Three shipments of Australian beef exported to the United States have been found to contain the potentially fatal E-coli bacteria.
The ABC reports that in the past 12 months, up to 13 shipments of Australian meat have also been rejected by the United States because they contain faeces or other matter.
Greg Reid from Australia's Federal Department of Agriculture says the detection of E-coli is a huge concern, and the three abattoirs involved have been ordered to lift hygiene standards.
Safety monitors have warned that a new inspection system introduced last October, moving away from a high level of government oversight to a more self-regulatory system, is opening the doors for more contaminated meat to be sent overseas.
The US is Australia's second-largest beef export market and largest lamb export market.
The industry says the annual exports are worth more than $1 billion.