The twitter account should be open to all in the Abbotsford Biscuits organisation. Anyone should be allowed to tweet on behalf of the company. This is important because the aim is to share the company culture and values, so that you can build a following. The reality of any culture is that it is the amalgam of all viewpoints. If the brand twitter account is just maned by one person, then the personality will be too singular to truly display the organisations values. It also adds variety to the output and creates more interest with followers.
The team should be given a set of guidelines and then allowed to tweet as they please. This will also help with frequency of output, without impacting the general responsibility of staff and workers. They can do it on their breaks, or any time in or out of the office. The chaos of this proposed situation must be embraced or it simply wont work. For a true social media engagement control must be relinquished. The voice must be human, overtly honest and omnidirectional.