Oregano-cranberry mix cuts deadly Listeria bacteria
anti-microbial agent for food processors under constant pressure to
reduce the risk of foodborne diseases in the ever-expanding food
Scientists from the department of food science at the University of Massachusetts in the US say that cranberry and oregano extracts combined with lactic acid may inhibit the growth of the deadly food pathogen Listeria monocytogenes in meat and fish, a hardy bacterium capable of growing in refrigerated temperatures making it very difficult to control.
"Oregano and cranberry, useful botanicals generally regarded as safe for food flavouring and as functional ingredients are known for their antimicrobial activity linked to the phenolic moiety [specific segment of a molecule] and therefore are suitable as antimicrobial natural extracts when effectively combined with lactic acid," said the researchers.
The food protection market is currently enjoying decent growth because shelf life longevity and preservation are key concerns for food and beverage manufacturers operating into today's increasingly 'convenient' food culture.
Market analysts Global Information pitch the global food preservative market at $517.9 billion (€422.7 billion) reaching $634.3 billion by 2008 thanks to a buoyant annual growth rate of 4.1 per cent. In the US, growth in food preservatives will push 5.5 per cent rising to $257.7 billion in 2008 from $196.8 billion last year.
And while chemically synthetic preservatives are viewed with some suspicion by consumers, 'natural' chemical preservatives, such as the oregano-cranberry mix, are growing in both stature and respect.
Recent studies have highlighted the very high concentrations of antioxidants (i.e. greater than 75 mmol/100 g) of the popular herb oregano and food processors have already started to use oregano-based products, notably those designed to be stable at high temperatures, to preserve a range of food products.
For this latest study the scientists said that antimicrobial activity increased when oregano and cranberry extracts were mixed at a ratio of 75 per cent oregano and 25 per cent cranberry (wt/wt) with 0.1 mg of phenolic per disk or ml.
"The efficacy was further enhanced by lactic acid," they add, reporting their findings in the September issue of Applied and Environmental Microbiology, (5672-5678, Vol. 70, No. 9).
According to their research, the inhibition by 'phytochemical and lactic acid synergies' was most effective when beef and fish slices were stored at 4°C.