How do you tell/deduce if someone is a chef
Especially the hands are a good place for deductions if someone is a chef. For example chefs tend to have very clean and well kept hands, with short nails, no nail polish and mostly no rings or other decorations that could be a hiding and breeding place for bacteria and dirt, which could then be transferred to the food, which would be a significant risk for food safety. Hair and beard are often also kept short or in a ponytail, otherwise they have to wear hairnets. Also their habits like repeated handwashing and hygiene habits could represent their profession, but alternatively could also be someone in healthcare.
The most telling would be that they themselves could smell like food if they are spending most of their time in the kitchen, surrounded with the steam of the cooking and the olfactory molecules of the food which then cling to the skin and hair. You can also tell what exactly they are mainly preparing if you can determine the smell. Often covered in grease if they work with the fryer, smelling smokey if they work the grill, and especially onions and garlic is a smell hard to get rid of especially on their hands where they directly handled and touched the food. A pâtisserie chef will smell different than someone who fries onions and meat all day. They can also smell like specific spices that could indicate certain foods, for example if they cook in an indian restaurant. Some foods can also stain the hands, e.g. curcuma stains hands a bright yellow.
Burns or cuts on their hands from mistakes while cooking, or general thickened skin because repeated exposure to heat.
Another very telling indicator is a knife callus on the lower part of their dominant hand’s pointer finger where they control the knife, most chefs who have done the job for a significant amount of time have this callus.
How they handle certain utensils like knives could also be a clue, whether they are able to cut professionally or like an amateur, how they hold forks and spoons. Another indicator for working in gastronomy in general is if people can carry several glasses or plates at once, how well they can balance without dropping anything.
And of course the easiest would be if you see them in their chef uniform or work clothes, then you don't need to be a genius to deduce their occupation.