It's pretty much impossible to avoid germs without living in a bubble. Door handles, ATM keyboards, money, shopping trolley handles etc must all be filthy. Having said that, I once heard someone say she would never use a library, because you didn't know where the books had been
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But back to the point of the thread, I put everything in the washing machine together, nearly all on a 40 cotton wash, except some of my delicates, which go on a hand wash programme. I've never thought about cross contamination. The point of the machine is to clean things and a fair amount of rinsing goes on. If there is anything left, it will be massively diluted to almost homeopathic levels.
DP and I are never ill and we generally share our (thankfully quite big) bed with various cats (we have 4 of our own and also foster - we have 6 kittens as well at the moment - a fair few of these like to sleep on the bed. There is a cartoon that goes round the internet that basically says, if you have a cat, it's arsehole has touched your surfaces and furnishings. For this reason, I tend to wipe up before cooking, not afterwards.
I routinely put the washing machine drawer, oven door glass, cat food bowls, food waste caddy, kitchen bin and even once a cat litter tray in the dishwasher, but I did do a cleaning out wash after this and that was a one off before carrying out some urinary analysis on a sick cat - he needed to pee on clean litter so wanted to avoid anything in the tray or from other cats.