I cycled through the hot, dusty streets around Battambang, Cambodia, for a few hours looking for the old Pepsi factory, when I realised I was looking straight at it.

I’d sat down at a road-side stall selling green mango salad, and was ferreting through the ice box for a second cola, when I turned round and saw the same logo, but this time faded and sorry-looking and without the “Max”, on a disused building across the road.

The place was massive. I pushed open a side-door and an old caretaker waved me away. I offered him some dollars, but still he wouldn’t let me in. So I took a long shot of some old Pepsi bottles that had survived the plant’s sudden closure when the Khmer Rouge seized power in 1975, and walked back out into the yard.

A Pepsi plant was never going to get an easy ride from Pol Pot’s thugs, who’d thought nothing of destroying their own temples, libraries, and schools to cleanse the country of its perceived political enemies, let alone a brand associated with American capitalism. It stood out like a bucket of KFC at an anti-vivisectionists’ meeting.

I was amazed how much of it was still standing. I went round the back, but there was nothing to see apart from a couple of cement water tanks, so I returned to the old man, and handed him another note, and this time he relented. I couldn’t go into the dusty office block, but he opened a gate and let me into the warehouse.

“But no machine,” he kept saying, as he stuffed the notes into his back pocket.

It looked like a film set from an Armageddon B-movie, with shell damage and bullet holes letting in shards of sunlight. The place had stopped in time like an old watch. There was the odd broken Pepsi bottle buried in the rubble and debris. But other than that, a series of switches was pretty much all that remained of the 1960s machinery.

Back then, Coca Cola had reportedly signed a deal with Bangkok to only allow its cola to be manufactured in Thailand, so Pepsi set up the bottling plant on a ferry point in Battambang, near the Thai border, so that it wouldn’t miss out on the Thai market.

I took a few more photos, and had a last stroll around the rubble, watching my step for snakes, and then returned to the old man. He was padlocking the door to the office block. I tried another bribe, but he just shook his head and smiled.

I rode back out and stopped at the stall for another drink. I ordered a green mango and smoked fish salad, and chatted away to the woman as she made it.

She told me the old man and his family were paid to sleep in the factory grounds to keep out visitors. She said the government was planning to turn the whole thing into a huge fresh water-producing plant at some point, but they’d been saying that for years.

She began breaking off pieces of smoked fish and pounding them in a large, wooden pestle and mortar.

The fish was from the prahok market a few miles up the river. I’d been up there the day before to watch them make it.

It’s soaked in brine, and then grilled over smouldering wood for up to eight hours. It’s hard and chewy and full of bones, and has a strong but pleasant taste of that magical, hot-smoked combination of salt and burned wood.

She added three whole red chillies and three peeled garlic cloves and continued pounding away for another minute. And then she suddenly stopped, and frowned at me as though she’d just thought of something.

“But this one we only eat with rice, and you eat only alone? It’s very sharp! It’s very hot, and maybe you get diarrhoea?” she said.

She was right, as I would learn. It was hot. And sharp. Heat-wise, it was as spicy as any som tam papaya salad you’d get in Thailand, even in the notoriously fire-eating Isaan area. But my word it was good.

She continued pounding, and then sprinkled in half a teaspoon of sea salt, a teaspoon of sugar, and about the same again of MSG before I could stop her.

She worked away with a hand-sized mandoline shredding long strips of green mango into the mortar, then mixed it altogether and pounded the salad lightly. She spooned it on to a small plate and garnished it with three roughly-chopped thorny coriander leaves.

“We can use the green mango, but very sour, but when we put the grilled fish, not,” she said, reminding me again of the Cambodian custom of balancing flavours.

I’ve made the recipe again, and it really is good, but very hot, so lessen it to just one red bird eye chilli if you don’t like the heat.

You could always brine and then barbecue the fish yourself over smouldering wood, but Rick Stein recommends the far quicker method of skinning a couple of smoked mackerel fillets, flaking the meat, and deep-frying it in a skillet filled with an inch of oil for a minute or so, until the fish is golden-brown and crisp. You then scoop out the fish pieces and let them drain on a piece of kitchen paper to soak up the oil before pounding them to begin the salad.

In my version, I missed out the sugar and MSG, and instead balanced the sweetness and chemicals with a splash of Pepsi at the end. It was really good, and a fitting reminder of that old soda plant and the days I spent cycling to the pre-Angkor ruins near Battambang that had also survived the Khmer Rouge’s rule.