The company said it had made the move following consumer concerns about children's diets and "potential links to food intolerance".
The ban covers the common flavour enhancer MSG and 12 colourings, all of which are legally permitted.
These include Sunset Yellow (E110), Tartrazine (E102) and Quinoline Yellow (E104).
The latest ban brings the total number of colours banned by the Co-op to 21.
"The removal of MSG and these colours is in direct response to [consumer] concerns, even though we have had to de-list a number of products as a result," says Christine Clarke, head of Co-op brand.
As the functional food trend continues to soar, food and beverage manufacturers are increasingly on the hunt for natural colours - fuelling growth in the colouring foodstuffs market and outstripping the base line growth of the European colours market in general valued at €195 million in 2001.
The European colouring market is expected to experience a compound annual growth rate of only 1 per cent for the period 2001-2008. In contrast, the colouring foodstuffs market is currently experiencing growth of an estimated 10 per cent to 15 per cent, driven by consumer interest in natural products," says Frost and Sullivan analyst Lyndsey Greig.
In addition to the influence of the functional food trend, the shift from synthetic colours to natural equivalents is underpinned by consumer suspicions that all E-numbers are unhealthy.
"Colouring foodstuffs include fruit and vegetable juices, concentrates and dried, powdered extracts. They do not contain any carriers or additives, and may be listed as ingredients, rather than as food additives," adds Greig.
There are three main classes of colour in foods: natural colours, browning colours, which are produced during cooking and processing, and additives.
After reviewing 2800 own-label food and drink products, the firm reformulated 53 brands to replace the colours and MSG with natural alternatives where possible, the firm tells FoodNavigator.com.
Among the reformulated products are mushy and processed peas, which commonly use the well-known artificial colour Tartrazine (E102) and the less well-known Green S (E142).
The Co-op has replaced these with naturally-derived colourings.
All Co-op sausages no longer contain Carmines (E120) and Co-op chicken and mushroom pasta sauce now has no added MSG.
Numerous children's products have also been reformulated, including dolly mixtures and flying saucers, which contained Quinoline Yellow (E104), Cochineal (E120), and Indigo Carmine (E132).
When reformulation was not an option, the retailer opted to totally delist the product from its range. And so some 27 products are not longer available, including marrowfat peas where no acceptable alternative could be found for Green S (E142), and prawn cocktail shells, which contained Carminic acid.
In addition, pink and white marshmallows, canned strawberries in syrup and Chinese style spare ribs are now off the shelves.
The UK food retailer claims to be the first supermarket group to ban a range of commonly-used colours and MSG in all its own-label foods.