The guide covers all aspects of stock valuation to ensure "a more professional, low-risk approach", according to the ILTSA.
Topics covered include what the purchaser is obliged to pay, how stock near to the end of its shelf life should be treated and how to check that it is is in good condition.
It also covers methods of valuation for all items sold over and above the price paid for the business, such as glassware and cleaning materials.
A spokesman for the ILTSA said: "A change in the way that stock valuations are carried out at changeovers has long been overdue.
"The already stressful process of buying and selling a licensed trade outlet has often been made worse by misunderstandings and heated discussions with regard to the sale and purchase of the stock on the day of the change."
The ILTSA will issue all parties concerned with the guidelines before the changeover to ensure a smooth valuation without any last minute debate or misunderstanding.
"Most importantly, the agreement of both parties to accept a valuation carried out on these terms protects both sides and ensures mutual benefit to both parties on the day," the spokesman added.