Twitter guidelines from Advertising Age® that may apply to your bakery:
Track Tweets: You can't manage what you can't count, so use indicative product names (i.e. Tweety Pie) to track Twitter promotions with your POS system.
Sell before staling: Immediacy is Twitter's major strength. Use it to spark a sale at the end of day or before product gets stale.
Tweet when on the go: Alert your customers to your current and future whereabouts, especially for any off-site promotions or events.
Create conversation: Don't incessantly blast promotions, intersperse topical comments, pearls of wisdom and personalizing thoughts.