What’s going on inside your ham and cheese sandwich?

Sometimes I feel that the common sandwich does not get its just deserts. We forget the stability it brings to millions during lunch hour all over the world. We overlook its extreme simplicity and do not honour the ways in which it brings families and communities together. Where would we be without a sandwich and a cup of tea?

The simple ham and cheese sandwich is a staple of many nations. France, Spain, Germany, Sweden and Ireland all have their variations on this exquisite wonder. Bread, ham, cheese and butter or olive oil – that's pretty much the basics. Of course many more items can be added, such as crisp lettuce or tangy pickles. The only limit is your imagination.

You would imagine that a basic ham and cheese sandwich has only four ingredients: bread, ham, cheese and butter. You would be wrong. At its simplest, the sandwich contains eight ingredients: flour, water, yeast, pork, salt, butter, milk and rennet (this is an enzyme used to split milk into curds and whey). Is this the type of sandwich you eat regularly?

Industrial sliced bread often has more than 20 ingredients. Their addition is not confined to the bread. I picked up a sandwich at a petrol station recently on the way from Galway to Dublin. Guess how many ingredients it contained: 48.

We may imagine we know what we’re eating but we don’t. Most ham we eat now is what is called “reformed ham”. It has all the odd cuts of pork glued together with all sorts of gels, gums, additives and preservatives. Sounds delicious, doesn’t it?

The only two ingredients you need to make ham is pork and salt. If your ham contains water as an ingredient (excluding the brine), then it’s probably been reformed with random bits of pork, water, salt and food glue.

To know what we are eating takes great difficulty. Why is it so hard to eat well? Eating well is eating food that has not been processed to an inch of its life. So the next time you buy a ham and cheese sandwich, turn the package over and read the ingredients. You might learn more about what is in your food.