Recent food scares may have put some caterers off the idea of serving pâté or parfait made from chicken liver or other offal, but it's perfectly possible to use these ingredients safely as long as careful cooking and hygiene practices are followed. Michael Raffael reports
Chicken liver parfait can be bad news. It was at the centre of a recent case of food poisoning when 46 wedding guests at Macdonald Frimley Hall in Camberley, Surrey, were affected (Caterer and Hotelkeeper, 22 February, page 6). The hotel had to foot a £72,000 bill in fines and related costs. This wasn't a rogue operation, but a business with the highest Food Standards Agency (FSA) rating.
Poultry livers have a "history". They used to be left packaged inside the carcass as a part of the giblets. Then the EC legislated and abattoirs had to remove the livers and sell them separately.
Before caterers and restaurateurs single them out as bad guys, they aren't potential targets for another food scare. They can represent a health hazard, but so can any food.
The most recent food poisoning incident to hit the headlines was at Noma in Copenhagen: 63 diners were taken ill with Roskilde Sickness, a variant of the norovirus, which causes vomiting and diarrhoea, after eating at the world-famous restaurant last month. Meanwhile, It was the norovirus that closed the Fat Duck in 2009.
Before that there was E coli 0157 in pies, before that lysteriosis in soft cheese, and the salmonella story, with or without Mrs Curry's eggs, has never gone away. There's always something to worry about.
None of these bacteria or viruses (all heavily publicised) are as widespread as campylobacter. Its incidence is rising at a time when salmonella is reducing as a source of food poisoning. There are around 50,000 reported cases a year, but the FSA estimates that the true figure is 371,000. In 2009, it was responsible for 17,500 hospitalisations and 88 deaths.
Cooking methods and equipment have been changing: think slow cooking, low-temperature cooking, Thermomix, water bath and the inexorable spread of vacpacked (sous-vide) preparation. These don't alter the basic rules of food safety. They do put more pressure on kitchens to implement strict hygiene regimes that minimise risks.
The trend for cooking food to a specific core temperature - rather than relying on a sense of touch, taste and eye - started more than â¨30 years ago. When the early experiments relating to sous-vide cookery took place, chefs consulting to the three-Michelin-starred restaurants suggested that the ideal temperature for foie gras terrines was 65Â°C. According to â¨Justine Fuller, principal environmental health officer of Surrey Heath Borough Council, which brought the prosecution against Frimley Hall, livers ought to be held at this temperature for 10 minutes (see FSA panel, below).
It's a temperature that has advantages. Most harmful bacteria don't multiply above this level. It allows chefs to cook a pÁ¢té or terrine that is still pink. This isn't a pasteurising, thermising or sterilising process. As such, it's critical that chilling and storage follow rapidly. It's also vital that there's no cross-contamination via knives, chopping boards, any containers or serving dishes.
Every restaurant and every customer has to decide what a manageable risk is. Most cheese-lovers, for instance, wouldn't want all soft cheeses to be pasteurised because there's a tiny risk to a few pregnant women of catching lysteriosis. Gastroenteritis can put some sufferers into hospital (mainly, children and the elderly). Most, though, have mild symptoms that clear up without treatment.
However, banqueting or function managers should ask themselves whether it's such a good idea to put a chicken liver parfait on the menu when 500 guests are sitting down to eat.
CHECK IT OUT
Sourcing It's the traceability thing. Chefs need to be able to trust their suppliers and those who deliver to them. What's the record of the poultry farm from which the livers come?
Washing When washing chicken livers, use chilled or iced water (preferably chlorinated). This in itself isn't risk-free and should never be done in a sink because any splashing could add to the cross-contamination risk.
Chill temperatures From delivery to prepping the livers and from cooking to service of a parfait, keep produce and product at safe temperatures. (From a taste point of view, it's better to allow the finished parfait to come out of the fridge for a few minutes before service.)
The basics Wash and dry hands thoroughly (surgical gloves may sometimes be an option). Staff suffering from any sort of stomach bug shouldn't be in contact with food, whether waiting or cooking.
Minimise risks of cross-contamination Use separate chopping boards and, within reason, separate utensils and storage containers. Bear in mind that the livers are more likely to be a problem than, say, a turnip.
From Simon Christey-French at London's the Chancery
Campylobacterâ¨ It's often linked to under-cooked poultry and people working in abattoirs can also become ill as a result of contamination. It's arguably the most common source of food poisoning.
"Campylobacter is the commonest reported bacterial cause of infectious intestinal disease in England and Wales. Illness is characterised by severe diarrhoea and abdominal pain. Under-cooked meat (especially poultry) is often associated with illness, as is unpasteurised milk and untreated water. The majority of infections, however, remain unexplained by recognised risk factors for disease."
(Health Protection Agency HPA website)
Salmonella â¨This used to be the big news story where food poisoning was concerned and its link to eggs (actually decreasing as a problem) explains why many caterers use pasteurised egg for mayonnaise. However, all food, including vegetables - fresh, frozen or thawing - can be infected with salmonella bacteria.
Listeria â¨Listeriosis tends to affect the elderly or those with a weakened immune system. Many â¨people carry the bacteria without any symptoms. Any processed foods can be contaminated - eg, ready meals, soft cheese, smoked fish or pÁ¢tés.
Norovirus â¨As its name suggests, this is a virus, but it can be transmitted by contaminated food. Norovirus is highly infectious. Outbreaks are common in semi-closed environments such as hospitals, nursing homes, schools and cruise ships. Transmission is person to person or through contaminated food such as shellfish.
