Jason Alderman was hungry. It was the beginning of his regular Sunday night commute from San Francisco to Boston, but unlike most weeks, he hadn’t grabbed food before boarding his plane. So that June 2018 evening, the public relations executive did something he’d sworn he’d never do again: He ate the in-flight meal.

Sitting in business class, he ordered the duck ravioli after he says the flight attendant assured him it was “very good.” But a few hours later, Alderman knew something was wrong.

“About three-quarters of the way through the flight, I start feeling really bad. Really, really bad,” he recalled. “If you’ve never had food poisoning before, it’s like going 10 rounds with Muhammad Ali.”

Alderman says he managed to reach his Boston apartment before he became violently ill.

He can’t remember how long it lasted. “You sort of get lost in this time warp of misery,” he said. “I got a few hours of sleep, cleaned myself off, took a shower, and went into work. It was probably one of my lower performing days.”

Alderman’s story may carry a familiar ring for many travelers. Jokes and tales about the quality of in-flight meals are nothing new. But just how safe is airline food?

An NBC News investigation of airline catering found an industry with limited oversight where outbreaks are difficult to track. Food safety for airline caterers and airlines is regulated by the federal Food and Drug Administration, which requires inspections of this industry far less frequently than it recommends local health agencies inspect restaurants. When airline food inspections do occur, they can reveal serious safety violations — as many as 22 in a single inspection — but rarely lead to penalties.

Under the FDA’s rules, the agency only has to inspect airline caterers every three to five years. FDA rules for airlines are even looser than for caterers: planes receive random FDA inspections “when time and opportunity allow,” according to an agency manual.

In contrast, the FDA’s food code, which guides the food safety rules adopted by state and local governments, recommends that local authorities inspect food establishments every six months, with exceptions for low-risk facilities. But airline catering facilities don’t always fall under those codes. The FDA considers them different from restaurants because caterers do not sell food directly to consumers, instead contracting with airlines that do.

Some states, like California, do send health inspectors to airline catering facilities. But state and local inspection agencies in multiple states — including those that oversee the cities and counties where both Chicago airports, the Dallas-Fort Worth airport and the Atlanta airport are located — told NBC News that airline caterers were outside their jurisdiction, and only inspected by the FDA.

“Dates of inspection represent only a snapshot of FDA’s engagement with companies,” the FDA said in a statement. “They are not an accurate indicator of FDA’s overall engagement. Between inspections, FDA often engages regularly with companies, particularly regarding corrective actions.”

In the past four years, FDA inspectors have found condensation dripping onto food, fans blowing dust on food, thermometers off by as much as 25 degrees, raw meat contaminating cooked meat, moldy bread, live birds and insects, as well as bird and rodent poop and more at airline catering facilities, according to more than 1,000 pages of inspection reports obtained by public records request.

Whether those violations may have led to illnesses is difficult to say, according to food safety experts. NBC News also found that tracking foodborne illness from airplane food is particularly challenging. First of all, the victims scatter.

“Outbreaks from airline food are very difficult to identify because the people get dispersed into various locations,” said Roy Costa, an environmental health inspector and trainer who has worked as a state food inspector and served as an expert witness in food safety lawsuits.”It’s not like having a cluster of people that you can identify all had one exposure, so it’s difficult to pin them down.”

The Center for Disease Control estimates that 48 million Americans get food poisoning every year. Scientists have identified more than 250 foodborne illnesses ranging from mild to deadly, all with different incubation periods. The most common ones can hit anywhere from 30 minutes after eating to up to four weeks later, according to the CDC. The longer the incubation period, the harder it is to connect it to the food that spread the bacteria.

Travel isn’t the only barrier to discovering potential outbreaks. The systems for reporting illnesses can be confusing to navigate — so even when passengers try to report their illnesses, the stories can fall through the cracks.

‘Oh, it’s negligent’

Airline catering is a nearly $6 billion industry in the U.S. alone, according to an analysis of the industry in the U.S. by market research firm IBISWorld. It is dominated by three companies: LSG Sky Chefs (owned by the German airline Lufthansa and larger than the next two caterers combined), Gate Gourmet and Flying Food Group. Together, they make up nearly half the U.S. market. While a few airlines, like United, do some of their catering in house, most in-flight meals and snacks on major airlines are supplied by catering companies.

Catering facilities are typically on airport grounds, or located within a few miles of the tarmac. After preparation, food is loaded onto narrow carts that fit in airplane aisles, then placed on trucks with hydraulic lifts that take it to waiting planes.

These facilities handle a lot of food. The LSG Sky Chefs building in Chicago, for example, produces 12,000 to 15,000 meals per day, according to a promotional video from earlier this year. Flying Food Group, the smallest of the three major caterers, has 20 facilities around the country and produces 300,000 meals and snacks daily, the IBISWorld analysis states.

LSG Sky Chefs, Gate Gourmet and Flying Food Group told NBC News in similar, separate statements that they are committed to meeting the highest food safety standards, comply with all federal regulations, and undergo internal and external audits. All three said they have taken action any time an issue is identified.

Airlines for America, the trade group for the major North American airlines, said in a statement, “Passenger safety is the airline industry’s top priority, including the health of our passengers and crewmembers. Airline catering providers are subject to a rigorous inspection process, and we work closely with them to ensure that all government food safety standards are met or exceeded.”

