Outside the Lines reviewed records at pro sports venues in North America and found food served at them may pose a health risk. (6:58)

Most Cracker Jack boxes come with a surprise inside. At Coors Field in Denver, the molasses-flavored popcorn and peanut snacks came with a live mouse.

A health department inspector found the mouse in a commercial-size bag of Cracker Jack at Coors Field in September 2016, along with five live cockroaches in a trap in a storage room. Two weeks earlier, inspectors had found copious amounts of mouse droppings on a kitchen floor, in food-prep trays, inside a bin of rice and amid bags of cookies that had been chewed. Dead mice were found, and another live one had been found.

Inspectors on both visits cited the Coors Field food locations with high-level health violations -- just a few of thousands of such violations found at North America's 111 NFL, MLB, NBA and NHL venues in 2016 and 2017, according to an Outside the Lines analysis of more than 16,000 routine food-safety inspection reports from local health departments. At about 28 percent of the venues, half or more of their food service outlets incurred one or more high-level violations, the type of unsanitary conditions or omissions that can pose a risk for a foodborne illness.

The violations run the gamut: chicken, shrimp and sushi festering at dangerous temperatures that can breed bacteria; employees wiping their faces with their hands and then handling food for customers; cooks sweating over food; beef blood dripping on a shelf; moldy or expired food; dirty utensils or contaminated equipment; and the presence of live cockroaches and mice. Less serious but still icky: dirty floors, fruit flies, pesky pigeons and, in one venue, beer leaking from a ceiling.

WHAT'S IT LIKE AT YOUR STADIUM? Find your favorite team's venue to determine how many high-level food-safety violations were found, how the stadium's inspection results compare with those of other eateries in the surrounding community and brief descriptions of findings.

The venues with the highest percentage of food outlets that incurred one or more high-level violations in the two-year period include Spectrum Center in Charlotte, North Carolina (92 percent); Palace of Auburn Hills near Detroit, which has since closed, (86.1 percent); American Airlines Center in Dallas, (83.1 percent); and Bank of America Stadium in Charlotte (82.6 percent).

Being slapped with a high-level violation -- often labeled as "critical," "priority" or "major," depending on the jurisdiction -- does not necessarily mean a venue is unsafe or unsanitary. After all, mistakes happen, no matter whether food is being prepped and served at a stadium kitchen, a fast-food outlet or a fine-dining restaurant. But stadium environments carry unique risks because of the large number of people being served in a short period of time, said Patricia Buck, co-founder and executive director of the Center for Foodborne Illness Research & Prevention.

"There will be thousands of people at the stadium and there will be maybe 100 at a restaurant, so the sheer number of people being exposed is going to be higher, so it would tend to be riskier if something like contaminated romaine lettuce was going to be served on a taco," said Buck, referencing the recent E. coli outbreak linked to romaine lettuce that has sickened at least 43 people in 12 states.

Buck said she does not eat at sports venues because "it just seems to be a very chaotic situation where food is being prepared."

Concessions at pro sports venues are a $2 billion industry, according to the National Association of Concessionaires. Although most health departments use some version or adaptation of the U.S. Food and Drug Administration Food Code or a comparable code in Canada to enforce proper food-service practices, the specific food-safety violations and the number cited by inspectors varies depending upon the diligence of the inspection agency or inspector. Some venues get inspected multiple times a year, whereas others might go more than 12 months with few, if any, visits by the local health department. At Washington, D.C.'s Capitol One Arena -- one of four venues not included in the Outside the Lines rankings due to a lack of data -- there were no routine inspections in 2016 and just one routine inspection of a suite kitchen in 2017, for example.

To try to compensate for such jurisdictional differences, Outside the Lines also used data from Hazel Analytics, a Seattle-based company that provides data and analytics of food-safety inspection reports, showing the average number of high-risk violations per inspection for food service outlets and restaurants in a stadium's surrounding community for the 82 venues for which comparison data were available. Among those, 73 performed better than or as well as the community average, while nine performed worse.

