Effective service tax for outdoor catering limited to tax on part of gross charges, subject to invoicing and credit conditions. Service tax on outdoor catering is partially exempted by permitting tax liability to be calculated only on a portion of the gross amount charged, provided the invoice indicates charges inclusive of food supply; no Cenvat credit has been taken on inputs or capital goods; and the caterer has not availed benefit under the earlier notification. 'Food' is defined as a substantial and satisfying meal.