diff --git a/Library/Homebrew/cmd/audit.rb b/Library/Homebrew/cmd/audit.rb
index bd86135ebc..34c4a624b5 100644
--- a/Library/Homebrew/cmd/audit.rb
+++ b/Library/Homebrew/cmd/audit.rb
@@ -424,7 +424,7 @@ class FormulaAuditor
       problem "Use \"\#{ENV.cxx}\" instead of hard-coding \"#{$3}\""
     end
 
-    if line =~ /system\s+['"](env|export)\s+/
+    if line =~ /system\s+['"](env|export)(\s+|['"])/
       problem "Use ENV instead of invoking '#{$1}' to modify the environment"
     end