Hi Shizara, I think the reason is that once the seal is broken it is both open to 'air' contamination and also with handling to re-wrap no matter how careful you are, it is also highly at risk of cross contamination.

I often do exactly what you suggest there Shizara.

I will admit to being careful with Ham and Pork though. As a teen I suffered food poisoning, I've never forgotten the experience.

Why is it that you can buy a pack of say sliced ham and the shelf life stretches into a good period of time, yet, it says consume within X amount (usually a couple of days). Is there a reason for not being able to open the packet and wrap smaller quantities in either cling film or put into a freezer bag and freeze? It encourages waste if one person can't eat the product within the specified time.