The question is self evident in one sense. If you are asking "legally" justifiable, then that too would be self evident (though I don't believe that was the spirit of the question).

If it is worth it to you to pay the potential price, and your family is in danger of becoming malnourished (notice I did not say starving, I do not think any question of morality should impare ones ability to feed his family to the point of survival.), then absolutely it is justifiable (in the moral sense), as would be, the act of stealing food, illegal foraging, etc.

Ask no man this question, ask it of your God, yourself, your wife, your children. Then decide and face the results of your decision.