Published: Oct 27, 2012 12:07 PM EDT
Updated: Oct 28, 2012 6:31 AM EDT

FRESNO, Calif. (AP) - Two decades ago, Mi Pueblo Food Center began as a small butcher shop run by an illegal immigrant. Now, it has grown into a popular chain of 21 Hispanic grocery stores in Northern and Central California.

But the company is under fire from an ongoing immigration audit and its decision to use a controversial federal program that screens the eligibility of new employees to work in the U.S.

The union organizing Mi Pueblo' 3,200 workers is also leading a consumer boycott against the company.

Experts say immigration audits - an Obama administration alternative to immigration raids - can cause a dilemma for companies that cater to immigrants.

They have to fire workers who lack employment authorization, but can also face the ire of the community and labor unions.