diff --git a/chrome/content/zotero/xpcom/translation/translate.js b/chrome/content/zotero/xpcom/translation/translate.js
index de3cd856dd..5ffc1e0a24 100644
--- a/chrome/content/zotero/xpcom/translation/translate.js
+++ b/chrome/content/zotero/xpcom/translation/translate.js
@@ -93,8 +93,11 @@ Zotero.Translate.Sandbox = {
 			if(translate._libraryID === false || translate._parentTranslator) {
 				// remove null, undefined, and false properties
 				for(var i in item) {
-					if(!item[i] && item[i] !== 0) delete item[i];
-					if(typeof item[i] === "string") item[i] = item[i].trim();
+					if(!item[i] && item[i] !== 0) {
+						delete item[i];
+					} else if(typeof item[i] === "string") {
+						item[i] = item[i].trim();
+					}
 				}
 				
 				translate.newItems.push(item);