Tina Chunguene, 30, a divorced mother of two, says the habit was passed down to her by her grandmother and her mother. 'Now I really enjoy it,' she says, as she wanders through Xipamanine market in search of a salty variety.

Another earth lover said it helped her 'avoid sickness and stimulates the taste buds. It's just like chewing bubble gum!'

The craving has sparked a thriving business that is employing people in every phase of production - from digging, drying and refining the earth to packaging and transportation.

For vendors, the profits are handsome, even factoring in transport and additives.

And at only around 150 meticais, a 50 kg bag of earth that yields thousands of portions doesn't exactly cost. ...the earth.

With unemployment in Mozambique officially listed at around 60 percent, and the HIV/AIDS pandemic killing many breadwinners, women traders say the business helps keep food on the table.

For local government too, the business is a boon as the vendors pay market taxes to the municipality.

It's still a cottage industry however - operated mostly out of the urban backyards.

In Maputo's impoverished Mafalala neighbourhood, mounds of unrefined earth are scattered on top of raffia sacks in the workshop of Dona Joana, a producer.

Joana, 60, only adds salt but some producers add soap, which acts to cleanse the customer's digestive system, she says.

The practise is not just limited to Mozambique. Little packets of earth are also sold in markets in neighbouring South Africa to a mixed clientele of locals and Mozambican migrants.

'It's entrenched in the culture,' a doctor at Chris Hani Baragwanath Hospital in Soweto township who did not wish to be named said, adding: 'It's not really harmful unless in very big doses but infection (from parasites) is certainly a risk.'