Is it permissible to pay a cash allowance in lieu of meals provided at work, if the contract with a government entity stipulates the disbursement of meal expenses, and the contractor is the one who pays for them?

If the employment contract includes the worker's right to receive a meal allowance for his working days at the site, and the contractor pays the meal allowance on behalf of the employer or by agreement with them, then there is no harm in taking the meal allowance from the contractor.