MINNEAPOLIS // Jim Tonjes was high above North America when he bit into a hot turkey sandwich aboard a Delta Air Lines flight and felt a sudden jab in his mouth.
Glancing down, he noticed what looked like a sewing needle in the food. Another passenger on the aircraft reported the same thing.
At first, he thought a toothpick meant to hold the sandwich together had punctured the roof of his mouth. When he pulled it out, "it was a straight needle, about one inch long, with sharp points on both ends".
Now US and European authorities are trying to determine how the needles got into meals served on at least four Delta flights from Amsterdam to the US and why anyone would place them there.
"We are keeping all options open because at this moment, we have no idea why somebody or something put needles inside the sandwiches," said Robert van Kapel, a spokesman for Amsterdam's Schiphol airport.
The FBI and the airport's police department have opened criminal investigations. The US Transportation Security Administration (TSA) said it does not view the matter as a national security threat.
A Delta spokeswoman said the needles were found in six sandwiches on four flights on Sunday. Passengers discovered four of them. The flights included one to Minneapolis, one to Seattle and two to Atlanta.
Mr Tonjes was returning after a visit to Amsterdam for his mother-in-law's 90th birthday. The nine-hour flight was about 90 minutes from Minneapolis when flight attendants offered Mr Tonjes, who was seated in business class, a cold Mediterranean salad or the hot turkey sandwich.
"I'll be very honest, the first bite, I thought, 'Boy, this is pretty good'," Mr Tonjes said. "It was the second bite that got me."
Now Mr Tonjes is on a 28-day course of medication, which costs US$1,400 (Dh5,140), aimed at warding off any infection, including hepatitis or HIV. His doctors have asked the FBI to immediately tell them if they find any residue on the needle.
The sandwiches were made by Gate Gourmet, one of the world's largest airline caterers, with facilities on five continents.
The company serves many airlines, but only Delta flights appeared to be affected. The company said it was investigating. David Fisher, a spokesman for Gate Gourmet, declined to elaborate.
Kristin Baur, a Delta spokeswoman, said security has been stepped up at all of the Gate Gourmet facilities used by the airline. Delta is also using more prepackaged food.
Even though US airlines no longer serve free meals on domestic flights, the airline catering business is still a big industry. Gate Gourmet provides food for 9,700 flights per day from 122 flight kitchens.
Those kitchens are often not on airport grounds, so meals are taken by lorry to a "sterile" area where planes are parked. The TSA monitors the area in the US and local authorities monitor it at overseas airports.
"Food delivery to airports is a very strict process," said Erroll Southers, a former FBI agent who was the chief of Homeland Security and Intelligence for the police department at Los Angeles World Airports. Lorry drivers get background checks, and "those trucks are inspected for everything from sealed packages to explosive devices".
Gate Gourmet's advertisements for cooks say applicants must be able to pass a criminal-background check. The TSA declined to discuss the security process.
When the needles were discovered on the first Delta flight, a message went out to other Delta flights, which is why some of the needles were found before they got to passengers. The TSA said it "immediately notified all US air carriers with flights from Schiphol to ensure awareness".
On Mr Tonjes' flight, he pushed the flight attendant call button as soon as he found the needle. A few minutes later, another passenger nearby did the same. He said flight attendants offered to call ahead for an ambulance.
"When we landed, it was very, very impressive. When they opened the door, it was flooded with customs agents, police, paramedics and firefighters. It was the whole jetway full of people."