Applicability of tax on meal vouchers

I work for a Public Sector Company which provide Sodexo Meal coupons to all the employees on a working day basis.  The company provides Meal coupons on a monthly basis for the number of days worked in a month.  The coupons vary from Rs.75 to Rs.200 depending on the category of officers.

Now the company has informed that meal coupons beyond value of  Rs.50 would attract Income tax and would be treated as Perks.

Can anyone tell me if this is ok?  Is there any ceiling fixed by the Authorities for deducting tax on meal vouchers?

Thanks

Srinivasan