One of two federal inspectors who contracted swine flu while investigating an outbreak on an Alberta pig farm flew on a commercial flight to Winnipeg shortly after being infected, CBC News has learned.

Two CFIA staffers got sick a day after taking nasal and blood samples from pigs in a barn on this central Alberta farm. (CBC)

The inspectors took nasal and blood samples from pigs on a farm near Rocky Mountain House for two hours on the night of April 28.

One of the Canadian Food Inspection Agency workers travelled to the federal virology lab in Winnipeg to personally deliver samples of the H1N1 virus from the quarantined barn.

It is unclear what flight the worker took, whether the worker was displaying symptoms at the time or whether he or she infected anyone else.

The two workers wore protective gear during the April 28 inspection, but a report by Alberta Health Services obtained by CBC News said they did not have the right equipment and had not been instructed in proper procedures.

The union representing the inspectors blamed the CFIA for the situation, saying the workers became ill because they weren't trained in proper decontamination procedures.

"To have people not only people putting themselves at risk, but potentially putting the public at risk, I think is unforgivable," said Bob Kingston, president of Agriculture Union-Public Service Alliance of Canada.

But the CFIA insists any risks to the public were minimal.

"Since the appearance of the pandemic in the general population has produced very little in the way of consequences, people on that plane likely are at very, very low risk of any kind of disease," said the CFIA's Dr. Jim Clark.

About 500 hogs were culled on the Alberta pig farm on May 8, because the animals could not be sold. The animals had been under quarantine since April 28.

Swine flu is transmitted from animal to human mainly on pig farms where farmers and workers are in close contact with live pigs. The virus cannot be contracted through eating pork.

The spread of swine flu from human to human happens in the same way as seasonal flu, through coughing or sneezing.