According to the Ottawa Citizen, public health officials have found Salmonella typhimurium in frozen ground beef and Salmonella Heidelberg in raw chicken samples taken from a Lunch Lady franchise that has been linked to an outbreak. At least 50 illnesses in about a dozen elementary schools serviced by the business have been identified.

Lab tests indicate that an outbreak of salmonella that has sickened 46 children likely came from food served by a lunch caterer that primarily serves schools, according to the city’s health department.

Samples of frozen ground beef and raw chicken taken from a kitchen belonging to a Lunch Lady franchise on Boyd Avenue tested positive for the stomach bug detected in the children and four adults who’ve been sick enough to seek medical attention in the last two weeks, the department said in a Friday evening statement.

“The results further point to a link between the outbreak and the ground beef prepared at the caterer, but additional testing is still underway,” the statement said.

The beef was tainted with salmonella typhimurium and the chicken with salmonella heidelberg, it said, two of the many, many forms of the bacteria. The department’s investigation has pointed particularly to Lunch Lady meat lasagna and beef tacos as foods eaten by people who later got sick.

The challenge now is to determine whether the meat was contaminated when it arrived at the kitchen or became tainted while Lunch Lady workers handled it. The health department “is in communication with the Provincial and Federal Health and Food Safety authorities to assist in the ongoing investigation and response,” the statement said.

According to public records, the Boyd Avenue kitchen has been inspected four times since news of the outbreak became public and received a clean report each time, but it could have been just one worker with dirty hands who spread the infection. The kitchen is staying closed, the health department said.

Four post-outbreak inspections may not be all that representative of what was going on before the cluster of illnesses was identified. Undercooking or cross-contamination between the raw food sources and ready-to-eat foods are potential pathways for the Salmonella. What’s unclear from the public health statement is whether either of the strains found are the same as what has been seen in the cluster of illnesses.