Thanks a lot Viraat.
I wish to clarify my doubt once again. I actually want to record the likelihood of my validation set at the point where the error rate is minimum during training.
Using this likelihood as my reference I want to train my model once again now using  new training set as  combination of both train set and validation set (new train set =  train set old + validation set) and continue training until the new log likelihood of the validation set ( validation set remains same as in the previous case ) matches the old recorded log likelihood of the validation set.