Weet bix went funny before expiry date

<p>Im currently pregnant and have the Bokomo weet bix for breakfast every morning. i visited the Waterloo Spar and purchased the smaller pack of weet bix at a special which was R18.99. i didnt think to check the expiry date, as it was still valid anyways. ie 05/10/17. however the taste of the bokomo weet bix tasted like it was already passed the expiry date as it has an old taste to it. its lying in the cupboard as clearly its not safe to eat at the moment. how can a product already taste funny before it reaches the expiry date?? i cannot go to the store as the date on the packaging is still valid.</p>