I was very impressed by the companies inat "FOOMA" which is held in Japan to promote the food industry.

If "FOOMA" is an event and not a place then it should be "at" instead of "in".

There were quite many companies'y booths, and I could see various machines.

1. "Quite many" doesn't really work. You can either say "quite a few"/"quite a lot" or just "many".
2. Technically "companies' booths" (plural) would be correct but it sounds quite strange.

I was very impressed that these machines have made ourmake the foods we eat every day.

Or "...make our food every day".

Has anything impressed you recently?

Titles are usually written in title case, which has special capitalization rules.

I was very impressed by companies in "FOOMA," which is held in Japan to promote the food industry.

Also, it would be more normal to either:

1. write the full name of the event without the abbreviation

OR

2. explain what the event is

For example, you could say

I was very impressed by companies in "FOOMA," a large food processing event, which is held in Japan to promote the food industry.

There were quitevery many companies'y booths, and I could see various machines.

"very many" is more normal, or you could also say "quite a lot of"

Also, I changed it to "company booths" for concision. If there are 5 booths, for example, from different companies, then booth 1 is a company booth, booth 2 is a company booth, and so on. So each booth is a company booth. Since there are multiple, it would be "booths." And the word "company" serves as an adjective to describe what kind of booths they are.

As another example, in a skyscraper, we would say that there are "business offices" and not "businesses´ office."

I was very impressed these machines have made ourthe foods we eat every day.

It is more normal to see "the" food if it is being talked about generally.