The male staff at Coogee's Melonhead have been known to exchange bird calls While blending strawberries or squeezing oranges. Not because they're amateur ornithologists but because it allows them to speak in code about their customers.

"Yeah, we used to make a few whistles," admits the shop's co-owner, Marty Papadopoulos. "One was like an owl. That would be for a girl that had been out all night. Another was an eagle's screech. That would be for a girl you'd reckon was pretty feisty."

Welcome to the secret life of the juicers.

Melonhead, a family-run shop that sells juices, smoothies and assorted edibles, is a short walk from Coogee Beach. A lot of its customers come straight from the sand, including fitness freaks perfecting their abdominals and sun bunnies perfecting their melanomas.

"A lot of girls come up in bikinis," Papadopoulos says. "That makes it easier working here. Yeah, the staff meet a lot of girls. A lot of relationships started in this shop."

Melonhead has had a secret double life as a matchmaking service since opening its doors on New Year's Day, 2001. The 100-year-old terrace was formerly the home of an oily takeaway joint; Papadopoulos says it took four days to clean off all the congealed grease.

The timing was good: Melonhead opened just as healthy food was catching on and wheatgrass shots and organic produce were becoming fashionable.

"When we opened, we'd never done anything like this before," Papadopoulos says. "We had no idea. I was 19. Actually, I was a bit out of it as well, because I'd been out the night before. I've never done that again. I think I've been to bed before 12 o'clock every New Year's Eve since. New Year's Day is really busy. There are lots of families out.

"I opened up the store with my two sisters, and Dad was helping out a lot, and Mum as well. That went on for a couple of years but it's hard working with family at times. I got into a bit of an argument with Dad one day and threatened to join the French Foreign Legion. I was ready to pack up and go. Instead, I joined the army for a year."

Looking at the trays of juicy, ripe fruit, it's hard to imagine the family tension. Among all this sweetness? In the cabinet, fruit salad and muesli jostle for space with chopped watermelon. Nearby are the chocolate-covered strawberries. In families, as in fruit juices, it seems, some combinations just don't mix.

After Papadopoulos was medically discharged from the army, he returned to the business in 2003 and took it over from his sisters. He now runs it with an old friend, Andrew Lumb.

Their day starts early. "Normally I get up about quarter to five and take the big van to Flemington Markets," Papadopoulos says. "Dad used to work down the markets for 40 years, and he used to take us kids down there when we were 10 so I know some of the guys."

He returns in a van crammed with strawberries, mangoes, bananas. A crash would not be pretty.

It often it isn't pretty on Coogee Bay Road when the shop opens at 6am, thanks to the drunk and dishevelled.

"When we open, we see a lot of the stragglers. It's pretty bad in the morning with the rubbish everywhere. It's a totally different place at five o'clock in the morning compared to 10 in the morning. You wouldn't want to move here if you came here at five."

That's one of the petty hassles of the job. Another is staffing: employees have an uncanny habit of calling in sick on sunny days. Another is the preparation. There are only so many lemons you can chop before you want to stomp them into a pulp. There's also the lack of summer holidays.

"Your friends go away on holiday and ask if you're going to come away. But no, we're here in the shop. Normally in the wintertime we try to take a week or two off."

That's the funny thing: the juicing business is as seasonal and weather-dependent as its fruit. The busiest days are sunny summer Sundays; the quietest days are rainy winter Wednesdays. Papadopoulos watches the Weather Channel every afternoon to get an idea of how much fruit he needs to buy the following morning.

"In the wintertime you don't make money. You just open to pay the rent, then wait for summertime to make money."

And with the coming of each summer, Papadopoulos and his male colleagues devise a new code to enable them secretly to discuss their customers. So what is the code this year? What's the signal when a cute customer walks in? Papadopoulos just smiles. He won't say.