. The self-described foodie answered an ad for a lox slicer, after running his own accounting firm for 40 years.

“I get more compliments slicing lox than I did from saving someone $100,000,” Berk said.

Berk learned most of what he knows now on the job, but he always had a penchant for fish. “I’m a fish person,” he said. “I used to slice my own lox at home.”

On his first day on the job, a Chinese man by the name of David Yan gave him all the advice he needed, saying simply: “Watch.”

“It’s been fun ever since,” said Berk, who works two days a week. “If I worked three, then it would be a job.

“Most of the fun is in meeting people,” he said.

“Buying salmon is very serious to a lot of people,” Berk said. Below, Berk’s guide to navigating your lox counter.

Smoked salmon: Smoked salmon is typically a filet of salmon that’s been cured in a sugar, water and spice mixture. Then, it’s cold smoked over wood chips, such as hickory, which helps it retain a smoky flavor.

Lox: Lox is salmon that’s bathed (or brine cured) in a salt solution for up to 24 hours. Unlike smoked salmon, it isn’t smoked. It’s often whiter than smoked salmon because it sits in a salt water and gets bleached. It’s also much saltier because of that. Berk advised against thinking pinker salmon is better. “The color is not important,” he said.

Belly lox: Belly lox is a fatty part, from the belly of the salmon, and it has a very full, delicate and salty flavor. A lot of people who consider themselves traditional lox connoisseurs for it, Berk said.

Nova: Nova is the mildest of the smoked salmons. At Zabar’s, “Zabar’s Nova” is the most popular smoked salmon by far, he said.

Scotch-cured (or Scottish) salmon: This smoked salmon has a much smokier flavor than nova and is a bit drier. In Scotland, salmon is smoked using oak.

Pastrami cured salmon: This smoked salmon is rubbed with the spices similar to those used to make pastrami, so it’s reminiscent of the deli meat.

Trimmings: Most people don’t even know these are available, because they have to be asked for, and aren’t listed on menus. Trimmings come from the very bottom of the fish, right on top of the skin, and is separated from the more prime cuts. Chewier and made up of darker meat, Zabar’s sells them for $7.95 per pound compared to $34, an option for the cash-strapped New Yorkers who need their smoked salmon fix.

Gravlax: Gravlax is cured but not smoked. It’s cured in sugar, salt and dill and covered in dill. People often serve it with a mustard dill sauce.

Keeping Smoked salmon and lox properly
Keep it in a tight package in the fridge (Zabar’s sells ready-made vacuum-packed salmon). “It can last in the fridge for about a week,” said Berk.“But it is best eaten as soon as possible since the intensity of flavor and firmness of texture will diminish as the days go by.”

Great spots to grab smoked salmon and lox in the city
Russ and Daughters, Murray’s, Zabar’s, Barney Greengrass