Bacterial Treatment Gives Cooked Ham A 39 Day Shelf Life

Traditional cooked ham has a maximum shelf life of three to four weeks (21-28 days), including the time from processing to shoppers buying the sliced meat in a supermarket. Currently cooked ham has 55% of the UK cooked meat market, and to maintain and expand this market processors are looking at new technologies to extend shelf life and open up new European markets for pork products.

"Many dairy products such as cheeses and yoghurts and some fermented meat products already use lactic acid producing bacteria to protect and preserve their products, and we know these are acceptable to consumers in terms of taste", says Roisin Lagan from the College of Agriculture, Food & Rural Enterprise in Cookstown, County Tyrone, Northern Ireland. "We investigated the possibility of extending the shelf life of cooked and sliced ham by treating it with a protective culture of Lactobacillus sakei, a common lactic acid producing bacterium."

When the commercially cured and then Lactobacillus treated meat was tasted by an untrained panel of consumers it was rated as tastier, with a better texture and overall more acceptability than the same conventionally treated ham. Chemical studies showed that the bacteria treated ham was drier and slightly more acidic than the conventionally preserved version of the meat.

The food scientists then looked at the shelf life of the new product and found that the lactic acid bacteria culture helped to prevent other types of bacteria from growing on the treated ham, protecting it from possible contamination by food poisoning bacteria or ones which would taint it by destroying its flavour and texture.

"This means that we have found a reliable and cost effective way of developing a tasty ham product with a maximum shelf life of 39 days when stored at 4 C" says Roisin Lagan. "This in turn will allow processors to have longer production runs leading to less wastage, thus reducing the environmental impact of storing and processing food waste. The increased shelf life will allow UK companies to compete more effectively on a global scale. Consumers will be assured a reliable, safe cooked ham product."

Dr Lagan is presenting the poster "Shelf life extension of cooked ham using a bioprotective culture"  on 04 September 2007 in the Plenary session of the 161st Meeting of the Society for General Microbiology at the University of Edinburgh, 03 - 06 September 2007.