You will receive the subsidies via your paycheck in the following month (e.g. for receipts / tickets submitted in May you will receive the subsidies with the paycheck of June).
Taxes and social security are withheld from your gross salary by your employer and you get your net salary transferred to your account. Your net salary increases through billyard and the use of payroll tax and social security free allowances. So ...
Yes, food subsidies may also be granted to employees who already receive the maximum limit of €450 as remuneration. The only requirement is that flat value taxation must take place and the amount may not be taxed individually.
All information of the settlement of subsidies as a salary subsidy can be found on page Abrechnung von steuerbegünstigten Zuschüssen. The linked page is only in German available