Arash Nasibi, chief executive officer of Hazel Analytics, said he expects stadium outlets to perform better because, in some jurisdictions, health departments notify stadium operators when they are planning an inspection because of stadium-access restrictions and security concerns. He said most concession stands inside sports venues serve simple menus with much of the food precooked.

In 2010, Outside the Lines performed a similar analysis of food safety at sports venues, and the results were largely the same, although the methodology used and venues operating at the time were slightly different. In August 2017, Sports Illustrated published a story about violations at professional baseball stadiums, although SI used a different metric than Outside the Lines.

Some fans have not been shy about sharing digestive distress on social media. In April 2016, the Twitter account @thekatzmeow shared this image and sentiment: "Thanks for the memories ... and the listeria. @Mets #NikonMets #FreeBurger?" Owen Katz (@thekatzmeow)

One venue that ranked at the bottom for food-safety compliance in both reports was Tropicana Field, home of the Tampa Bay Rays, which, until this year, had a contract with Centerplate, a concession and food service provider headquartered in Connecticut.

In December 2017, the Rays sued Centerplate for breach of contract, alleging that the contractor "surreptitiously cut corners, underreported gross receipts, concealed performance issues, underpaid the Rays, and underperformed" under their agreement to the "detriment of the Rays and their fans." The lawsuit referenced negative media coverage, including the Sports Illustrated and Outside the Lines stories, noting that within a week of the latter, "a Centerplate supervisor took two cups out of a spoilage container, washed them out and added the dirty cups to a new stack."

The Rays allege that the resulting media coverage of the food-safety violations -- among other issues with Centerplate -- tarnished the Rays' brand and caused the organization financial harm. In its response filed in federal court, Centerplate called the lawsuit "corporate blackmail" and "factually meritless." Centerplate countered that the Rays filed the lawsuit shortly before the contract's expiration to force the concession company to forgive the Rays' "significant debt" and that most of the Rays' breach-of-contract claims fell outside a five-year statute of limitations. The lawsuit is pending.

The Centers for Disease Control and Prevention estimates that 48 million people get sick, 128,000 are hospitalized and 3,000 die from foodborne disease each year in the United States. But it's unknown how often people get sick from food served at sports venues alone, because food poisoning -- regardless of where it occurs -- often goes underreported because people mistake it for the flu or believe that symptoms, such as vomiting, diarrhea or stomach cramps, don't require medical attention or formal reporting.

Although some contaminants can make people sick right away or shortly after eating, others, including several types of bacteria or viruses, might not trigger symptoms until several hours or even days later. By that time, many fans have returned to their homes, miles from the stadium or arena where they attended a game, making an illness even more difficult to trace, health inspectors told Outside the Lines.

Some fans, however, are not shy about sharing digestive distress on social media, often including photos and tagging the social media accounts of the team.

In April 2016, Twitter account @thekatzmeow shared a photo of a hamburger in a moldy bun with Citi Field in the background: "Thanks for the memories...and the listeria. @Mets #NikonMets #FreeBurger?" Another Twitter post, from @melissaggeorge in September 2017, tagged the Chicago Cubs' account and read, "@Cubs my husband and 6 year old woke up at 1:30am puking their guts up. #checkthehotdogs #food-poisoning."

On July 4, 2017, Laurence Leavy took to Twitter and Instagram to post about friends of his who got sick after attending a Yankees game at Yankee Stadium the night before. "Anybody else get food poisoning from Legends Buffet @Yankees from seafood last night? Blood work from hospital confirms bacteria poisoning," read one tweet. "Possible At least 4 people got food poisoning from @Yankees legends buffet. @Yankees silent," read another.

One of my guests to @Yankees Legends buffet last night got food poisoning and is at hospital today. Anyone else? pic.twitter.com/XbwJkmZNd2 — Marlins_Man (@Marlins_Man) July 4, 2017

Leavy is better known to sports fans as "Marlins Man." At baseball games, he is often seen positioned behind home plate, and the July 3, 2017, game at Yankee Stadium was no exception.

