ALBERT LEA, Minnesota — America's food inspectors are warning that "unsafe" pork is likely making it to consumers under a change in rules for meat inspection.

That change is now set to roll out nationwide to plants that process more than 90 percent of the pork Americans eat.

"The consumer's being duped," Food Safety and Inspection Service inspector Jill Mauer told NBC News. "They believe that it actually is getting federally inspected when there's no one there to even watch or do anything about anything."

"It's so hard to go to work without feeling physically sick watching this just happen, unfolding in front of you," inspector Anthony Vallone said. "Especially since you took the oath to protect the American people."

Mauer and Vallone have both filed whistleblower disclosure forms with the Office of Special Counsel about their concerns, but this is the first time they’ve spoken publicly. NBC News has spoken to five inspectors in person, over the phone and via email about the pilot program, which eligible pork plants will soon be able to adopt under a change in U.S. Department of Agriculture rules known as the New Swine Inspection System.

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Employees handle sides of pork on a conveyor belt at a Smithfield Foods Inc. pork processing facility in Milan, Missouri, on April 12, 2017. Smithfield foods is one of the five processing plants involved in the pilot program. Daniel Acker / Bloomberg via Getty Images

In traditional plants, as many as seven federal inspectors work on the processing line, handling hog carcasses and checking for defects.

Under the new system, that number will be reduced to two or three federal inspectors who have more experience but who will have limited hands-on interaction with the carcasses.

Instead, the plant's own employees will be checking and sorting the hog carcasses and letting the federal inspectors, called consumer safety inspectors, check their work from a distance. There is no required federal training for those employees.

Finally, the federal limit on line speed — or the rate at which hog carcasses can be moved for processing and inspection — will be removed.

A pilot program for this process, known as HACCP-Based Inspection Models Project, or HIMP, is already in place at five pork processing plants across the country. All five of the Food Safety inspectors interviewed by NBC News have worked at these plants, and four other inspectors who've worked at those plants have expressed similar concerns in sworn affidavits sent to federal regulators.

"If this continues across the nation, when you open your package of meat, what you're gonna get for a pathogen is gonna be a mystery," Mauer said.

Potential defects, according to Mauer, include feces, sex organs, toenails, bladders and unwanted hair.

She and other inspectors claim plant employees with little experience or training are doing minimal checking and sorting in an effort to maintain line speeds and keep plant owners happy.

"They're doing the same job as we were doing in a traditional plant. And we're, you know, verifying them. You can't really see very much in that time. So there's a lot of contamination heading out the door," Vallone said.

The USDA disputes those assertions, insisting that USDA inspectors are free to stop or slow the line if they see any problems.

And the North American Meat Institute supports the rule change, arguing it will improve efficiency while ensuring a safe food supply.

"After more than 15 years of experience with the successful pilot program, NSIS, a voluntary system, still requires USDA inspectors to inspect every animal before harvest and every carcass after harvest to ensure the product is wholesome and USDA always has the authority to affect an establishment's linespeed," institute vice president of communications Sarah Little said.

NBC News also reached out to each of the five processing plants involved in the pilot program. Four referred NBC to the National Pork Producers Council, which in turn referred requests for comment to the North American Meat Institute.

Smithfield Foods issued a statement through Kiera Lombardo, the company's executive vice president of corporate affairs and compliance, that said in part, "I am a mother of two young children and have been part of the Smithfield Foods Family for nearly twenty years. At our company, we produce safe and high-quality food for our consumers that we take great pride in also serving to our own families, mine included."

Food experts and critics say the changes put the public at risk.

"If you're doing things at a much higher rate, you're bound to make mistakes," food safety attorney Bill Marler said. "And if you make mistakes, it's the public that is harmed.”

Although none of the inspectors say they've personally allowed meat that's unsafe or unfit to pass inspection, all are certain that unsafe meat is making it to consumers under the new system.

"At that chain speed, it's hard for any human to identify what they need to," Vallone said. "But, you know, as they push more hogs through the door, and they're not identifying even basic pathology like every inspector does, (there's a) possibility of having pathological hogs into your food source."

FSIS also points to the fact that the pilot program has been in effect for nearly two decades as evidence of its effectiveness.

"For the past 18 years, 15 percent of the pork that consumers have been eating in the United States came from the HIMP plants," FSIS officials said. In that time, they argue, there isn't any evidence that more people have become sick from pork.

Records show there have been no serious public health problems or pork food poisoning outbreaks linked to the test plants, although food safety experts say it's difficult to say that the meat hasn't made anyone sick.

"They say there's no measurable increase in illness, but how do they know that?" Stop Foodborne Illness CEO Mitzi Baum said. "The general public don't know enough about foodborne illness. They think it's 'stomach flu.' So it's very, very difficult to get a real measurement, and that's why the CDC always states that they estimate."

The CDC also says it's difficult to compare foodborne illness rates over time, explaining in an online FAQ that "comparing estimates from 1999 with estimates from 2011 would be meaningless" because researchers used different methods to collect data in the past.

And although the FSIS claims that food safety has improved under the pilot program, a 2013 report released by the Office of Inspector General found that characterization was inaccurate, since the agency didn't study the program for most of its implementation. "Since FSIS did not provide adequate oversight, HIMP plants may have a higher potential for food safety risks," the report said.

For the inspectors who came forward, the issue is a personal one.

"I can't stand silent and watch this go across the nation with the potential of the American public getting contaminated food, adulterated food, and not what they think they're gonna get," Mauer said. "I care that my friends, my family, my loved ones, are gonna eat this product."

The window for plants to apply for the new inspection model opened earlier this month and the USDA says it expects all 35 plants to do so, in addition to the five pilot plants. In total, those 40 plants account for just over 92 percent of the pork Americans consume, according to the USDA.

The Trump administration is looking to allow these same changes for beef processing.