Steve Brown remembers what he calls the fateful day more than three years ago when he had "the fateful sandwich."

Initially, he was OK — and then the headaches started.

"It felt like somebody was inside with their feet up against the back of my eyeballs trying to kick them out of my head," he says, seated in the dining room of in his home near Haliburton, Ont. "It was the most excruciating pain I'd ever felt."

Brown was one of thousands of people who became ill in 2008 after eating meat contaminated with listeria from a Toronto-area Maple Leaf Foods processing plant. At least 23 people died.

During the crisis, the Canadian Food Inspection Agency attracted most of the attention.

But the Public Health Agency of Canada is also an important player when it comes to food safety. After the listeriosis crisis, it began collecting more data from the provinces and territories, including instances of laboratory-confirmed listeria infections.

But the agency also relies on other programs to collect data to spot trends before they develop into full-blown crises such as listeriosis.

One such program goes by the name C-EnterNet.

Designed in 2005, it was conceived as a program that would collect food-safety data from five so-called sentinel sites situated across the country. The sites were intended to provide the agency enough information to spot trends in certain illnesses.

Most food-borne illnesses don't show up in major recalls that frequently make headlines. But if the agency notices certain patterns in different parts of the country, it can take steps to prevent a greater of number people from getting sick.

However, more than six years later, only two sites are in operation, and a department audit has warned that without the full complement of five sites, the program cannot make the statistical comparisons needed to track patterns for food-borne disease.

Based on U.S. model

The C-Enternet program was patterned after Foodnet, a similar program in the United States run by U.S. Centers for Disease Control and Prevention. Foodnet has 10 sentinel sites, covering about 15 per cent of the U.S. population, and produces regular reports based on its findings.

"In our vital signs report last year, we showed how e-coli infections had decreased by almost 50 per cent and looked at some of the reasons that had led to that decrease, and then contrasted that with salmonella, which had not decreased," the CDC's Barbara Mahon said in an interview with CBC News.

"And we discussed ways in which some of the approaches that had been so effective could be used so that we could work together to try to reduce salmonella and other food-borne illnesses."

There are concerns that in Canada the public health agency's C-Enternet program may be unable to produce similar results.

In 2009, a government audit concluded that "without a network of [five] sentinel sites as envisioned in the original program design, data are not as statistically powerful, cannot be used for comparisons across regions and cannot generate national estimates."

Health Minister Leona Aglukkaq, who is responsible for the public health agency, says there are no "timelines" for getting money for three more sites.

Without the full complement of five sites, says Rick Holley, who teaches food safety at the University of Manitoba, the agency is "shooting in the dark" when it comes to tracking food-borne illnesses.

Still feeling effects

Listeria was not on the public health agency's radar when Steve Brown got sick in 2008.

The headaches landed him in the Kingston General hospital, where he almost died. There was "probably a 50-50 chance that his brain stopped working and it wouldn't let his lungs work properly," said Scott Coles, Brown's family physician for 10 years. "He was pretty sick."

Brown was felled by a condition called listeria rhombo encephalitis, which is listeria infecting the brain, particularly in the cerebellum, the brain stem area that controls the balance centre and various other things.

Brown says he's feeling better — sort of — 3½ years after eating his "fateful" sandwich.

Brown has stopped driving, riding his motorcycle with his wife, Helen, and playing the guitar. Because he has problems with balance, he gave up his job as a contractor. He now hopes to earn a living building decks in the picturesque Haliburton region.

"If I can't make a living at that then I guess I'll be basket weaving," he said. "I have to maintain a sense of humour. That's helped me though a lot of this. I've been able to laugh at myself. Sometimes it hasn't been an easy laugh."