Leavy said he took nine people to the game, and two fell ill overnight and into the morning on a flight to Miami. One of them went to the hospital, he said. In a recent interview with Outside the Lines, Leavy read from a notepad he said he saved from that day.

"This is what they were saying: They were doubled over, they were vomiting, had cramps, headaches, felt like their appendix needed to be taken out," he said. The one who ended up at the hospital, "thought she was going to die, she was that sick. She missed three days of work. She did not eat for three days." The other woman stayed home from work for two days, he said.

Both women confirmed Leavy's account in conversations with Outside the Lines. The woman who went to the hospital said doctors told her she had food poisoning based on her bloodwork, but she said she did not recall if they identified a specific virus or bacteria.

Meanwhile, Leavy was starting to hear from other fans via social media who also claimed to have fallen ill at the game. He spoke to three people on the phone and asked them about where they ate and when they ate there, and compared their stories to that of his two friends, he said. Based on that, he said he believed that they were all sickened by the shrimp cocktail sauce on a seafood buffet for VIP guests. Leavy, who said he's allergic to seafood, didn't eat from the buffet and didn't fall ill.

Leavy said he kept in touch with the food and beverage staff at the stadium and passed along the names of the other fans with whom he'd corresponded. He said a woman from the food and beverage staff assured him they were taking his report seriously.

Leavy said he received a call from someone who identified himself as an inspector with the health department, but the New York City Department of Health and Mental Hygiene has no such record of any complaint of foodborne illness at Yankee Stadium from Leavy, any other individual, or anyone associated with Legends or the Yankees. Under New York City law, food establishments are required to report any suspected cases of foodborne illness to the health department. Failure to do so could result in the issuance of a violation subject to a fine.

On July 4, 2017, Laurence Leavy took to Twitter and Instagram to post about friends of his who got sick after attending a Yankees game at Yankee Stadium the night before. Al Diaz/Miami Herald/TNS via Getty Images

Jennifer Bozzelli, a spokeswoman with Legends, said that the company had been aware of a complaint from one of Leavy's guests but that Legends had done a "full investigation and found that the source was not from Yankee Stadium." Upon her request, Outside the Lines sent a detailed list of questions -- including whether anyone at Legends reported the incident to the health department.

In response, Bozzelli instead issued a statement without answering the questions, which read in part: "The health and safety of our guests is paramount to us, and we adhere to the strictest of safety standards to ensure that only the best quality of food is served in accordance with all health department standards. We have invested significant resources, including but not limited to strict policies, procedures and training to ensure the equipment and preparation of our food meets those high safety standards."

When asked whether Legends was issued a violation and/or fine in connection with this incident, a New York City health department spokesman wrote in an email that the department "investigates suspected cases of foodborne illness and pursues enforcement action as appropriate." The spokesman instructed Outside the Lines to file an open records request for any such violations, and a response Dec. 4 revealed no record of any such violations.

In the Outside the Lines analysis, 79.1 percent of the outlets at Yankee Stadium had one or more high-level violations over 2016 and 2017, with only five other sports venues having a higher percentage. Yankee Stadium, however, performed better overall than New York City's average of high-level violations per inspection at all food establishments.

In Leavy's case, he said he believes his friends fell ill from the same source as the strangers he connected with via social media. But when multiple fans in the same group get sick after attending a sporting event, health inspectors say it's possible they could have been sickened by something they ate earlier in their trip.

Such was the dilemma faced by the University of Wisconsin marching band after a visit to Indianapolis on Dec. 3, 2016, when the band played at Lucas Oil Stadium for the Big Ten championship game between Wisconsin and Penn State.

According to a complaint to the Marion County Public Health Department in Indianapolis, 19 band members became ill with vomiting and diarrhea, with the first report coming in at 7:45 p.m., shortly after the band had eaten boxed lunches containing sandwiches, chips, cookies and apples provided by the stadium food service staff.

Only someone familiar with the band's formation would have noticed the handful of students missing from the halftime performance who were being tended to by stadium paramedics, said Darin Olson, assistant director of bands. Several other band members powered through the halftime show despite not feeling well, he told Outside the Lines.