THE FSA POSITION ON COOKING TEMPERATURES
The agency advises that liver, kidneys, and other types of offal should be handled hygienically to avoid cross-contamination and cooked thoroughly until they are steaming hot all the way through, reaching a core temperature of 70Â°C for two minutes or equivalent. The equivalent heat treatments are:
- 65ÂºC - 10 minutes
- 70ÂºC - Two minutes
- 75ÂºC - 30 seconds
- 80ÂºC - six seconds
Tufted duck and chicken liver parfait, red wine poached quinces, pickled walnuts
For the tufted duck and chicken liver parfait 150g banana shallots, diced
625g unsalted butter
Maldon sea salt and freshly cracked black pepper
1 clove of garlic, crushed
1tsp chopped fresh thyme
1tsp coriander seeds, crushed
250g tufted duck meat, cut into even-sized pieces
500g chicken livers
For the red wine jelly 200ml good-quality red wine
1.5g agar agar
For the red wine poached â¨quinces 400g firm but ripe quinces
Maldon sea salt and freshly cracked black pepper
5 juniper berries, crushed
100g caster sugar
200ml good-quality red wine
To serve Baguette
Method To prepare the parfait, preheat the oven to 150Â°C. Fry the shallots in 50g butter with seasoning until transparent. Add the garlic, thyme, brandy and crushed coriander seeds, melt the remainder of the butter and add to the shallots. Leave to cool slightly.
Blend the duck and chicken livers until puréed. While blending add the cooled shallot and melted butter mix, season and blend to emulsify. Pour the mixture into a terrine mould, place in a bain-marie, and cover. Cook the parfait in the preheated oven for 45 minutes. Cool over ice. Once chilled, blend the parfait until silky smooth and leave to set in the fridge for one hour before serving.
To make the red wine jelly, mix all the ingredients together in a small saucepan, bring to the boil and simmer for one minute. Pour the mixture into a small square plastic container and leave to set - do not move until completely set.
For the red wine poached quinces, preheat a water bath to 75Â°C. Peel and core the quinces, cut into Â½cm thick wedges and season with salt and pepper. Vacuum the crushed juniper, quince wedges, red wine and sugar. Cook in the water bath for 30 minutes, or until tender but not too soft. Cool over ice.
To serve, scoop a quenelle of parfait on to a slice of toasted baguette, and place on the plate. Garnish the plate with dollops of the jelly, slices of red wine quinces and pickled walnut pieces, then finish with a few micro leaves and rapeseed oil. Serve immediately.
Heston Blumenthal's meat fruit
For the chicken liver parfait
(This recipe makes one 26cm x 10cm x 9cm terrine)
100g shallots, finely sliced
3g minced garlic
15g sprigs of thyme, tied with string
150g dry Madeira
150g ruby port
75g white port
18g table salt
400g chicken livers (trimmed weight)
300g unsalted butter, melted
For the mandarin jelly
45g leaf gelatine
500g mandarin purée
0.4g mandarin oil
1.5g paprika extract
Place the shallots, garlic and thyme in a saucepan with the Madeira, ruby port, white port and brandy. Set aside to marinate for 24 hours. Heat the marinated mixture until nearly all the liquid has evaporated, stirring regularly to prevent the shallots and garlic from burning. Remove from the heat and discard the thyme.
Preheat the oven to 100Â°C/gas mark 1/4. â¨Fill a bain-marie with 5cm water and place in the oven. Preheat a water bath to 50Â°C.
Sprinkle the table salt over the livers and put them in a sous-vide bag. Put the eggs and the alcohol reduction in a second sous-vide bag, and the butter in a third. Seal all the bags under full pressure, then place in the water bath for 20 minutes. Remove the bags from the water bath.
Combine the eggs, alcohol reduction and meat in a Thermomix and blend until smooth at 50Â°C. Slowly blitz in the butter and blend until smooth. Pass the mix through a fine sieve using the back of a small ladle.
Pour into a terrine dish and place in the bain-marie, then cover the bain-marie with aluminium foil. Cook the parfait until the temperature in the centre reaches 64Â°C.
Remove from the oven and allow to cool. Refrigerate for 24 hours before serving.
To make the mandarin jelly, place the gelatine in cold water to soften. Gently heat the mandarin purée and glucose in a pan to combine. Add the softened gelatine and stir well until dissolved.
Remove from the heat and add the mandarin oil and paprika extract and stir well. Pass the mixture through a fine sieve and reserve in the fridge until required.
To make the fruits Using a spoon, fill dome moulds with parfait, ensuring there is enough pressure to create a completely smooth surface. Level off the tops so that they are flat, and cover with clingfilm. Gently press the clingfilm directly on to the surface of the parfait. Place in the freezer until completely frozen.
Gently de-mould the parfait domes. Place on a board with the flat sides facing upwards. Very briefly run the flame of a blowtorch over the flat side, being careful only to just melt the surface of the parfait. Join two halves together and compress using a square of clingfilm. Wrap well in clingfilm and place back in the freezer until required.
Gently push a wooden cocktail stick into the middle of the rounded surface and re-wrap until all the parfaits are complete. Gently melt the mandarin jelly in a saucepan and allow to cool to room temperature. Remove the clingfilm and dip each ball of parfait into the jelly and stand the sticks, covered in clingfilm, into a piece of Oasis (the green material you get in florist shops to help the flowers stand up). Place in the fridge for a minute, then repeat the dipping process.
Dip three times, then gently remove the cocktail stick and place the balls on to a tray covered in clingfilm. Place a lid over the tray and leave in the fridge to defrost for at least six hours.
Once defrosted, gently push the top of the ball using your thumb to create the shape of a mandarin. Place a stalk and leaf in the top centre of the indent to complete the fruit.