cocaine granola bar
The bag of cocaine that Cynthia Rodriguez found inside the packaging of her granola barCynthia Rodriguez

A Texan grandmother got slightly more when she bargained for when she opened her oats and honey granola bar - a gram of high quality cocaine inside a baggie covered in dollar signs.

Cynthia Rodriquez, 60, initially thought her strange discovery of a small bag of powder meant she had won a prize, but the bemused Nature Valley worker who answered her phone query suggested she phone the police.

She reported the incident to the San Antonio Police Department on 18 March, which tested the suspicious power for heroin. When the tests came up negative, they tested for cocaine.

"He tried for cocaine and they both looked at each other and he goes 'oh my goodness, its high quality cocaine,'" Rodriguez said.

Detectives are investigating how the powder got inside the granola bar. In the meantime, the drugs, wrapper and bar have been bagged and kept as evidence.

"We're not sure if this was something added on purpose or if it was something that may have fallen out of someone's pocket on the assembly line," Sgt. Javier Salazar told KENS 5.

"It's a somewhat disturbing case...You think of a child getting a hold of a package that's got interesting symbols on it, dollar signs in this case, and ingesting something like cocaine that could have a possibly dangerous effect, maybe even deadly on a child."

The company that owns Nature Valley, General Mills, said they were "confident" the drug was not packed with the bar at their facility.

Their spokesperson said that it would be "difficult" for someone to drop drugs inside a granola bar wrapper as the bars move quickly along factory assembly lines.

This has not necessarily reassured Rodriguez, who dreads to think what could have happened if one of her 11 grandchildren had made the discovery.

"What if they thought it was sugar?" she told KENS 5.