The vast majority of people either don’t know or don’t care how the food they pull off supermarket shelves gets there in the first place. The story of how it gets there is both amazing but also disquietening. In our more romantic moods, we might imagine the chain of supply starting with a happy, hard-working farmer and ends with a benign, friendly supermarket but the reality is more complex. That supply chain involves knowledge from diverse fields such as biology (which is obvious) to information technology (which is less obvious). Sitting between the farmer and the supermarket will usually be at least one highly mechanised (and probably automated) factory and this
implies a lot of machinery. The rule of thumb is that the more processed the food, the more machinery is involved.
A small but crucial part of that supply chain is the inspection equipment looking for foreign bodies in the food. This aims to ensure the quality of the food dispatched from factory to distributor, supermarket or perhaps another factory higher up the processing chain. There are basically 2 types of inspection equipment:
- Metal detector
- X-ray
Metal detectors work on the principle of electromagnetic induction. This works well for ferrous metals in dry products, but works less well for certain grades of stainless steel or in wet or salty products. X-rays are a more more expensive inspection option. This technique is being increasingly used in the UK due to the limitations of metal detectors. A good X-ray will
be able to detect a small piece of glass in certain products where a metal detector would have no chance of detecting the glass.
An important contaminant in meat products is actually metal from three main sources, the first being obvious but the latter two will surprise a lot of people:
- Metal from the machinery used to process food
- Broken needles
- Lead shot
Whoa! Back up there, you say. Broken needles? Lead shot? How do these get in the food? Good questions and lets deal with them one at a time.
Firstly, since a lot of machinery is used in producing your TV dinner, this implies a lot of screws, bolts, washers, wires, meshes, cutting implements and so on. There may also be contaminants that are part of the product itself, such as the clip on the see-through plastic bag surrounding a loaf of bread – great on the bag, not so great inside the bread. So with all those moving parts, accidents do happen. A bit worrying, true, but logical to make sure a screw hasn’t worked itself loose and fallen into a mince pie.
X-ray image of dog food where one of the clips (found on the ends of the sausage) had found its way inside.
Needles are used on animals a great deal. There are innoculations when the animal is young and then later in their short lives to provide medicine when the animal gets sick. More disturbingly, however, steriods and antibiotics
are used regularly to produce more meat and faster. Pigs commonly squeal and jerk when injected, breaking off the needle which cannot always easily be retrieved.
The next contaminant, lead shot, is perhaps the most surprising of all.
While this is not common in Europe, in the Americas (both North and South) lead shot from game hunters is common. Indeed, the article that inspired this blog is about lead shot in elk. Killing animals is never clean and clinical in the best of environments and killing them in the wild even less so. Even if the hunter does intend to eat the animal, it may happen that the animal escapes after having been shot and only dies later of its wounds.
Even more surprising is lead shot from another source – animals shot not for sport but for thrills. While thankfully not commonplace, there are a significant number of examples of cows, horses (eaten in Argentina and other places) and pigs which have been shot with a non-lethal dose of lead pellets by young hillbillys out for a drunken laugh. When the animal finally does
get to the slaughterhouse, the meat supplier may not even know that the animal has a significant number of lead pellets buried in its body.
Hopefully the metal detectors and X-rays will find these pellets and prevent them from finding their way onto your plate.
Happily, not all aspects of food production are quite so disturbing! On your next trip to the supermarket, when you are about to pick up that cream pastry consider how it got there, smartly packaged next to hundreds of other enticing products. It certainly is food for thought.
Thank you to Alain Dekker for writing the text and supplying the image for this post.
Ouch Bron, this touches upon a certain (vagus) nerve.
Mechanically recovered meat etc. is a subject matter I know only too well for reasons of a personal nature
I somewhat doubt that anyone from DEFRA lurks around these here parts, but it if they did, I would be most interested for their candid views on blog posts like this.
When I was 16, I did some work experience at Birdseye-Walls, including the monitoring of the X-ray machine. My responsibility was to check the metre-cubed blocks of fish for foreign objects. I never spotted anything untoward, but the foreman told me all kinds of tales about what nearly ended up in your fish fingers.
Gosh Graham, Am really sad to hear about your brother. CJD is definitely one of those big serious subjects and it looks like you are doing some really good work on this front.
Matt: I was amazed at how much of our food is analysed by x-ray machines – it is really good that there is this check before the food reaches our tables. They are also able to do some neat things with estimating the volume of products as well as checking that all of the spaces in a chocolate box contain a sweetie.
No worries Bronwen,
Great article by Alain and certainly much more interesting than the ‘usual’ slug found in lettuce articles that do the media rounds.
The rule of thumb is that the more processed the food, the more machinery is involved. Precisely.
Whilst one does consume some processed food, I much prefer to prepare my own meals (no Scottish jokes!!) and where poss., use local produce.
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Here’s an interesting pdf from the USDA that I just found. Food for thought indeed !!
(My USDA research contacts have been really open and helpful over the years).
Whilst one does consume some processed food, I much prefer to prepare my own meals (no Scottish jokes!!) and where poss., use local produce.
But as Bronwen/Alain points out, even that which we consider ‘unprocessed’ is in itself processed – vegetables picked, trimmed and bunched, meat killed, cut and carved, and flour picked, chaffed, ground and weighed.
Very true Scott.
The point that I was echoing was:-
The rule of thumb is that the more processed the food, the more machinery is involved.