diff --git a/Dockerfile.jetty b/Dockerfile.jetty
index 84422e4..1e8d2dc 100644
--- a/Dockerfile.jetty
+++ b/Dockerfile.jetty
@@ -54,7 +54,7 @@ RUN apt-get update && \
         zlib1g-dev \
         && \
     apt-get autoremove -y && \
-    apt-get clean & \
+    apt-get clean && \
     rm -rf /var/lib/apt/lists/* && \
     rm -rf $GRAPHVIZ_BUILD_DIR
 
diff --git a/Dockerfile.tomcat b/Dockerfile.tomcat
index e4b0b97..1c9493c 100644
--- a/Dockerfile.tomcat
+++ b/Dockerfile.tomcat
@@ -46,7 +46,7 @@ RUN apt-get update && \
         zlib1g-dev \
         && \
     apt-get autoremove -y && \
-    apt-get clean & \
+    apt-get clean && \
     rm -rf /var/lib/apt/lists/* && \
     rm -rf $GRAPHVIZ_BUILD_DIR