"It was challenging," Olson said. "The second they got off the field, they decided they would get looked at."

Olson said the school chartered a separate bus for the sick students' trip back to Madison, Wisconsin. Olson paused when asked to recall the five-hour ride home: "It was ... as you can imagine."

Marion County (Indiana) health department spokesman Curt Brantingham said it is suspected that the band members had norovirus, a common virus associated with food poisoning. Brantingham said that a two-week investigation after the complaint did not find a link between the illness and any place the band members ate during their trip, and "no definite conclusion was found as to the source of the illness."

The inspection report that followed the complaint revealed a history of good food-safety practices at the stadium and no current violations. Also, none of the other groups that consumed the meals reported any illnesses, the report stated.

In some of the complaints reviewed by Outside the Lines, health department inspectors did find violations when they visited the suspected location or venue. When an inspector arrived at a kettle corn outlet at Coors Field in August 2017 in response to a fan reporting being ill after eating kettle corn, the inspector saw an employee repeatedly eating kettle corn from the hopper with gloved hands and not removing the gloves or washing his hands, which were critical violations. At Coors Field, 71.2 percent of the food outlets had one or more high-level food-safety violation in 2016 and 2017, though the venue overall performed better than the surrounding area's average of high-level violations per inspection at food establishments.

Although it's not as headline-grabbing as moldy buns, mouse feces or crawling cockroaches, improper handwashing is actually the top contributor to the spread of foodborne illness. Sports venues can have unique challenges in that regard, said public health specialist Sara Liggins Coly with the Oklahoma City-County Health Department.

Some sports venues get inspected by local health departments multiple times a year, whereas others might go more than 12 months with few, if any, visits. Hunter Martin/Getty Images

Venues often employ temporary workers, she said, and many also allow nonprofit organizations to run concession stands as fundraising events. As a result, there might be food service workers who are not fully aware of food-handling rules -- including proper handwashing -- or who are unaware how to properly clean equipment, she said.

"It's an ongoing education battle of telling people what the proper procedures are, as opposed to you maybe dealing with the same person in a one-stop-shop establishment compared to arena-style inspections," said Liggins Coly, who inspects Chesapeake Energy Arena, home to the NBA's Oklahoma City Thunder. At Chesapeake, only 18.4 percent of the locations were cited with a high-level violation over 2016 and 2017, and it performed better than the community average.

Handwashing can factor in in unexpected ways, such as someone's bare hands coming into contact with ice while scooping it out of an ice machine, Liggins Coly said. That can be a big problem at stadiums, where people often drink more than they eat.

"Many people don't even know that ice is food," she said.

One confirmed case of foodborne illness at a sports venue stemmed from contaminated water used to supply ice for fans at the 1987 University of Pennsylvania-Cornell football game in Philadelphia. More than 158 students -- band members, football players and spectators -- reported symptoms of gastrointestinal illness, according to the CDC.

Liggins Coly added that a sports venue's off-and-on operation can also cause problems for equipment designed to keep foods hot or cold, and a stadium's size and multiple doors and openings can make bug and rodent control a challenge.

Ed Gilaty, senior vice president of risk management and sanitation for Levy, which has more concessions and food contracts with professional sports venues in North America than any other food service or concession company, wrote in an email to Outside the Lines that workers at each of his company's venues partner with local health departments and third-party experts to "develop nuanced approaches to developing safe practices and standards" to comply with federal, state and local requirements.

"Levy has a comprehensive food safety training program at all of our locations, training all team members on employee health and personal hygiene, time and temperature controls, and preventing contamination," he wrote, adding that temporary employees and nonprofits' volunteers receive the same level of training to "ensure the highest level of sanitation for our guests."

According to inspectors' notes and interviews with inspectors, most violations at sports venues are the result of mistakes or oversights and not blatant or intentional acts of malfeasance, such as was displayed in a video that went viral on social media earlier this year of a food service worker at Comerica Park in Detroit spitting on a pizza that would later be served to fans at a Tigers game. The worker pleaded guilty to one felony count and one misdemeanor count of food law violations.