Analyzing more than a decade of federal food safety inspection data, NBC News found the FDA has issued at least 1,486 food safety citations to the three major airline caterers and 16 airlines since October 2008, many for serious issues such as failing to keep food at the right temperature and improper sanitization.

The FDA notes companies are expected to respond to violations identified during inspections. “If there are significant violations, the FDA can issue a warning letter, request a recall, or place the food on an administrative hold and have it seized by the U.S. Marshals Service,” it said in a statement. The agency also has the power to “disapprove” a facility if there are no effective enforcement options, preventing it from supplying food for flights.

But its inspection frequency for these companies comes up short in comparison to other food safety programs. Los Angeles County, one of the nation’s largest food safety inspection agencies, has more than 500 health inspectors who visit its 55,864 retail food facilities at minimum once per year. They can go as often as three times annually, depending on the public health risk of a facility.

The FDA has 614 food inspectors. The FDA’s own guidelines note that the three to five-year inspection range for airline caterers should be followed “as resources permit.” The guidance document also states that the time interval is consistent with the federal food safety law. The agency’s citation database only includes inspections where violations were found, making it difficult to determine inspection frequency.

From inspections that do appear in the database, NBC News identified 501 contamination and sanitation-related violations and 36 for failure to keep the facility clear of rodents, flies and vermin for airline caterers and airlines since October 2008. Those types of violations in an L.A. County inspection could result in facility closure and reinspection, according to the county. The FDA has not shut down an airline caterer in that time. For most violations, which the FDA classifies as requiring voluntary fixes, the follow-up occurs during the next scheduled inspection, which could be years later.

In the past two years, inspectors have documented numerous allergen cross-contamination issues and multiple cases of undated and likely-expired food in airline catering facilities. In 2018, an inspector found 1.5-year-old frozen tilapia in the walk-in freezer at an LSG Sky Chefs near New York’s John F. Kennedy Airport.

NBC News also found several violations related to dangerous bacteria in recent inspection reports. During an FDA inspection last year, a Flying Food Group facility in Phoenix tested positive for Listeria monocytogenes, a potentially deadly bacteria that thrives in the cool damp conditions that are common in food processing environments, and is of particular concern for food inspectors. The company had previously found evidence of related Listeria bacteria from their own testing, but did not notify the FDA, in violation of the agency’s rules. The sanitizing room of another Flying Food Group facility in Georgia tested positive for Listeria during a 2017 inspection. An LSG Sky Chefs facility in Denver tested positive for a less-common form of Listeria that year. The year prior, three LSG Sky Chefs facilities issued recalls for food possibly contaminated by Listeria.

“Oh, it’s negligent,” Costa said of the airline caterers, after examining a selection of FDA citations for violations. “What you see here is repeated pattern where they’re not following the rules…It’s very, very clear that they have a potential risk.”

‘Some degree of accountability’

Alderman’s illness last summer fit the pattern of the previous two times he’d had food poisoning years before — one of them in the middle of a trans-continental flight. He never went to the doctor for it, but consulted his wife, a nurse practitioner, who advised him to drink a lot of water and wait for it to pass. It did.

That’s often how food poisoning works — the body reacts violently until it expels the toxins, then recovers. The illness is over so fast that people are unlikely to go to the doctor, adding to the challenge of confirming and tracking food poisoning.

But Alderman said the most disappointing part of the experience was trying to tell authorities what happened.

“I wanted people to know about this so that there could be some degree of accountability, so that they could go and inspect,” he said. “And it feels like that just didn’t happen.”

He said he tried to report his illness to the airline, United Airlines, and the FDA. But the “Report a problem” page of the federal government’s food safety website said to contact his local health inspector. It had instructions for where to report problems with restaurant food or meat, but nothing specific for airplane food. So he emailed the San Francisco health inspector’s office. They told him that the airport he flew out of and its catering facility were actually in the jurisdiction of the San Mateo County health inspector. His complaint was forwarded, according to email records, but he never heard anything else.

In his email to United, Alderman asked, “Do you report this incident to public health authorities?”

A spokesperson for the airline told NBC News it is standard procedure to investigate passenger illness claims fully, but the only response Alderman got was a generic “thank you for your feedback” email and $75-worth of frequent flyer miles.

Frustrated, Alderman also logged his complaint online at iwaspoisoned.com, a crowdsourced website dedicated to tracking foodborne illness outbreaks, which is credited with helping identify several outbreaks in the last five years, including E. coli outbreaks at Chipotles in multiple states in 2015.

The site’s complaint database is a small, non-representative sample. In the past two years, 317 people have shared stories of violent illness they believe was caused by food served on an airplane. More than one-third of those complaints were about flights departing from U.S. airports.

Asked where consumers should report illness from airplane food, the FDA said, “You can report a problem to the FDA online, via phone, or via mail.”

For his part, Alderman said he has learned his lesson. Flying more than 100,000 miles every year, he frequently gets upgraded on flights. But no matter where he sits, he now avoids what’s served unless it is prepackaged. He’s determined not to have another duck ravioli incident.

“If I don’t have time, then I’ll eat a bag of pretzels,” he said, “or I’ll simply twiddle my thumbs and go hungry.”

“No matter how hungry I am, I’ll be touching down in a few hours — I can eat then.”