The revelation that federal meat inspectors were ordered to ignore carcass contamination at Alberta鈥檚 XL Foods plant reverberated on Parliament Hill Thursday, as opposition parties hammered the Conservative government over its handling of the E. coli crisis that sickened 18 people across Canada.

Agriculture Minister Gerry Ritz is once again under fire, this time over a Canadian Food Inspection Agency memo that instructed beef inspectors at the plant in Brooks, Alta., to ignore visible fecal and intestinal contamination on carcasses being processed for sale to Canadians.

The 2008 memo obtained by 麻豆影视 ordered inspectors to give extra scrutiny to meat being shipped for sale in Japan, however.

鈥淥ur number 1 priority is to ensure this standard is met with Japan eligible carcasses,鈥 said the memo, written by a CFIA meat hygiene supervisor at the plant.

The CFIA reversed that policy only two weeks ago, when it sent a new memo telling inspectors to halt the meat production line and remove any spotted contamination on carcasses.

The news exploded in the House of Commons during question period Thursday, as the Conservatives fielded attacks over the CFIA鈥檚 2008 directive. Some called for Ritz鈥檚 resignation, saying the minister has repeatedly failed to address food safety issues.

鈥淭hat minister should have resigned months ago,鈥 said NDP agriculture critic Malcolm Allen.

鈥淲e are talking about fecal material -- please don鈥檛 have me say the other word that begins with an 鈥楽,鈥欌 Allen said at a commons committee. 鈥淲e鈥檙e talking about that on a carcass.鈥

Liberal MP Frank Valeriote said the RCMP should be called to 鈥渋nvestigate what may amount to criminal negligence.鈥

Ritz and the CFIA denied that there is a two-tiered food safety system in place, saying meat being sold to Canadians was just as thoroughly inspected, but later in the production process.

鈥淭he de-contamination system for Canadian consumers, for all other export markets in the world, is further down the line,鈥 Ritz said Thursday.

The president of the federal food inspectors鈥 union said that鈥檚 not true.

Bob Kingston said the meat is later put in a de-contamination shower, but the wash won鈥檛 remove feces from carcasses -- they have to be cut from the meat.

CFIA President George Da Pont, however, insisted that food safety is the agency鈥檚 鈥渘umber one priority.鈥

Prime Minister Stephen Harper also defended the CFIA and his government鈥檚 response to the tainted meat crisis.

鈥淐FIA confirmed the meat sold in Canada is just as safe as exports to other countries,鈥 he said. 鈥淭here are strict food safety standards in this country.鈥

With a report from CTV鈥檚 Ottawa Bureau Chief Robert Fife