As a high school teacher from Timmins, Ont., sat down for breakfast with his kids Monday morning, he had no idea the box of Frosted Flakes he was about to open was the last one to ever be produced at the London Kellogg's plant.

"We opened up the box, and on the wax bag on the inside we noticed there was something written," said Stephane Gaudette.

He removed the bag from the box in fear it may have been tampered with.

"I saw there was something written on the bag," explains Gaudette. "I said, 'What's this?' because it was written in sharpie, in black marker. I said 'This is odd.'"

When he pulled the plastic bag from the cardboard box there was a handwritten note on the bag.

"[It said] this was the last box made at the London, Ont., plant at Kellogg's, on Dec. 5, 2014," said Gaudette. "We were getting a history lesson right there."

Saw significance right away

Gaudette said the note was signed by three men, with more than 20 years of experience, but said he couldn't quite make out their full names.

"I saw the significance of it right away," he said. "I thought this is really, really special. My heart was going out to the folks at Kellogg's, because I have been to London before, and I knew the significance of that plant, I had heard about the closure just before Christmas."

The company had been in London for 100 years. The plant, which closed in December, 2014 was 75 years old and had made more than 20 different products and packaged them all in-house.

The plant's closure put 500 people out of work.

Union officials said the plant was closing because cereal sales were down.

Special for people of London

Gaudette said he told his kids they were not going to open up the bag, because it "must be special for the people of London."

He doesn't know yet what he's going to do with the box and bag.

"We're going to talk it over with the kids, but I know it's something near and dear to Londoners," Gaudette said. "It's a piece of Canadian history, I would imagine. I might keep it for a while. It would be a great conversation piece for a while … maybe the children will get a scholarship at Western University."

Gaudette said he'd love to meet the workers who packaged the last box and left the note on the bag.