These people are likely to wash their hands afterwards then think nothing of answering their smartphones when preparing food. I'm surprised that health officials don't make a much bigger deal of the fact.
Anyway, if you wish to inflame your cellphone hygiene nightmare, look no further and behold: https://www.nejm.org/doi/full/10.1056/NEJM199209033271004
I say that not as an obsessive hand-washer or an anti-germ-freak like Howard Hughes but because it's just commonsense. It also comes from being taught as a child both by my parents and at school to wash my hands before eating food and to be hygienic around food preparation such as washing fruit before eating it. That early training has meant that if say I were to sit at the dinner table without washing my hands I'd have a feeling of being dirty and have the urge to wash them.
I'm not alone, many others have similar a experience for the same reason. That said, I suspect the percentage ought to be much higher than it actually is (simple observation tells me that).
Again, I'm careful but not obsessive about hygiene and I like most others have occasional minor lapses such as eating an apple or picking strawberries from a punnet without first washing them. Nevertheless, I'm aware of the fact and feel somewhat guilty for not having done so.
Similarly, I'm always aware of the many almost futile practices people adopt in the name of hygiene. For example, the commonplace and token-like habit of shop assistants with disposable gloves on preparing say bread rolls and then handling money especially so notes (which are particularly dirty and germ-laden) and not changing to a new pair before the next customer (the same can be said about them handling their smartphones at the same time).
Long gone are coins with high silver content that were in part self-cleansing (Ag has strong antimicrobial properties).
BTW, if one takes the effort to wipe one's phone with a tissue with a few drops of ethanol (or rubbing alcohol—isopropanol for those in the US) on it then it serves a dual purpose, greasy fingerprints are removed and one's screen is clean—and the alcohol kills most of the microbes.
It's interesting to note I purchased a Vietnamese-style bread roll for lunch today (presumably the owners were originally from Vietnam), and noticed the woman serving me had only one protective glove on—on her right hand. What was particularly noticeable was that she prepared the roll with her gloved hand and put it in a new paper bag without her other glove-less hand touching anything (tongs acted as her second set of fingers). At the cash-register I handed her a $50 note and rather clumsily with her left hand she deposited my note and returned notes and coins as change without using her gloved hand at all. Clearly, she was very conscious of hygiene. Why her and rarely others? Incidentally it was a small family-owned shop so the woman wasn't just acting out the hygiene requirements of say large chains like McDonald's.
Moreover, as COVID has diminished I've noticed very few now wear masks but the vast percentage that still do are Asians (BTW, I'm in Australia which is a mixture of every nationality).
Take from that what you will.
If say you've the highly contagious and all-to-common Noro virus, and even if you've washed your hands thoroughly and then touch your contaminated smartphone you'll go on to contaminate almost every surface you touch, food and everything else.
Why don't people still understand this given that it's had such huge airing in recent years (as it's such a significant problem on cruise ships)?
That people still don't is the reason why medical and health authorities should be much more proactive in this area.