Read Work item header table SWWWIHEAD

I have a batch job which will be  scheduled in batch.

suppose it is executed at 1st hour.

let say when 1st executed ,50 work items are created by this single run.

I want to read those 50 work item id from table SWWWIHEAD, which are created in this single run.After reading i will send email to user with list of those 50 work items.

Please note, when job will be executed another hour, another 50 work items will be created by this job.Now i dont want to read 50+50 work items but i only want to read those newly created 50 work items.

Please guide me , how to do that.