For your original question: you typically cannot sell cooked food from your home kitchen in the United States. This Californian law reflects a large relaxation from the status quo.

There are "cottage" food laws which allow the sale of baked goods, jams and jellies. But foods that require refrigeration after preparation are typically not covered.

https://ij.org/issues/economic-liberty/homemade-food-seller/ has a fairly good state-by-state summary. You'll note that even in the "dark green low regulation states", only Wyoming and North Dakota have no restrictions; Utah, Montana, and Oklahoma restrict meat.

edit: You seem to be in the UK. The regulatory environment is a lot more lax there. Inspections and approvals seem still to be required [1], but that's different from the general prohibitions found in the US.

[1] https://www.gov.uk/food-premises-approval

Well, the problem is... food safety is a medical nightmare when safety practices aren't observed.

As a personal note, the sickest I have ever been in my life was from food poisoning. The details are horrific, but imagine 3 days of violent diarrhea while at the same time throwing up. I couldn't even hold down water. My arms looked like, its hard to explain... the skin was draped over them. You could see every sinue of the musculature like I was a body builder, except I was a fat 30 year old. I went to the hospital and took 4 liters of saline.

All I did to earn that punishment was eat a few slices of pizza that had been left out too long.

If you please, the saga of the "pink sauce", which is the exemplar of why food safety has to be regulated:

https://youtu.be/fa-qq4lK0NY?t=2790

I like to imagine that there are some health inspection checks in place when I order food online.

It is highly regulated everywhere in the US, but a lot of people in every state are working to improve the regulations and reduce the burden while making sure that food safety is a priority.

Success leads to more success. Be happy that California has made an improvement; it will be used to make things better in your state next.

In the UK, if you sell food made at home, you are subject to all manner of laws that you must comply with — to not follow such laws does, to operate outside of such laws, means that one's business is not legal, and thus illegal, no?

I'm pretty sure that this is the same in lots of countries.

— Related story, cos it's arguably more interesting than the argument here... My friend makes and sells a Chilli Jam, from homegrown chillies. Just once a year. He used to make his jam batches at home. But ran afoul of the various rules and regulations that make up UK food law. So now he simply gets himself some time in the kitchen of an already established restaurant to make his batches, because it's much easier than setting up one's own home for such a business — particularly for a single annual batch.

Edit: sure, one could easily argue that the UK is an over-regulated hellhole, I guess /shrug

I imagine the context for something like was they put in place blanket regulations for food safety; kitchen must have a drain to make it easier to clean, water must be hot enough to sanitize, must be inspected periodically, food must be tested and labeled before sale. It's often later they come in and make exceptions for low-volume, low-risk situations. I've noticed "cottage food laws" have popped up over the past decade (California passed some back in 2012).

A similar example is home brewing beer. Obviously, Prohibition happened in the 20s and 30s and it was heavily regulated afterward. It wasn't until the 70s when it was legal to home brew beer. You still hear craft brewers complain about the laws around distribution for smaller guys.