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It sounds more like the recipe for a good pasta sauce, but scientists have created a new edible coating that extends the shelf-life of cheese from seafood, rosemary and oregano.

The transparent film uses extracts from the shells of crustaceans with oregano and rosemary oils to keep cheese from drying out and help prevent the growth of fungus and bacteria.

Tests have shown that the coating is as effective as anti-fungal chemicals and plastic coatings that are currently used to protect some cheeses by the dairy industry.

Tronchon cheese was coated (labelled queso Tronchon recubierto) with a combination of chitosan, which is extracted from crustacean shells, and essential oils from rosemary and oregano

The researchers claim that the new coating will be particularly useful for soft cheeses like ricotta but could also help prevent mature cheeses like brie and blue cheeses from spoiling.

While helping to prevent the cheese from going off, it is also completely edible and so will not need to be removed like some artificial rinds that are used.

Professor Chelo González, a researcher at the Institute of Food Engineering for Development of the Polytechnic University of Valencia, said: 'The most common causes of deterioration are excessive surface dehydration and the growth of micro-organisms such as fungus or yeasts.

'These produce a strange flavour or odour, a slimy texture and a significant visual alteration.

'Using a natural and edible product reduces the fungal problems and controls the weight loss during the maturing.'

Currently cheese makers use a combination of anti-fungal chemicals like pimaricin and a polyvinyl acetate plastic to protect the cheese. 

However, in some products this is often not suitable and means consumers need to remove the coating before eating.

Professor González said the new coating was an alternative to this approach, which helps to give commercial soft cheese a lifespan of about 21 days in cold storage.

Her team have been working with cheese makers in Valencia to develop the new coating and have tested it on the distinctive semi-soft Spanish Tronchon cheese.

The coating is made from chitosan, a type of fibre that can be made from the shells of crustaceans such as shrimp and crabs, that provides a physical barrier around the cheese that is safe to eat. 

Soft cheeses like Camembert can often spoil as they dry out and are prone to be attacked by fungi, but scientists at the Polytechnic University of Valencia believe their new edible coating can protect it

Taste tests on the new edible coating, which was used on the semi-soft Spanish Tronchon cheese made from a blend of milk from cows, goats and sheep, showed it did not affect the taste of the cheese itself

Essential oils from oregano and rosemary have high antimicrobial activity and so help to prevent the growth of fungi and bacteria on the cheese.

Professor González's research, which is to be published in the International Journal of Food Studies, showed that oregano oil was the most effective at inhibiting the fungal growth.

By tweaking the concentrations of the oils they were able to obtain the anti-fungal activity without the oils altering the flavour of the cheese.

Professor Chelo González (left) has been working with cheese makers in Valencia to develop the new coating to extend the shelf life of soft cheeses like Spanish Tronchon cheese (pictured above)

Taste tests with 100 panelists gave higher scores for cheese coated with essential oils for taste and odour attributes in comparison to uncoated cheese, Professor González said.

She added the coating could prove useful in helping to decrease the growth of fungus on the surface of cheese during the maturing process, which can enter into the pieces when they have pressing faults or fissures. 

She said: 'In this case, applying the coatings that we have developed will reduce the proportion of product losses in the cheese factories and therefore the important economic losses that this implies.'