Humidity has been around 80-90% recently, and the temperature that day was probably no higher than 30.

I don't know whether you can afford it, but it may help to buy a dehumidifier to lower the humidity in & near your kitchen. That should make it harder for mould to grow successfully.

A new one costs £100-200 here (which Google's currency converter says is about 30k-60k HUF), but they should last for 3-10 years, so the cost is amortized over quite a long time. The only maintenance they should need is being emptied daily (maybe twice a day in a very humid environment), which only takes a couple of minutes.

Edit: of course, before you buy one, it's probably a good idea to borrow one from a friend or hire one so you can test it for a few weeks and see if there's an improvement first.