With its ability to tenderise meat and create mouth melting morsels, sous vide is one of those fashionable cooking techniques beloved of top chefs and cookery show contestants alike.
But its use has landed one of the country’s top restaurants in hot water.
Hygiene inspectors who visited the two Michelin starred Glasshouse, in Mayfair, found that a crucial form logging temperature control of the restaurant’s sous vide machine had not been completed correctly.
It was one of a number of basic errors that led Westminster council’s inspection team to give The Greenhouse an embarrassingly low hygiene rating of just one out of five.
With a £110 a head tasting men and dishes such as Limousin veal with tamarind and Orkney scallops with samphire The Greenhouse promises a “unique dining experience” at the hands of its French chef Arnaud Bignon.
It will therefore come as a shock to many its customers to discover the inspectors were so concerned about the restaurant’s standards they decided it was in need of “major improvement”.
The Greenhouse has garnered rave reviews since it opened in Hay’s Mews in 1977.
The Tatler Restaurant Guide 2013 declared: “In an age of vulgarity, low taste and dirty dining, The Greenhouse is one of the most civilised places we know. It has an almost Zen-like tranquillity.”
The AA Rosettes Restaurant Guide said: “Arnaud Bignon is a chef who cooks from the heart, combining classical French techniques with contemporary ideas and not shying away from some out-of-the-ordinary flavour combinations at times.”
But Westminster’s inspectors found problems with “temperature control, structural disrepair, cleaning and maintenance of their documented food safety management system”.
They appear to have taken particular issue with the record keeping around at least one of The Greenhouse’s fridges and its sous vide equipment.
Sous vide is a method of cooking at low temperatures in which food is sealed in airtight plastic bags then placed in a water bath or steamer for longer than normal cooking times in order to tenderize it.
However care must be taken to avoid botulism poisoning, and health experts warn that women eating dishes cooked in this manner while pregnant expose themselves and their unborn children to risk from unpasteurized food.
Westminster council’s critical report comes after it was found that Michelin star kitchens tend to receive lower safety ratings than those of high-street chains.
Research by the Food Standards Agency (FSA) published earlier this year showed their rankings are generally lower than many familiar chain restaurants.
It found 83pc of high street chains were given the best rating of five out of five, compared to just 55pc of Michelin star restaurants.
The Food Standards Agency, which oversees the inspection system, says all businesses should be able to reach the top rating of five.
In their latest series of inspections, officials from Westminster gave the Michelin starred L’ Atelier De Joel Robuchon – described by critics as a “world class restaurant” – a rating of just two out of five.
They deemed that improvement was “necessary” to the cleanliness and condition of the Covent Garden building and the kitchen’s facilities.
Even the internationally renowned Le Gavroche, in Mayfair – run by Michel Roux Jnr – received a rating of only three out of five and was deemed to be “generally satisfactory” rather than “very good”.
Following their critical report The Greenhouse told Westminster’s inspectors that it’s staff have been reminded of “the correct procedure when checking equipment and to record any temperatures outside the critical limits”.
It also admitted that “a number of maintenance issues have now been dealt with”, including revising the safety settings and procedure for its sous vide.
The Greenhouse also told Westminster that since the last inspection “the establishment has been thoroughly cleaned and procedures are in place to ensure that cleanliness is maintained”.
The restaurant’s management added: “The conditions found at the time of the inspection were not typical of the normal conditions maintained at the establishment. The Greenhouse strives for the highest possible standards of food quality and safety.”
A spokesman for The Greenhouse said the restaurant had primarily fallen short on record keeping – with one member of the kitchen staff not completing forms correctly – and the safety of a wooden walkway in the garden, rather than in its preparation.
She said: “The Greenhouse is a two Michelin starred restaurant which has consistently delivered epicurean excellence at the highest possible standards. The rating by Westminster Council does not reflect our own internal hygiene or food safety standards. Retraining of staff in the affected areas has been undertaken and we would welcome another inspection.”
Christophe Piwowarczyk, general manager of L’Atelier De Joel Robuchon, said he rejected the inspector’s findings and has asked for the premises to be re-inspected.
“There is no problem at all with our standards of hygiene. I can guarantee you that,” he said. “Everybody is working very hard here to make sure our standards are as high as possible.”