With their multi-billion pound colonisation of town centres and suburbs, supermarkets make easy targets for campaigners.
While it's generally true that the big grocery chains push out local traders, beat down suppliers and homogenise food, they are highly responsive to the concerns of their shoppers, and about what those shoppers learn about them in newspapers or on television.
In the past few years British-owned chains such as Tesco, Sainsbury's and Marks & Spencer have stopped selling endangered fish, handed out fewer plastic bags and cut salt, sugar and trans-fats in products, often very substantially.
Aside from their natural public-spiritedness, they do this partly because they cannot hide what goes into their processed products; labels tell their own peculiarly-worded tale of intensive processes and E numbers. And partly because stores feel the heat from campaigners, politicians and customers, who manifest their views occasionally in direct communications and more frequently and indirectly in market research.
Admittedly, the grocers perform less well when the heat is off; witness their failure for years to tackle the important but unpopular issue of forest-wrecking palm oil. Nonetheless, generally, grocery multiples act to protect their reputations and customer loyalty, thereby driving up standards.
A better place to look for dodgy practices affecting consumers' health and finances, or environment or animal welfare, is eating out. Far from being the occasional treat it was 20 years ago, cafe and restaurant meals are now commonplace and four in every 10 meals are consumed out of the home: a croissant on the go; a lunchtime sandwich; a pub or restaurant meal. Unlike the rapacious supermarkets, firms providing this food are more likely to be locally owned and their "fresh" food does not carry labels.
While many meals eaten outside the home are lovely in every way, the sector has more secrets than the brightly-lit store aisles. First, its food is laden in fat and sugar. While it's hardly a surprise that restaurant dinners are high in cream, calories can be sky high.
A survey in 2007 found that one in three pub and restaurant meals contained 1,500 calories – three-quarters of a woman's recommended allowance of 2,000.
A Pizza Hut "cheesy bites" Hawaiian pizza has a whopping 2,538 calories.
Another area is salt. Excess consumption of salt, not at the table, but hidden in cheap food, sends 15,000 Britons a year to early deaths with heart disease.
A survey by the anti-salt campaign Cash last year found some three-course pub meals could exceed the recommended six grams a day. At Vintage Inns, for instance, anyone having the tomato and basil soup, hunter's chicken and sticky toffee pudding would knock back 8.28g.
Meat. The Independent disclosed last year how restaurants and fast food outlets are selling chicken surreptitiously bound with water by beef protein. Typically produced in Holland, this type of chicken could be served to you in an Indian or Chinese restaurant, probably without the owners' knowledge.
Hygiene. While one in 1,000 major supermarket stores scored a dangerously worryingly zero stars in environmental health inspections last year, the total for food outlets in general – including restaurants, pubs and cafes – is one in 20. Conditions at these places are likely to be disgusting; you can check hygiene scores online for most areas of England.
Although many cafes now stock Fairtrade coffee or tea, the proportion of products with ethical stamps is far lower than in stores. So while almost half of eggs sold in shops are free-range, that falls to one in five in catering and processed food.
The chicken or pork you eat in the shop sandwich or takeaway meal is highly likely to have had a short, cramped and boring life.
Of course, none of this means that you shouldn't enjoy a lunchtime sandwich, a kebab or a blow-out meal, but it's worth bearing in mind that you are eating food whose ingredients and provenance are unlabelled.
Heroes & Villains
Hero: British beekeepers
The disappearance of bees from the countryside over the past three winters has been something of abstract interest to city-dwellers, until now. The British Beekeepers' Association is inviting members of the public who cannot keep bees to sponsor a hive. The money raised will fund research into bee health and training beekeepers. "We cannot take it for granted that the bees will always be buzzing around," are the honeyed words from the chef Raymond Blanc. For £29.50 you receive a jar of honey, a fridge magnet, a wooden honey dipper, postcards, factsheets, a certificate and – it doesn't mention this but I'm sure it's included – a warm glow.
Villain: Car dealers
Put on a seatbelt and brace yourself for a shock: some second-hand car dealers are rogues. A report by the Office of Fair Trading into the £24bn-a-year trade found the vast majority of faults on used cars emerged in the first three months, suggesting "many second-hand cars sold may not be of satisfactory quality". Drivers were spending £425 each, or £85m a year, fixing faults that should have been repaired by dealers. Arthur Daley is alive and well.