Interactions between inhibition factors on microbial stability of fruit-based systems

Area of Science:

• Food Science
• Microbiology
• Chemical Engineering

Background:

• Shelf-life extension is crucial for fruit-based systems.
• Understanding microbial behavior in response to preservatives and processing is essential.
• Saccharomyces cerevisiae is a common spoilage organism in food and beverages.

Purpose of the Study:

• To create shelf-life maps for peach-based systems.
• To evaluate the effectiveness of thermal treatments and benzoic acid on Saccharomyces cerevisiae.
• To investigate the interaction between water activity (aw), pH, benzoic acid, and thermal treatments on microbial stability.

Main Methods:

• Head space gas chromatography was used to measure metabolic CO2.
• Peach-based systems with varying aw, pH, and benzoic acid concentrations were prepared.
• Three different thermal treatments were applied to assess their efficacy against a multi-resistant Saccharomyces cerevisiae strain.

Main Results:

• Preservative effectiveness against Saccharomyces cerevisiae decreased with reduced water activity (aw).
• A slight synergistic action was observed between thermal treatment and benzoic acid, but less than expected.
• Water activity (aw) showed a different synergistic interaction with thermal treatment effectiveness compared to osmotolerant species.

Conclusions:

• Water activity is a critical factor influencing preservative efficacy in peach-based systems.
• The interaction between processing parameters and microbial response differs from that observed in osmotolerant species.
• Shelf-life maps can be developed by understanding these complex interactions for optimized food preservation.