Expired product

I went to Shoprite Malvern to purchase a Nutriday 600g, only to find out when I walk outside the store that the product was expired on the 20th of January 2016 still it is on the shelves. I went straight back to the store to return the product the manager apologised for the incident and give me my money which was good, but the question is how many products that you might be having in the Store that are expired and some people who might be illiterate still buying just because of someone who is on your payroll but not doing their duties as supposed to?