diff --git a/Laptop/AimMembers.cpp b/Laptop/AimMembers.cpp
index 57f040921..6bc2d0c58 100644
--- a/Laptop/AimMembers.cpp
+++ b/Laptop/AimMembers.cpp
@@ -5650,7 +5650,7 @@ void EnableWeaponKitSelectionButtons()
 					{
 						bShow = true;
 						//shadooow: if any of the item in kit is limited to specific system and this system isn't enabled then disable the whole kit from selection
-						if (((Item[usItem].usLimitedToSystem & 1) && !UsingFoodSystem()) || ((Item[usItem].usLimitedToSystem & 2) && !gGameExternalOptions.fDisease))
+						if (((Item[usItem].usLimitedToSystem & FOOD_SYSTEM_FLAG) && !UsingFoodSystem()) || ((Item[usItem].usLimitedToSystem & DISEASE_SYSTEM_FLAG) && !gGameExternalOptions.fDisease))
 						{
 							bShow = false;
 							break;
diff --git a/Tactical/Item Types.h b/Tactical/Item Types.h
index d156853c0..3e91212c0 100644
--- a/Tactical/Item Types.h	
+++ b/Tactical/Item Types.h	
@@ -947,6 +947,10 @@ extern OBJECTTYPE gTempObject;
 // autofiretohitbonus,
 // bursttohitbonus
 
+// bitflags for usLimitedToSystem
+#define FOOD_SYSTEM_FLAG		1
+#define DISEASE_SYSTEM_FLAG		2
+
 typedef struct
 {
 	UINT32		usItemClass;
diff --git a/Tactical/Items.cpp b/Tactical/Items.cpp
index 7eb25bc3f..40f165f6d 100644
--- a/Tactical/Items.cpp
+++ b/Tactical/Items.cpp
@@ -1283,7 +1283,7 @@ BOOLEAN ItemIsLegal( UINT16 usItemIndex, BOOLEAN fIgnoreCoolness )
 	}
 
 	//shadooow: exclude also any item that is limited to specific system and this system isn't enabled
-	if (((Item[usItemIndex].usLimitedToSystem & 1) && !UsingFoodSystem()) || ((Item[usItemIndex].usLimitedToSystem & 2) && !gGameExternalOptions.fDisease))
+	if (((Item[usItemIndex].usLimitedToSystem & FOOD_SYSTEM_FLAG) && !UsingFoodSystem()) || ((Item[usItemIndex].usLimitedToSystem & DISEASE_SYSTEM_FLAG) && !gGameExternalOptions.fDisease))
 	{
 		return FALSE;
 	}
diff --git a/Tactical/ShopKeeper Interface.cpp b/Tactical/ShopKeeper Interface.cpp
index 39df11ef0..cc7bc8bb6 100644
--- a/Tactical/ShopKeeper Interface.cpp	
+++ b/Tactical/ShopKeeper Interface.cpp	
@@ -2901,7 +2901,7 @@ BOOLEAN DetermineArmsDealersSellingInventory( )
 		}
 
 		//shadooow: do not sell any item that is limited to specific system and this system isn't enabled
-		if (((Item[iter->object.usItem].usLimitedToSystem & 1) && !UsingFoodSystem()) || ((Item[iter->object.usItem].usLimitedToSystem & 2) && !gGameExternalOptions.fDisease))
+		if (((Item[iter->object.usItem].usLimitedToSystem & FOOD_SYSTEM_FLAG) && !UsingFoodSystem()) || ((Item[iter->object.usItem].usLimitedToSystem & DISEASE_SYSTEM_FLAG) && !gGameExternalOptions.fDisease))
 		{
 			++iter;
 			continue;
diff --git a/Utils/XML_Items.cpp b/Utils/XML_Items.cpp
index 93c369c4e..39b92f3f8 100644
--- a/Utils/XML_Items.cpp
+++ b/Utils/XML_Items.cpp
@@ -1620,13 +1620,13 @@ itemEndElementHandle(void *userData, const XML_Char *name)
 		{
 			pData->curElement == ELEMENT;
 			if (atol(pData->szCharData))
-				pData->curItem.usLimitedToSystem|= 1;
+				pData->curItem.usLimitedToSystem|= FOOD_SYSTEM_FLAG;
 		}
 		else if (strcmp(name, "DiseaseSystemExclusive") == 0)
 		{
 			pData->curElement == ELEMENT;
 			if (atol(pData->szCharData))
-			pData->curItem.usLimitedToSystem|= 2;
+			pData->curItem.usLimitedToSystem|= DISEASE_SYSTEM_FLAG;
 		}
 
 		--pData->maxReadDepth;