For people who care about their food

A good egg? Part One: salmonella

Brown hen's eggs on a cardboard trayWith the news of a salmonella outbreak across the UK and Ireland, my thoughts were jerked back to the late 1980s and the furore about salmonella in British eggs. Remember the then junior Health Minister “Eggwina” Currie saying that most British egg production was infected – and then being forced to resign because officials in the Department of Health were unable to substantiate her claim?

The latest outbreak doesn’t appear to be egg-related. All the same, the outbreaks of the late 1980s have led many people to associate salmonella with eggs. Even today, people often wonder whether it’s safe to eat raw or lightly cooked eggs because of fear of salmonella poisoning.

We’ll be looking at the closely related question of how eggs are produced soon. For now, let’s concentrate on the health issues surrounding the eggs themselves.

You’ll have noticed that a little red lion with a crown started to appear on British eggs a decade or so ago. This isn’t the first time that the lion mark has been used; the last time was for 15 years from 1956 to 1971, when the Egg Marketing Board used the symbol to boost flagging sales of eggs.

The British Egg Information Service revived the Lion Quality Mark in 1998. The new Lion Mark shows that the eggs meet certain strict standards. Crucially, all pullets destined for egg-laying flocks have to have been vaccinated against salmonella if their eggs are to bear the Lion Quality Mark. The farms also have to be independently audited for food hygiene standards, and the eggs have to bear “Best before” dates and identifying marks to enable their farm of origin to be traced.

All the evidence seems to show that the scheme’s been a remarkable success. Incidences of salmonella in the UK’s laying flocks were down to just eight per cent in 2007, against an figure of more than 50% in several EU countries. As for eggs themselves, a test of 28,000 UK-produced eggs by the Food Standards Agency in 2004 showed that not one of the eggs contained salmonella.

Nevertheless, it’s still worth taking precautions when handling eggs. A few key points to remember:

  • The salmonella bacteria can live on the shell as well as inside the egg (both the white and the yolk) – so wash your hands after they’ve come into contact with any part of the egg
  • Salmonella can pass to and contaminate surfaces that eggs come into contact with – so keep eggs separate from other foods in the fridge, and clean any working surfaces, containers and utensils that come into contact with eggs or their packaging
  • Cooking will kill the bacteria, but only if it’s done for long enough!
  • If you’re cooking eggs by themselves – by whatever method – both the white and the yolk must be cooked until they’re solid to eliminate any risk of infection
  • If you’re using eggs as an ingredient in another dish, the dish should be cooked until it’s piping hot throughout

The Food Standards Agency recommends that raw or lightly cooked egg shouldn’t be eaten by the elderly, very young children, the sick, or pregnant women. (You can find out more details of their advice from the FSA website.)

This still leaves the question of what to do when you’re making something that requires raw or partly-cooked eggs, such as mayonnaise, hollandaise and béarnaise sauces, or even soft-boiled eggs. FSA advice is that this is a personal choice, but that you should be aware of the risk of food poisoning.

So if there’s a risk, how are professional caterers able to make their own mayonnaise and egg-based sauces? Answer: they use pasteurised egg. Like pasteurised milk, pasteurised egg has been heated to a very high temperature for a very short period of time, killing bacteria without cooking (and thus without altering the taste of) the foodstuff. Pasteurised egg is almost identical to raw egg, although the white is slightly opaque.

Unfortunately, it’s not so easy to find pasteurised egg in retail outlets. A BBC News story back in 2000 reported that scientists had discovered a way to pasteurise eggs in the shell, and enthusiastically predicted that the eggs could be on supermarket shelves the following year. But, according to the BEIS website, pasteurised egg is still only available in commercial quantities and not through supermarkets – although the FSA says that it’s available in some supermarkets.

So if you fancy dipping soldiers into your egg yolk at breakfast, be aware that they might launch a surprise attack on you later…

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