Iterate an object in a generic method

Question

I have a generic method where <T> is defined as a certain type when a call to the method is made, the type that is passed is a custom object that incorporates the IEnumerable and IEnumerator interfaces and these work normally when iterating using foreach.  When I attempt to iterate that object in the generic method is doesn't allow me and gives me this message >> "foreach statement cannot operate on variables of type 'T' because 'T' does not contain a public definition for 'GetEnumerator'". Note the reason for this method being generic is to cater for different RiskRecord structures.

Here is my code:

 //Code to call the generic methods for the different structures are:
 1) GenericSummaryResultComparison<PC.RiskRecord>(szRiskRecordFilePath1, szRiskRecordSchemaFilePath);
 2) GenericSummaryResultComparison<GV.RiskRecord>(szRiskRecordFilePath1, szRiskRecordSchemaFilePath);
 3) GenericSummaryResultComparison<GV.RiskRecord>(szRiskRecordFilePath1, szRiskRecordSchemaFilePath);

 //Generic method
        private bool GenericSummaryResultComparison<T>(string szRiskRecordFilePath, string szRiskRecordSchemaFilePath) where T : class
        {
            try
            {
                T oRiskRecord;

                //Read in the risk files.
                oRiskRecord = SerializationMethods.DeserializeIt<T>(szResultFilePath1, szRiskRecordSchemaFilePath);

                foreach (T o in oRiskRecord)
                {
                    // actions
                }

                return true;
            }
            catch (Exception ex)
            {
                throw new ArgumentException(ex.Message, ex.InnerException);
            }
        }

How can I get the foreach to work for type T?

Thanks