By F.D. Flam / Bloomberg Opinion

Last month, a bungled health warning over black plastic spatulas didn’t help faltering trust in science.

First, researchers warned us to throw away the ubiquitous utensils because the recycling process might have incorporated toxic contaminants beyond the Environmental Protection Agency’s safety limits. Then someone pointed out the researchers had made a big math error. The black plastic warning turned out to have been based on incorrect information. Contaminant levels were actually more than 10 times lower than EPA limits.

It wouldn’t surprise me if Americans remained wary of black plastic utensils. Alarming health news, especially when it comes from prestigious universities or other trusted sources, has a way of lodging in people’s minds. Corrective information, such as reports pointing out the math fumble in the black spatula study, has less shock value and tends to get lost in the torrent of news around the initial scare. And scientists themselves are often unwilling to pull back completely from health alarms that they had a hand in initiating, leaving worries about certain substances or practices to linger in the public consciousness long after doubts over their original findings emerged.

The great proliferation of black plastic spatulas itself was spawned by a spate of health scares of varying credibility. Experts had warned that it was dangerous to use a metal spatula because it could scratch nonstick cookware, allowing plastic and “forever chemicals” into food. Before that, we bought the chemically coated pans because of a scare over fat, which for centuries had kept food from sticking to cookware.

Scientists inevitably are going to make mistakes, but in this case and others like it, they stuck by their conclusion that the products they studied had high risk potential even as they corrected their math.

Sometimes researchers might gloss over problems with their findings as long as they feel that the overall message will lead to good outcomes for society. And it probably isn’t the end of the world to lose all those plastic spatulas. But often there are unintended consequences.

That was the case decades ago, when experts began warning about cholesterol and heart health, insisting that all fats were harmful. Now, after many years, public health officials have conceded that fat isn’t always bad. They’ve sheepishly put eggs back on the list of healthy foods after telling Americans for years that they would clog our arteries and kill us.

I’ll admit I tossed out a black plastic spatula last month, and I don’t regret it. I had no reason to own it, since I’d jettisoned my last nonstick pans years ago. And there’s a grossness factor in how the alleged contaminants got there: Flame retardant-laced plastic from electronic waste can sneak into the material being recycled into food containers and cookware.

Former industry chemist Mark Jones — now an independent consultant — had alerted me to a very similar scare story last year, when researchers made the extraordinary claim that each week we swallow enough plastic to make up a typical credit card. The claim made international headlines, and was touted by politicians, environmental groups and the United Nations. But when other scientists tried to replicate it, they found the estimate of our weekly plastic ingestion was too high by about a factor of a million.

What bothered Jones wasn’t that scientists make mistakes but that the mistake kept getting cited in yet more scientific papers and media reports. In a similar way, the authors of the spatula paper claimed their math error didn’t affect their conclusion.

The decades-long egg scare started when government scientists sought to simplify public health messages in the quest to fight heart disease, said Gary Taubes, a journalist who has looked deep into the history of food science for his myth-busting books on diet and disease.

In the 1960s, scientists learned that people with high levels of cholesterol in their blood bore a higher heart attack risk. They had recognized way back in the 1930s that humans make cholesterol in our livers, and eating cholesterol-containing foods didn’t have much effect on blood cholesterol. The foods that raised blood cholesterol were those that contained something else — saturated fat — mostly found in red meat and full-fat dairy products. Eggs are high in cholesterol but not in saturated fat, and though it was known they were unlikely to cause harm, Taubes said health authorities at the time deemed it simpler to lump them in with meat and cheese.

(Since then, newer studies show dairy fat may also have been wrongly put on the forbidden list, and the trans fats used in margarine and some junk food were so toxic they were finally banned.)

Once the most health-conscious people — those likely to exercise and avoid smoking — start giving up eggs, Taubes noted, it was impossible to draw any conclusions about eggs by comparing egg eaters to egg shunners. And telling people to avoid eggs led some to switch to sugary, starchy alternatives: pancakes, cereal, pastries and the like. That might have contributed to skyrocketing levels of diabetes and obesity. Similarly, telling people to throw out those plastic spatulas could have unintended consequences if consumers are now using metal ones and scratching up their nonstick pans.

The other unintended consequence of fudging the truth is the erosion of the public’s faith in expertise, a problem that is contributing to people putting their children at risk by skipping childhood vaccines. The simplest way to sustain public trust is full-on honesty, even when the messages are complicated.

F.D. Flam is a Bloomberg Opinion columnist covering science. She is host of the “Follow the Science” podcast.