That's just the problem though ItsAllGoingtoBeFine. One of the first things any therapist dealing with a woman with postnatal depression or anxiety will talk about is how anxiety is maintained by the perceived probability/awfulness of a threat - so this type of anxiety is directly maintained by the same sorts of discussions we have about infant health.
It really doesn't take an awful lot for guidance to lead to obsessions and compulsions in women. I should know. I was one of them. In my case I had a particular obsession about water temperature and I could easily spend up to an hour checking and rechecking the temperature of my baby's bath and even more checking and rechecking the temperature of the baby's room. Hours. Hours and hours and hours.
There is published evidence about scalding of babies and of higher room temperatures leading to death - these are definitely actual real risks out there in the world. However, they don't really warrant the level of vigilance that I and the thousands of other women who are suffering postnatal mental illness apply to them.
Unfortunately, when it comes to babies and published research, if you rigorously apply the formula
Consequence = death
Probability = low
and you factor in the need for a caretaker to be "responsible enough" to "never take the chance", it really doesn't take an awful lot for clinical behaviours to take root. I had no history of this sort of thing, many women don't. Our culture is incredibly risk averse to the point that it is easy to believe based on what you read that if you only do everything "right" that you will eliminate risks. You won't. Ever. If it's not infant formula it might be roller blinds or scalds or accidents on the stairs/with the windows/in the bath/in the car. It's easy to pretend that the tendency to tip over into obsessing vs worrying is about the individual but when you see how we talk about these very small risks, it's clear to me that the verbal community we live in actually initiates and maintains a lot of unhelpful psychological behaviour.
Does that mean that you shouldn't take sensible precautions? Of course not. However, it's best to just be realistic about what you are going to do (if you know you are going to find it hard to follow the guidelines as you are already on edge and this sort of thing might really get to you in your deprived state, use the bloody cartons) and also to remember that it is just guidance and there will be people who are actually doing terribly dangerous things whose babies will be safe and people doing terribly safe things whose babies may sadly suffer harm.
I just hate, hate, hate when I see people talk about "high risk" of low probability outcomes because frankly, there's enough pressure out there in terms of becoming a parent in a world with limited support systems for many women. Salmonella is awful. I'd hate my baby to get it... but I have learned with the benefit of time and therapy that slavishly following guidance is no guarantee of safety and a sensible, balanced approached to anxiety is to find out what to do and just get on with it avoiding all Dr. Google/Mumsnet scare stories along the way.