Long Integers are converting to scientific notation - ColdFusion

I am trying to pass a struct through a function, but the integers in it are converting to scientific notation.

Before deSerialization :

{"businessUnitValidList":2003051509034372557922
  , "shortMessage":"Success"
  , "longMessage":"Request Completed Successfully."
  , "status":20001
} 

After deSerialization:

 businessUnitValidList  2.00305150903E+021 

I have tried converting it into a string but it still gives me the same output. Any ideas?

Note: If I have more than one value in my businessUnitValidList, the numbers show up the way they are supposed to.

EDIT

This is the current code iteration:

<cfloop array="#businessUnitArray#" index="i">

   <cfquery name="validatebusinessUnit" datasource="dbproduction">
       select doctorid from survey.dbo.clientLocationMap
       where clientbrandid = '#arguments.clientBrandid#'
       and clientLocation = '#i#'
   </cfquery>

   <cfif validatebusinessUnit.recordcount gt 0>
       <cfset businessUnitValidList = listAppend(businessUnitValidList,toString(validatebusinessUnit.doctorid),",")>
   <cfelse>
       <cfset businessUnitInValidList = listAppend(businessUnitInValidList,i,",")>
   </cfif>

</cfloop>

<cfif businessUnitInValidList neq ''>
    <cfset ResponseStruct['BusinessUnitCodes']['businessUnitMixResponse']['businessUnitInValidList'] = "#businessUnitInValidList#">
    <cfset ResponseStruct['BusinessUnitCodes']['businessUnitMixResponse']['businessUnitValidList'] = "#businessUnitValidList#">
    <cfreturn serializeJSON(ResponseStruct['BusinessUnitCodes']['businessUnitMixResponse'])>
<cfelse>
    <cfset ResponseStruct['BusinessUnitCodes']['businessUnitSuccess']['businessUnitValidList'] = "#businessUnitValidList#">
    <cfreturn serializeJSON(ResponseStruct['BusinessUnitCodes']['businessUnitSuccess'])>
</cfif>