Tailoring for top Milan fashion houses, pirating of DVDs and handbags, fishing of endangered bluefin tuna and brewing genetically-modified beer are all part and parcel of Italy's thoroughly modern Mafia.

Coldiretti, the Italian farmers' union, reported this year that the Sicilian Mafia is adding flavouring to colza oil, often used to lubricate machinery, before re-labelling it as olive oil. Hundreds of fake Parma hams and cattle falsely branded as gourmet Chianina breed are seized by Italian police each month. And the Neapolitan underworld is in expansive mode, it seems, with reports emerging that the Camorra are recruiting increasing numbers of children, since under-14s are safe from prosecution.

A recent report by Italy's small business group estimated that the Mafia is the biggest business in Italy, with organised crime netting Mob bosses the equivalent of more than £63bn a year, or 7 per cent of the country's gross domestic product.

Download the new Independent Premium app Sharing the full story, not just the headlines

Italy's four biggest crime gangs – the 'Ndrangheta in Calabria, the Sacra Corona Unita in Apulia, the Neapolitan Camorra and the Cosa Nostra in Sicily – are increasingly branching out into previously legitimate industries such as food, researchers discovered. Pirated handbags and DVDs accounted for £5bn of Mafia income and the food industry netted the underworld £5.2bn, according to Tano Grasso, the head of Italy's anti-racketeering commission.

Roberto Saviano, the investigative journalist in Naples who wrote a bestselling book about the Camorra, disclosed how leading fashion designers' companies regularly outsource orders to sweatshop tailors controlled by the Camorra in Campania. Mr Saviano did not name any of the designers but he revealed how big fashion houses supply competing Mob tailors with raw materials. The skilful underworld tailors win the contract while the others are allowed to flood the market with "counterfeit" clothes tailored to specifications received directly from the Milan or Rome firms seen as spearheading some of Italy's most prestigious exports.

Mr Grasso said that in Naples the Camorra runs 2,500 illegal bakeries, while the Cosa Nostra and the 'Ndrangheta have been quick to spot the profits to be made from illegal fishing, especially of endangered bluefin tuna.

Campania has long been the capital of the "eco-Mafia" in Italy. Millions of tons of industrial and urban waste are trucked into the region and dumped illegally each year, poisoning farmland and contaminating public waste-disposal sites. The Mafia hides behind apparently legitimate waste-disposal firms, which appeal to unscrupulous companies tempted to remove their waste cheaply.

Often the Camorra digs illegally for sand, leaving gaping pits in the countryside. It then dumps toxic waste in those holes. Then it uses the sand dug earlier to build illegally over the toxic waste, or wins government contracts to sanitise the contaminated areas.