In the poor student or youth worker days it was popular to have never ending soup; a large pot on the stove that was topped up with new and leftover ingredients when available.
Normally the pot was stored in the fridge overnight.
Food items added were sometimes plate leftovers from fellow flat (share house) mates, who would in turn be eating the soup, too.
Most days other ingredients would be fresh(ish) vegetables, beans, grains, and fresh meat products sourced from the local butcher as money allowed.
Brussels sprouts where banned, and so were strong spices (you added those to your bowl before serving).
Also, for irony, a large (cleaned) stone is always left in the pot.
Fresh bread was sometimes baked in the oven while cracked bones were browning, but the oven was often an electrical and environmental death trap.
The pot kept going till the summer holidays, and no one got food poisoning in my time, or from any student stories I have ever heard.
This sort of activity is recorded in history as being a popular resource-saving idea.
Are there any real food safety implications with this method of cooking? And have any actual studies of this technique ever been published?
I still recommend this money-saving idea to current students, not keen on bad practices being continued though.