diff --git a/util/feeding.py b/util/feeding.py
index 645b78ae..69069e4f 100644
--- a/util/feeding.py
+++ b/util/feeding.py
@@ -87,7 +87,7 @@ class DataSet(object):
         self.next_index = next_index
         self.files = None
         for csv in csvs:
-            file = pandas.read_csv(csv, encoding='utf-8')
+            file = pandas.read_csv(csv, encoding='utf-8', na_filter=False)
             if self.files is None:
                 self.files = file
             else: