How many pounds must a sand bag weigh to test if a safety net can absorb the proper amount of force?

You did not show us the image of the burger, but i shall try to answer as best i can.  when purchasing food, always consider the ingredients as well as the person who prepared it. consider if they were hygienic people or not, in case the burger was infected with bacteria. no mortal should place an infected burger into their mouth.   

The answer is sensory neruon