Recent raids in Minnesota that resulted in the firing of hundreds of Chipotle restaurant workers illustrate how the U.S. Immigration and Customs Enforcement (ICE) has changed its tactics. For years, critics have complained that ICE should target the owners of businesses who illegally hire rather than conducting raids targeted at immigrants. Over the last year, the agency has done just that, criminally charging a record-breaking 180 owners, employers, managers, or supervisors, up from 135 in 2008 and 114 in 2009, according to a report in the Minneapolis StarTribune.

ICE also conducted more than 2,200 I-9 audits in 2010, compared to 1,400 in 2009. Comparing I-9 audits against Social Security and immigration records have resulted in nearly $7 million in fines compared to $1 million in 2009.

Still, critics complain that fired workers are not arrested or deported and will just move on to another job. Chipotle quickly replaced the estimated 700 workers fired in December. ICE officials say that employers can avoid problems by participating in programs such as IMAGE or E-Verify, which allow them to quickly check online their employee’s records against federal records.

But some employers simply resort to cash payments and avoid paying taxes––which illustrates why the federal government needs to develop a plan for comprehensive immigration reform.