It has languished for quite some time since the state of Vermont passed what was effectively the first mandatory GMO labeling law in the country back in 2014, but a federal voluntary version has finally been approved by Congress.  The Senate passed the bipartisan Roberts-Stabenow bill on a 63-30 vote last week and sent the bill for further consideration to the U.S. House, which on a vote of 306-117, passed the measure yesterday and sent it to the President.  The Vermont mandate, which went into effect July 1, mandates specific language on all food packages containing ingredients derived from GMOs, while the version approved by Congress yesterday offers manufacturers three options (straightforward language, digital codes or a symbol to be developed later) from which to choose.  If President Obama signs the bill as he is expected to do, the federal legislation will effectively nullify the Vermont mandates.