retail adjusting entry question

[taxman]

Client owns a retail gift shop. Does not take physical inventory. Bookkeeper prepared profit and loss for the year which I will use to prepare tax return. I think it would be advisable to account for some inventory shrinkage, i.e. theft, spoilage, etc. Should I advise bookkeeper to make adjusting entry to account for some loss of inventory? I would suggest debit to Cost of Goods Sold and credit to Inventory. Any advice would be appreciated including where I can find industry standards for inventory shrinkage, etc.