Pemberton & Whitefoord created the new-look packaging, which is being rolling out across Starbucks' 535 UK stores.
A source said Starbucks is seeking to turn around perceptions of its food, as customers frequently accompany their coffee with sandwiches from retailers they perceive to be food specialists, such as Marks & Spencer.
The redesigned packaging, which features handwritten typography and is compostable and biodegradable, emphasises that it uses locally sourced products.
Starbucks has also announced an extensive growth plan for the UK. It plans to open coffee shops in London, where it already has more than 150 outlets within a five-mile radius, at a rate of one a fortnight for the next decade.
In November, the firm introduced a pre-payment card aimed at building customer loyalty. Card-holders can store between £2 and £150 on their cards.
The first Starbucks opened in the US in the 70s and the firm entered Europe in May 1998 through the acquisition of 65 Seattle Coffee Company stores in the UK.
Starbucks is the market-leading branded coffee-shop chain. It had a 19% share of consumer visits over a three-month period in 2006, according to Gfk NOP/Mintel, while Costa had a 17% share, Caffe Nero 9% and Coffee Republic 2%.
The market continues to perform well: sales through branded coffee shops rose 11% in 2006 to reach £675m, according to Mintel, and sales are predicted to grow 52% to a value of £1.02bn by 2010.