When Brynwood Partners in 2006 took over the Stella D’oro factory in the Bronx, the Wall Street private equity firm had every reason to believe it would be easy to slash the wages, pensions, holidays and sick pay of the 136 bakery workers.

But the takeover brainos forgot one important fact: The workers are represented by a union, Local 50 of the Bakery, Confectionery, Tobacco Workers and Grain Millers (BCTGM).