Tex. Tax Code § 151.3141

(a) Items purchased in whole or in part with food coupons issued under the food stamp program from a business approved for participation in the food stamp program are exempted from the taxes imposed by this chapter. The exemption applies only to items permitted by law to be purchased with food coupons under the food stamp program. If two or more items are purchased together and paid for with a combination of food stamps and other means of payment, for purposes of this section the food stamps are applied first to the purchase of items that would be taxable under this chapter in the absence of the exemption provided by this section.

(b) For purposes of this section, "food stamp program" means the program operated under 7 U.S.C. Chapter 51.

(c) This section and Subsection (e) of Section 151.412 of this code expire on the first day of the next calendar quarter after the comptroller certifies and publishes in the Texas Register notice of the certification that federal law no longer prohibits a state from participating in the food stamp program if the secretary of the United States Department of Agriculture determines that state or local sales taxes are collected on items purchased with food coupons issued under the food stamp program or that for any other reason the exemption provided by this section is no longer required for this state to participate in the food stamp program. The comptroller shall make a certification under this subsection if information sufficient to make the determination becomes known to the comptroller.