I live in Milan, Italy in the city center. I started seeing this insect in August after a long vacation. In this periods the temperature inside the house went up to 36°C (temperatures here range from -1°C to +35°C in average).
I find it mostly in my kitchen in particular in a cabinet where i store food.
The size is about 3mm in length and less than 1mm in width.
What is its name so I can research more about it (i.e., does it pose any risk to my health or to my belongings in the house?)?
I have tried to use a common bug spray to get rid of it (i.e., emptied the cupboard, got rid of food that was not sealed and sprayed the cabinet profusely). It was unsuccessful as after 10-15 days it came back.
Is there a more appropriate bug spray to get rid of this insect?
Should I be looking for nests or eggs?
EDIT
Additional close-up pictures with a cheap microscope.