When the latest food scandal broke, a small epidemic of holiday anecdotes followed.

Someone would remember the little French village with the horse's head sign hanging over the door of the boucherie chevaline. Someone else would tell of the Routiers joint where they forgot to ask about the origins of the entrecote.

Been there and – thanks to near non-existent French – done that. A line was drawn, for entirely inconsistent reasons, at horse sausage, but the rest of what you hear is true enough. If you are not squeamish or hypocritical, the flesh of a four-legged friend should do no harm. It's less fatty than beef and, as everyone remembers, slightly sweet.

All such tales have been beside the point, however. A French horse butcher will give you exactly what you ask for. If your English-speaking inhibitions go deep, avoid the shop, or read the restaurant menu carefully. You will run no risks. As we now know, a cheap processed burger or beef-type lasagne ready meal comes with no such guarantees.

The chances remain that the 100% horse content identified in some Findus lines will do no-one any harm. The possibility that a horse anti-inflammatory called phenylbutazone ("bute") might turn up is worrying, but not critical. Emerging evidence of an international criminal conspiracy to adulterate food for profit is serious, but not of itself a threat to health. We've had worse scares.

The fundamental issue is this: after years of scandals and reassurances, we still can't trust the food chain. Non-existent testing, minimal content controls and compromised labelling leave us wondering, yet again, about the processes involved in processed food. This time, to general British disgust, it's "just" horse. But what do we really know? The facts as they stand are the opposite of encouraging.

Start with the supermarkets. They make great play, these days, of the strict controls they claim to impose on their suppliers. How has that worked out? The list of retailers rushing to shut the barn door after the horses now includes Tesco, Lidl, Aldi, Iceland, Sainsbury's, Asda and the Co-op. Burger King, among the fast food outfits, has uncovered traces of nag. Some of the actions by some chains have been precautionary, but the testing has come too late.

So how about the Food Standards Agency (FSA)? Presumably it still does what it says on the tin? Not exactly, not in England. When the Coalition Government came to power there was a fear the FSA would be abolished entirely. Instead, it lost some of its powers to the English agricultural department – the food industry's traditional friend – and some to the department of health.

The upshot was that a UK-wide system for checking whether foods contain what the labels say they contain fell victim to "reorganisation". Local authority budget cuts have meanwhile dealt a blow to trading standards enforcement. In Ireland, inspectors employ DNA tests, including tests for horse, when checking processed "beef products". British testing does not – or rather, did not – involve a check for equine DNA.

The paranoid among us might therefore feel entitled to wonder what other treats have infiltrated the food chain. If crooks are at work putting horse in the family lasagne they have presumably calculated that real harm to public health is in no-one's interest, least of all their own. But what happens if adulteration is attempted by criminals who are too stupid to care, or by people who have real malice in mind? At what point would our standards agency catch on?

Food labelling is a scandal in its own right – who truly understands a full list of processed contents? – but in this context it is, to mix food groups, a red herring. The scandal is not that someone has failed to pencil "Dobbin" on the labels of the filler used to bulk up economy burgers. What ought to worry us is that we don't truly know what we're eating, and can't rely on those responsible for the food chain for trustworthy information.

It comes back, time and again, to processed food, added value for retailers, economies of scale, pitiful standards (even when they're enforced) and household incomes. You could make your own burgers or lasagne; neither would tax the motor skills even of a newspaper columnist. But try doing it at a price to match those frozen bargain basement economy "meat product" offerings. It can't be done.

How many people know, in any case, that there is a world of difference – entirely legal and above board – between meat and a "meat product"? How many could then say what the difference is, as defined by the Meat Products (Scotland) Regulations 2004? Considering what's allowed, it seems almost comical to quibble over the presence of someone's erstwhile little pony.

By European Union agreement, meat is defined as "skeletal muscle with naturally included or adherent fat and connective tissue". Mechanically recovered meat is these days excluded from the definition, while items such as liver, kidney or heart have to be labelled as such. Nevertheless, beef remains beef if it is composed of up to 25% fat and 25% connective tissue.

Meat products, on the other hand, can contain mechanically recovered meat, or flesh "from any mammalian or bird species recognised as fit for human consumption". Among the things you needn't mention about your product are additives, "ingredients added solely to impart an odour or taste", any starch or vegetable protein added only for "a technological purpose", or added water amounting to no more than 5% of the weight in cooked cured meat and 10% in uncooked cured meat.

The regulations nowhere define "technological purpose", but the upshot is that an economy burger becomes an item containing 47% meat "or, as the case may be, cured meat from other species or other mixtures of meat". A true pork sausage must contain at least 47% pork, but a cheap version can get by with 30% of meats in various guises. A Scotch pie need involve only 10% "meat".

The practices involved are safe, no doubt, and certainly legal. Many producers exceed the minimum standards as a matter of course. But if these standards are taken to be good enough, Europe-wide, to safeguard frugal ordinary families, who is surprised when someone tries to profit by betting on a bit of horse? We are encouraged to live on processed food from boxes with pretty pictures when even the legal contents bear no examination.

So the factory production of "meat" is open to abuse: who'd have guessed? So routine testing has fallen into abeyance and politicians are shocked. So we beat ourselves up once again over the things we eat or can afford to eat. Perhaps, instead, we could look seriously, just for once, at the marketing efforts of the food industry as it inculcates habits and addictions for the sake of the added value – meaning the sheer profit – to be had from well-disguised processed animal parts.

The discovery of an international criminal conspiracy will be convenient to those who are supposed to manage the food chain. That the horsemeat scandal is not remotely equivalent to BSE, meanwhile, does not alter an underlying attitude. It holds, still, that what the consumers don't know won't hurt them.

Not yet, at any rate.