diff --git a/src/ZfcRbac/Collector/RbacCollector.php b/src/ZfcRbac/Collector/RbacCollector.php
index a8ff2c7..ba8f728 100644
--- a/src/ZfcRbac/Collector/RbacCollector.php
+++ b/src/ZfcRbac/Collector/RbacCollector.php
@@ -29,6 +29,7 @@
 use ZendDeveloperTools\Collector\CollectorInterface;
 use ZfcRbac\Options\ModuleOptions;
 use ZfcRbac\Service\RoleService;
+use ZfcRbac\Exception\InvalidArgumentException;
 
 /**
  * RbacCollector
@@ -43,11 +44,6 @@ class RbacCollector implements CollectorInterface, Serializable
      */
     const PRIORITY = -100;
 
-    /**
-     * @var array
-     */
-    protected $collection = [];
-
     /**
      * @var array
      */
@@ -184,7 +180,6 @@ private function collectPermissions(RoleInterface $role)
         if (method_exists($role, 'getPermissions')) {
             $permissions = $role->getPermissions();
         } else {
-
             // Gather the permissions for the given role. We have to use reflection as
             // the RoleInterface does not have "getPermissions" method
             $reflectionProperty = new ReflectionProperty($role, 'permissions');
@@ -209,20 +204,19 @@ private function collectPermissions(RoleInterface $role)
      */
     public function getCollection()
     {
-        return $this->collection;
+        return [
+            'guards'      => $this->collectedGuards,
+            'roles'       => $this->collectedRoles,
+            'permissions' => $this->collectedPermissions,
+            'options'     => $this->collectedOptions
+        ];
     }
-
     /**
      * {@inheritDoc}
      */
     public function serialize()
     {
-        return serialize([
-            'guards'      => $this->collectedGuards,
-            'roles'       => $this->collectedRoles,
-            'permissions' => $this->collectedPermissions,
-            'options'     => $this->collectedOptions
-        ]);
+        return serialize($this->getCollection());
     }
 
     /**
@@ -230,6 +224,14 @@ public function serialize()
      */
     public function unserialize($serialized)
     {
-        $this->collection = unserialize($serialized);
+        $collection = unserialize($serialized);
+        if (!is_array($collection)) {
+            throw new InvalidArgumentException(__METHOD__ . ": Unserialized data should be an array.");
+        }
+        $this->collectedGuards = $collection['guards'];
+        $this->collectedRoles  = $collection['roles'];
+        $this->collectedPermissions =  $collection['permissions'];
+        $this->collectedOptions = $collection['options'];
+
     }
 }
diff --git a/tests/ZfcRbacTest/Collector/RbacCollectorTest.php b/tests/ZfcRbacTest/Collector/RbacCollectorTest.php
index ae0c99c..47aa5b2 100644
--- a/tests/ZfcRbacTest/Collector/RbacCollectorTest.php
+++ b/tests/ZfcRbacTest/Collector/RbacCollectorTest.php
@@ -65,6 +65,7 @@ public function testUnserialize()
         $unserialized = [
             'guards'      => ['foo' => 'bar'],
             'roles'       => ['foo' => 'bar'],
+            'permissions' => ['foo' => 'bar'],
             'options'     => ['foo' => 'bar']
         ];
         $serialized   = serialize($unserialized);
@@ -77,8 +78,21 @@ public function testUnserialize()
         $this->assertSame(['foo' => 'bar'], $collection['guards']);
         $this->assertSame(['foo' => 'bar'], $collection['roles']);
         $this->assertSame(['foo' => 'bar'], $collection['options']);
+        $this->assertSame(['foo' => 'bar'], $collection['permissions']);
     }
 
+    public function testUnserializeThrowsInvalidArgumentException()
+    {
+        $this->setExpectedException('ZfcRbac\Exception\InvalidArgumentException');
+        $collector    = new RbacCollector();
+        $unserialized = 'not_an_array';
+        $serialized   = serialize($unserialized);
+
+        $collector->unserialize($serialized);
+
+    }
+
+
     public function testCollectNothingIfNoApplicationIsSet()
     {
         $mvcEvent  = new MvcEvent();
@@ -250,9 +264,11 @@ private function collectPermissionsPropertyTestBase(RoleInterface $role)
 
         $roleProvider = $this->getMock('ZfcRbac\Role\RoleProviderInterface');
 
-        $roleService = new RoleService($identityProvider,
+        $roleService = new RoleService(
+            $identityProvider,
             $roleProvider,
-            new RecursiveRoleIteratorStrategy());
+            new RecursiveRoleIteratorStrategy()
+        );
 
         $serviceManager->expects($this->at(0))
             ->method('get')
@@ -270,5 +286,4 @@ private function collectPermissionsPropertyTestBase(RoleInterface $role)
         $collector->unserialize($collector->serialize());
         return $collector->getCollection();
     }
-
-}
\ No newline at end of file
+}