The grouper at Srey Neang’s fish stall on the western arm of Central Market is impossible to miss. Its fluorescent silver, blue and orange scales are almost blinding in the midday sun. But this doesn’t faze Gisela Salazar Golding, head chef at Chinese House’s Tepui restaurant, who is sticking her fingers underneath the fish’s collar. One way to tell if the fish is fresh, she is saying, is to check that the collar’s interior is red. Another is to look at its eyes: rather than being blurred, white or droopy, they should be perfectly clear.

I am participating in expat2cambodia’s Food Market Tour, led by Venezuelan Salazar Golding. The relocation service company’s idea is that newly arrived expatriates can find out where the best places are to buy fruit, vegetables, meat and fish, from someone who uses the best produce.

After a brief history lesson – Psar Thmey, as it’s known in Khmer, was built in 1937 by French architect Louis Chauchon, and was damaged by Thai bombs in 1939 causing it to close temporarily – Salazar Golding gives us a whirlwind tour around the market, from the sparkling bling sold in its centre to the clothes stalls and the rather dubious iPhones.

It isn’t long, however, before we find ourselves along the market’s western arm, which boasts an abundance of food stalls. According to Salazar Golding, the best time to come to Srey Neang Seafood, halfway along this stretch, is 4.30pm. After a catch off the coast of Sihanoukville in the early morning, the fish are transported up to the capital during the day, she says.

Another crucial box that Srey Neang ticks is that its fish lie in ice. Salazar Golding points out a particular stall a few metres further into the market with shellfish lying in baskets out in the heat where, without water or ice to cover them, they attract flies.

“We’re talking about 35-degree heat,” she says.

Instead, for shellfish, the fare at Tepui is supplied by a stall directly opposite, with a Khmer name, which keeps its crustaceans in buckets of ice. The chef laughs as she picks up a live river lobster with fantastically bright blue legs and tail, and tells us that almost all the taste is in the head rather than the body. She also warns us off shrimps with black heads: they’re no longer fresh, she says.

We venture past the seafood stall deeper into the market, where Salazar Golding leads us to a smiling lady almost entirely submerged by enormous cuts of beef hanging from hooks. Tepui imports its beef from Brazil, Australia and New Zealand but the chef points out that this stall’s meat is good. “You can see it’s fresh because it’s red,” she says.

We end the tour at Salazar Golding’s favourite street food stall, near the southern corner of the west side of the market, where we enjoyed both fried and fresh chopped spring rolls, plates of greens, noodle curry and fresh shrimp as well as the staple ice coffee. These spring rolls, she says, are the best in the market. At $20 per tour including the meal, it’s certainly worth it to find your way around the market – and particularly to find those spring rolls.

Expat2cambodia runs its Food Market Tours once a month. Check www.expat2cambodia.com for dates and details.