diff --git a/public/flexiprep/src/main/scala/nl/lumc/sasc/biopet/pipelines/flexiprep/Cutadapt.scala b/public/flexiprep/src/main/scala/nl/lumc/sasc/biopet/pipelines/flexiprep/Cutadapt.scala
index 564bb4427a87f65bf97ea06667a505219423cfcd..55f9644511dead6aa2cf8733752e14b6238dc07c 100644
--- a/public/flexiprep/src/main/scala/nl/lumc/sasc/biopet/pipelines/flexiprep/Cutadapt.scala
+++ b/public/flexiprep/src/main/scala/nl/lumc/sasc/biopet/pipelines/flexiprep/Cutadapt.scala
@@ -74,7 +74,7 @@ class Cutadapt(root: Configurable) extends nl.lumc.sasc.biopet.extensions.Cutada
       "num_reads_affected" -> stats("trimmed"),
       "num_reads_discarded_too_short" -> stats("tooshort"),
       "num_reads_discarded_too_long" -> stats("toolong"),
-      "adapters" -> adapter_stats
+      "adapters" -> adapter_stats.toMap
     )
   }