Undigested bits of mushrooms and tomatoes from Christine Morton’s last meal — a celebratory birthday dinner she had with her husband — were still in her stomach when the medical examiner performed his autopsy in 1986.

Those remnants, the prosecutor told the jury during Michael Morton’s trial, “scientifically proved” that Morton had beaten his wife to death.

Twenty-five years later, DNA science revealed that someone else had actually killed Christine Morton and that her husband’s murder conviction and more than two decades in prison were a tragic mistake. His exoneration based on DNA evidence is the 45th in Texas.

Before he dismissed the wrongful murder charges against Morton last week, Judge Sid Harle recounted the faults the case exposed in the Texas justice system. Among them: the use of so-called junk science in the courtroom.

“The courts and the sitting judges need to be ever mindful about their role as gatekeeper in regard to the admission of science,” Harle said. “Your case illustrates the best and the worst of what can happen.”

Despite scientific advancements like DNA testing, the use of unreliable scientific techniques in the criminal justice system persists. While some judges say they work to ensure only reliable scientific evidence is presented to juries, criminal justice advocates say that more must be done to root out an array of pseudoscientific practices that can have life-or-death consequences.

“What passes for science in courtrooms is not always, in fact, science,” said Kathryn Kase, interim executive director of the Texas Defender Service, which represents death row inmates.

In recent weeks, the Texas Court of Criminal Appeals has agreed to review cases that indicate it may also see a need to address the types of evidence that meet scientific standards.

In November, the state’s highest criminal court agreed to review the case of Megan Winfrey, who is serving a life sentence for murder. She was convicted largely on the testimony of a sheriff’s deputy who said his bloodhounds “alerted” to her scent on the murder victim’s clothing. The court has previously ruled that dog-scent evidence, used to convict Winfrey’s father for the same murder, was insufficient without corroborating evidence. The court acquitted her father on appeal.

This month, the court also agreed to review the cases of two men awaiting execution. Both men, convicted of murder, were sentenced to death after a psychologist who was an expert witness in several death penalty cases told jurors that they were mentally competent to face execution.

Lawyers for the men — Steven Butler and John Matamoros — argue they are mentally handicapped and therefore ineligible for the death penalty. In April, the Texas State Board of Examiners of Psychologists reprimanded the psychologist, Dr. George Denkowski, and he agreed to never again conduct evaluations in criminal cases.

Though Kase said the court’s willingness to review the cases is a hopeful sign, she and other criminal justice advocates said other relatively simple changes could help prevent the use of such evidence.

Judges, who ultimately decide what is allowed in court, should approve adequate money for indigent defendants to hire experts to refute scientific experts whom prosecutors present at trial, she said. It can cost thousands of dollars to hire experts, and Patrick McCann, a Houston defense lawyer, said judges worry that voters would not take kindly to such expenses.

“They act as if funding each defendant’s efforts to have a fair trial comes out of their own children’s pockets somehow,” McCann said.

For three legislative sessions, Jeff Blackburn, chief counsel at the Innocence Project of Texas, has pushed to ban evidence that does not conform to national scientific standards. He will try again in 2013 when lawmakers reconvene.

“These are problems that can be fairly easily solved,” he said.

Sen. Rodney Ellis, D-Houston, said another key solution already exists: the Texas Forensic Science Commission. For more than two years, the commission was bogged down in a national political controversy over its investigation of arson science used to convict and execute Cameron Todd Willingham for a 1991 fire that killed his three daughters. That issue was resolved this year with a plan to review past arson cases to see whether similar faulty evidence led to questionable convictions. Now, Ellis said, he hopes the commission will address other questions of courtroom science.

“To have a justice system we can have faith convicts the guilty and protects the innocent, we need scientific evidence that’s based on real science,” Ellis said, “not some guy saying he has magic dogs that can solve crimes.”