I saw Heston Blumenthal the other night on TV with his roast chicken recipe, and I wish I hadn’t. His suggestions really worry me. Leaving aside his recommendation to brine the bird before roasting (because what we all need in our western diets, ladies and gentlemen, is more salt!), he advocates roasting the bird at 90 degrees centigrade (70, even, in a fan oven!) for several hours to a target internal temperature of 60C in the thickest part of the breast. While I have no doubt that this treatment results in a marvellously moist tender bird (it’s barely cooked after all!) the food safety implications of the process are pretty horrifying.
All raw meat is contaminated with bacteria. This is just a fact of life – after all, meat is dead animal, and animals have bacteria in and on them in life which are impossible to remove in the course of processing.
Poultry meat in particular is high risk. A UK study published in 2000 identified Campylobacter jejuni in 83.3% of supermarket chicken that they sampled. I would go as far as to say, I almost guarantee that any raw chicken you purchase will be contaminated with Campylobacter, Salmonella or E. coli, and the risks are probably higher with free range birds which aren’t raised in a sealed environment.
The reason we don’t all have food poisoning all the time is that cooking – the application of heat – is extremely effective in killing these pathogens. Here’s the problem – Salmonella requires a temperature of 60C for 10 minutes to be effectively killed. Campylobacter also needs to get to 60C, though it’s a bit more fragile so a minute or two should do trick. E. coli is more robust – but less common in poultry meat – and needs to be heated to 72C. The universal advice for safe cooking of poultry meat takes all of this into account and advises the thickest (and hence least heated) part of the meat should reach a minimum temperature of 75C for at least 10 minutes.
On these numbers you can see how Heston’s recipe might *just about* not be gastrointestinal suicide, but you would want to be very confident of your temperatures. The trouble is, any error in measurement – if your probe isn’t really in the absolutely coldest part of the bird – is going to read higher than the true lowest temperature, making it very easy to overestimate the minimum temperature and have parts of your bird below 60C.
To be quite honest, I don’t care how tender and succulent this roast bird might end up – it amounts to food hygiene russian roulette! I’ll be staying away from the Fat Duck, I think.
Please, if you want a wonderful succulent roast chicken, buy a good free-range bird with some good fat under the skin, add some lovely flavours in the cavity (I like a quartered lemon with some whole cloves of garlic and a handful of thyme), a little bit of salt and pepper on the skin with a couple of rashers of bacon if you fancy it, and then roast at about 180C to a safe internal temperature. Rest for 20 – 30 minutes before carving, and enjoy a tasty, succulent, and above all safe roast dinner!
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