Rates of the meals are based on factors like ingredient prices, labor charges, administrative charges, and profit margins. Normally, future increases in the prices of the ingredients are considered while fixing the rates. However, many times it so happens that the increase in the prices is very high, and the contractor is not able to absorb the same. This happens mainly in two areas:
a) Labor charges: Due to revisions in the minimum wages, the contractor has to bear the extra burden regarding PF and ESI contributions. Normally, all companies have systems to offset this rise by including the potential rise in the minimum wages in the rates.
b) Increase in the rates of cooking oil: The rates of cooking oil are highly fluctuating. Companies typically revise the rates if the price of oil crosses certain values. It's essential to understand that contractors do business to earn a profit, and if they are unable to generate profit, they may try to manipulate either by adjusting payments to workers or making changes in the quality of foods. It is my suggestion that you always fix the rates considering the expected rise in minimum wages and oil prices.