Is the Per Diem I received from my employer taxable?

I received a per diem from my employer while traveling outside of the country. The per diem was $50/day. The employer does not require employees to submit receipts to substantiate expenses. However, the amount is below the per diem limits. Is this amount considered taxable? I received a 1099 from my employer for this. I do have receipts that substantiate food expenses incurred while traveling. Can I deduct the expenses incurred from the income received from my per diem??