After an investigation by the CBC's The Fifth Estate alleged that a disproportionate number of clerks and retailers win large lotteries in Ontario, the province's gaming corporation has defended its security practices.

"It is critical to note that when a retailer/clerk wins a major prize, [Ontario Lottery and Gaming Corporation] conducts an investigation 100 per cent of the time," said a statement released Wednesday.

Ontario lottery tickets.
(Robin Rowland/CBC)

"Each case is thoroughly investigated by our internal staff. If OLG believes there is a serious concern with a lottery prize claim, the police are contacted."

Police have been contacted four times in the past five years, said the corporation, adding that two of those instances were for information purposes.

Ontario Minister of Public Infrastructure David Caplan said he has asked for a review of OLG security procedures.

The CBC report, which aired Wednesday night, says of the roughly 60,000 lottery ticket sellers in Ontario, retailers won nearly 200 times in the past seven years, with an average prize of $500,000.

A statistician with the University of Toronto called those numbers a statistical anomaly, saying there is a "one in a trillion, trillion, trillion, trillion" chance of that many retailers winning. Dr. Jeffrey Rosenthal said the number of wins should be closer to 57.

Security measures above standard: OLG

The lotto corporation said it uses a number of security measures that "meet or exceed measures in place in every other province and almost every state in the U.S.A."

They include screens on lottery terminals that face the customer, music signalling a win, technology that freezes a terminal when a large prize-winning ticket is validated and self-serve ticket checkers for people to check their own tickets.

• The statement also offered tips for ticket-buyers, saying they should:
• Sign the back of the ticket.
• Check the number online, in newspapers or on television.

Make sure they get their ticket back, along with the validation slip.

The corporation also said it uses an auditing firm to annually review the system and has a new vice president of security to oversee its investigations procedures.

The lotto corporation said it stands by its ticket retailers.

"We continue to stand by the hard-working men and women who rely on convenience stores for their livelihood, and who like the majority of the population are by and large honest, dedicated people," said the statement.