On your form, you have the person's name and a dropdown (combobox) next to it. On the combobox, you make the rowsource have two columns: the ID and the name of the item. Set the bound column property to column 1. Set the column widths to zero inches for column 1 and (say) two inches for column 2. Set the list width to the same width as column 2. This will make column 1 invisible (no item numbers will show because column 1 width was set to zero) and let people see only the item name (column 2) when they click on the dropdown.
When they choose an item name (column 2) from the dropdown, because the bound column is really column 1 (which is invisible), Access will store the item ID along with the person's name in your table.
Michigan Dept. of Environmental Quality, Air Quality Division