You left out a bit of the system – neighbours would provide table scraps for one another’s pigs, that way even those who didn’t keep a pig of their own could join in. Nina Bawden drew on her own family history to fictionalise this in The Peppermint Pig
Plus there are all the things that when you stop to think about it are actually archaic holdovers from the days when refrigeration (or even reliable canning) wasn’t available.
For starters, the cliche’ that mice love cheese. Actually they love a lot of other things better, but a cheese was something that might be kept in a pantry long enough for the mice to get at. Cheese kept because the outside would form a dried out rind protecting the interior, and to an extent a cheese is rotten, just with the right kind of mold.
A “smoked” ham (or side of beef, leg of lamb, sausage, etc.). You stick a piece of meat in a smokehouse. The smoke keeps flies from spawning maggots on the meat until the outside is too dry. The elevated temperature in the smokehouse raises the temperature of the meat until it is sterilized, and the smoked outside serves as a barrier to bacteria. You hang it from the ceiling because most attics are unheated in the winter. And “aged” meat was meat that had been around long enough to start to get soft.
Jelly and jam: You boil down a fruit mash until the sugar concentration is too high for microbes to survive in it. That’s how they got the name “preserves”.
Ditto pickling (concentrated vinegar), ditto salting (concentrated brine).
Why did sailors get a ration of grog every day? Partially of course because they were hardened alcoholics who would go into DT’s if they didn’t get booze. But also because distilled spirits would keep almost indefinitely, and their grog ration was an important part of their daily calorie intake. “Hardtack” was rock-hard dried biscuit or crackers because a sailing ship could seldom carry enough fuel and water to bake fresh bread.
The “root cellar” was where you kept vegetables in the relative coolness and darkness of a cellar to prolong their life.
I don’t have it handy but something like the Oxford Companion to Food should have information about this topic.
You’ll probably be able to get it at your local library.
You local university library probably has diaries from local settlers in it (presuming you live in the US), especially if the town has ever had a centennial, bicentennial, whatever celebration.
There could be a professor there who is knowledgeable in this area of history. I talked to a professor from the university where I grew up for a science project, and he got a kick out of a seventh grader who was interested enough in albumen to conduct a phone interview with someone she’d never met. Most of the professors I’ve met are more than willing to share their knowledge. YMMV
Your son might want to mention that the daily life of medieval ladies in charge of households were anything but genteel. One of their duties, if the household was small enough that they were involved in food preparation, was to pick the maggots out of the meat before cooking it. Spices were highly prized not only because they tasted good, but because they masked the flavor of rotting food. He could also mention Napoleon’s role in bringing about canning.
The Land Remembers by Ben Logan has a humorous account of finding drowned mice in milk cans at a dairy. Milk cans were used to hold milk in bulk before large refrigerated holding tanks and milk trucks were used. (Refrigeration revolutionized the dairy industry, like every other perishable food.) The book might have some other mention of pre-refrigeration times, but it’s been a long time since I’ve read it.
I’ve heard quite a few reputable people state that this is in fact a myth.
I think one of the biggest changes in our lives, the one we mostly take for granted, is the advent of refrigerated trucks in combination with roads, air cargo, etc, which allows us to eat anything we want any time of the year. Can you really imagine going through the winter without real greens? Only root vegetables? Eating the saddest, wizened apple from the bin with the sorrow that comes from knowing it’s the last until next year? Imagine how good strawberries would be if they were the first ones you’d had since that time last year!
I know it had a great deal to do with changes in the commercial fishing industry - you could go out further, on a long trip, catch a lot and put it on ice. Didn’t somebody invent an ice maker or something for fishing ships? No idea when that was, but I’m sure it’d be an interesting line of research.
Anyway, refrigerated transportation would be another great place to look in terms of what really changes people’s lives.
This is very important - get him to look into the history of livestock trading, markets, etc. The only reason people would eat bad meat was because they were too poor to buy any, or because there was a general food shortage. Also, as hinted somewhere else, the development of railways made more foods easily available to more people - even without ice, fish could be transported a long way inland in a matter of hours, something never possible before.