Months after news first surfaced of contaminated peanut butter, a national nut emergency continues. After issuing its first-ever blanket warning about a food that had so far caused exactly zero illnesses – pistachios – the Food and Drug Administration put the food industry “on notice” as to its plans to make some major changes to the food-safety system.

Plans to improve surveillance of food-borne illnesses – as well as our preparedness for swine flu and other non-food-borne epidemics – would normally come as a relief. We hope our government can protect us from genuine threats to public safety. So we applaud 911 operators, traffic lights, and poison-control hotlines.

But sometimes, a public-health movement goes too far. I’m reminded of a poster on display at an obesity conference a few years ago: “Public health,” it read, “is everybody’s business.”

It turns out pistachios aren’t the only food fear inspiring sweeping government intervention.

To New York officials, who simply won’t mind their own business, salt and cooking oil might as well be cyanide. New York City “health czar” Thomas Frieden has committed himself to forcibly removing almost half the salt from New Yorkers’ diets. And Gov. David Paterson has announced that his new War on Obesity will begin with a statewide expansion of New York City’s trans-fats ban. If Paterson succeeds, margarine and shortening will become contraband almost everywhere food is sold in the Empire State.

Anyone familiar with our country’s track record on internal “wars” (think drugs and poverty) should be skeptical of anti-fat crusades. Adding a little extra salt to your french fries, or cooking them in an oil that some people find tastier, isn’t worthy of government intervention.

Unless we’re talking about the hazards of a salmonella-spiked nut mix, consumers know that some food choices carry more incremental health risks than others. It doesn’t take a registered dietitian to point out the difference between a salad and a triple bacon cheeseburger.

And remember: There’s no such thing as “secondhand fat.”

What there is, science shows, is a predictable formula for basic health and longevity: dietary moderation and regular exercise. But there’s no expert consensus about the effects of government measures such as soda taxes and salt bans.

Show me a study touting the health benefits of a low-sodium diet, and I’ll show you another concluding that it could actually increase the risk of cardiovascular disease and other health problems. For every Ph.D., it seems, there’s an equal and opposite Ph.D.

And quick-fix recipe overhauls inevitably bring unforeseen consequences. What did the two-decade-long campaign against saturated fats produce? Responding to mounting pressure from government and food activists, restaurants switched to trans fats.

Similarly, as New York Times science columnist John Tierney has pointed out, banishing trans fats or salt will open the door to substitutes that may or may not be more healthful.

It is easy to point to pressing health problems, such as juvenile diabetes, heart disease, and food poisoning, and demand that everyone make way for government to rush to the rescue. But these complicated challenges require solutions that are more thoughtful than the hasty options currently on the table.

Rather than banning saturated fats, trans fats, salt, food dyes, corn syrup, canned tuna, or some other flavor-of-the-month food demon, health authorities should do everything they can to educate consumers about scientifically proven food-related risks to our health.

And then leave us alone.

Salt-rationing and fat-banning will ultimately cause more headaches than health benefits. As Julia Child once put it, “When you’re afraid of your food, you don’t digest it well.”

And although nanny-state food policies are a Big Apple tradition, New Yorkers aren’t the only ones who should be concerned. Salt enforcers and cooking-oil cops will find their way to your town. And then public health – and your health – actually will become everybody’s business.