Bacteria offer novel approach to vitamin fortification

The research, led by the Netherlands-based food science institute NIZO​, started in 2001 to investigate the production of healthy components in food as a result of bacterial activity.

It was known then that some bacteria manufactured vitamins for their health and growth.

The following years have seen groundbreaking findings, demonstrating that certain bacteria excrete substantial quantities of vitamins into their surroundings, often dairy-based food products.

Furthermore, the bacteria studied do not consume much of the vitamins produced, instead leaving traces for the consumer of the end-product.

Approaching the end of the four-year, EU-funded, NutraCells​ project, researchers are now in talks with food manufacturers interested in using the findings to radically change the fortification of dairy and fermented foods.

Long used to selecting strains for their starter cultures, the food firms are looking at new combinations based on their capacity for vitamin production.

"We have shown that the principle is possible. By selecting strains that are high producers of vitamins together with those that do not consume too much of the vitamin, manufacturers can enhance vitamin levels in their products naturally,"​ said Dr Jeroen Hugenholtz, principal scientist at NIZO and also scientific director of the Kluyver Centre for Genomics of Industrial Fermentation.

"They will be able to say that their products are rich in certain vitamins while still satisfying consumers' concerns for a natural product, without added ingredients. In this way, the whole image of dairy foods as completely natural can continue to be supported,"​ he told NutraIngredients.com.

The first application will be in the dairy area, believes Hugenholtz, but the research could also be beneficial to producers of other fermented foods.

Fermentation is widely used in foods consumed in the Far East while in Europe the process is key to traditional foods like sauerkraut or olives. It is also used in the increasingly popular milk alternatives based on soya or oats, which often contain added vitamins or minerals to bring nutrient levels up to milk.

Around 8 per cent of all food and drink launches last year were fortified with vitamins and minerals, according to Mintel. However some European governments remain highly cautious about the potential overconsumption of vitamins by the general public.

In August, Denmark prevented a range of Kelloggs' cereals products from entering the market because they were considered to contain levels of vitamins and minerals that could cause Danish consumers to exceed safe intake of the nutrients in their overall diet.

A proposed European Commission regulation on addition of vitamins and minerals to foodstuffs is likely to put restrictions in place across the region, making this new research all the more valuable.

In the last year, the NutraCells researchers have also looked at the engineering of bacteria as a means of stepping up their vitamin production.

Writing in the May issue of Applied Environmental Microbiology​ (pp3146-8), they describe how genes essential for folate biosynthesis in Lactococcus lactis​ were cloned and transferred to Lactobacillus gasseri​, changing it from a folate consumer to a folate producer.

The bioavailability of this folate was confirmed in an animal study, finding that it was able to compensate for folate deficiency in the diet.

This principle could be used to increase folate levels in many fermented foods, say the researchers, although its practical use by industry remains a long way off, given the current climate surrounding genetic modification.

NIZO's team has also studied multivitamin production in Lactococcus lactis​ using metabolic engineering to make the bacteria overproduce both folate and riboflavin.

"Novel foods, enriched through fermentation using these multivitamin-producing starters, could compensate the B-vitamin-deficiencies that are common even in highly developed countries,"​ writes the team in the April issue of Metabolic Engineering​ (pp109-15).