"It was appalling," said Liggins Coly after watching the video. "That leads to a biological hazard. Let's say that he had norovirus, shigella, E. coli, or even Hepatitis A. It's unfortunate that people would do things like that, and it's something that I wouldn't want to deal with as a health inspector."

To learn what is typically involved in monitoring food safety at a sports venue, Outside the Lines followed an inspector from the Environmental Services Department in Wake County, North Carolina, through the kitchen and a concession stand at Raleigh's PNC Arena as workers prepared for an Oct. 30, 2018, hockey game between the Carolina Hurricanes and Boston Bruins.

Thomas Jumalon's official title is environmental services team leader. But it's easier to think of Jumalon as a clean-freak houseguest. The way Jumalon demonstrates proper handwashing makes it seem as though he's preparing to take a scalpel to a patient for surgery rather than to stick a thermometer in a smoked brisket to check its temperature.

Thomas Jumalon, environmental services team leader at the Environmental Services Department in Wake County, North Carolina, during an inspection at Raleigh's PNC Arena. ESPN

"All right. Excellent. Thirty-nine degrees," he said, inspecting the stack of meat in the main kitchen's walk-in refrigerator. "OK. So, his cooling process works, for all intents and purposes, as it should."

Jumalon goes through each section of the kitchen explaining the importance of proper temperatures, equipment cleaning, chemical storage, separation of raw and cooked foods, and a multitude of other rules directly related to the risk of toxins, bacteria and viruses.

He pulls a bag of spinach off a shelf because there was no date written on the package.

"All right, so we'll toss that. When you've got cut leafy greens that are opened up, rules require them to be date marked," he said, which helps to know how long it's safe to keep before it risks harboring bacteria. "Whatever bacteria is there, the moisture in here will support that bacteria to grow. So, that's why we always want to make sure we control the date marking."

Jumalon enters the dry storage area and spies a giant metal can of pizza sauce with a large dent.

"We want to make sure that we don't have anything like this. That should never have been accepted. ... This is a good way to introduce botulism into a produce," he said, and hands the can to the chef to set aside for disposal. "You can have immediate paralysis, long-term paralysis. It is a neurotoxin and it will kill you."

Jumalon's thoroughness is backed up by the data from Hazel Analytics showing that Wake County inspectors issued more high-level violations per inspection than all but one other health department included in the analysis.

In the Outside the Lines analysis, 68 percent of the outlets at PNC Arena were cited with one or more high-level violations in 2016 and 2017, but the arena performed substantially better than the community average.

Despite the handful of issues, Jumalon points out at PNC Arena's main kitchen -- which prepares foods as different as salmon and bread pudding as well as its trademark house-smoked brisket -- he said the arena typically scores well by Wake County standards, having received a 97 percent, an A grade, on the main kitchen's June 22, 2018, routine inspection. But, he said, that's still no guarantee all food is safe.

"I can have one and a half points taken off because I have ... raw hamburger that's above ready-to-eat salad," he said. "If everything else is OK, I've got 98 and a half. I got an A. It's OK, when in essence it's not. ... I can have an A grade and still have things that are bad that can get you sick."

PNC Arena is one of the few major pro-sports venues in North America to essentially run its concessions in house, under a company called VAB Catering, and not on contract with one of the major national food service companies.

Chris Diamond, vice president of VAB Catering, said he is someone who looks for a health department rating as soon as he walks into a restaurant, but he said it's important to do further research to see exactly which violations contributed to a location's score, stressing that it could be a few little things that add up.

As Diamond stood in the concourse answering a reporter's questions, he watched fans stepping up to a concession stand that scored a perfect 100 on its last inspection -- a rating noted on a health department sign placed overhead.

"We're pretty proud when somebody sees a 100 when they walk into a concession stand," Diamond said. "And if the food's good, it's even better."

Sandra Fish is a Colorado-based freelance researcher. Simon Baumgart, a producer in ESPN's investigative unit, contributed to this report.