At the end of each epoch, I am getting for example the following output:
Epoch 1/25 2018-08-06 14:54:12.555511: 2/2 [==============================] - 86s 43s/s
I think here is another answer that worth notifying:
val_loss is the value of cost function for your cross-validation data and loss is the value of cost function for your training data
https://datascience.stackexchange.com/a/25269