Effect of combined methods of preservation on the naturally occurring microflora of avocado purée

The effects of combining techniques such as addition of sorbic acid, modification of water activity (aw), reduction of pH, modification of the packaging atmosphere and control of the storage temperature on the microbiological shelf life of avocado purée were evaluated during four months of storage. Results show that the addition of 300 mg/kg of sorbic acid can extend the stability of the product native microflora for storage periods of up to four months. Vacuum packaging as well as storage at 4 °C was also found to have a significant influence over the control of yeast and mould populations and could preserve avocado purées during 112 days without addition of antimicrobial. The addition of maltose to reduce aw to 0.96 resulted in slightly more stable purées but would impart important changes to the product palatability.