Answer: A control density dependent limiting factor.
A food processing is a process of increasing the shelf life of preventing the growth of bacteria and improving it's taste. A density dependent limiting factor is the one which affects the size and growth of the population depending upon the density of the population. Food is a density dependent limiting factor as it effects and availability are dependent upon the density of the population.
Food processing is advantageous in a sense as it maintains the quality of food hence, is a control over density dependent limiting factor.