Hyperbaric storage at room temperature: Effect of pressure level and storage time on the natural microbiota of strawberry juice

Abstract

Abstract Hyperbaric storage at room temperature (HS-RT) has recently been proposed as a potential alternative to refrigeration for food preservation. However, there are still very few data about the effects of HS-RT conditions on food microbiota during and after storage. To estimate the effect of pressure level and storage time, we stored strawberry juices at 20 °C and 0.1, 25, 50, 100, and 200 MPa for 1, 10, or 15 days. Total aerobic mesophiles, lactic acid bacteria, and yeasts and molds were quantified before and immediately after storage as well as after a 3-day recovery period at atmospheric pressure and at 20 °C. Both pressure level and storage time affected microbial growth during and after HS-RT. In strawberry juice, storage at 25 MPa retarded microbial growth, but total growth inhibition could not be guaranteed, especially for long storage times. Storage pressures of at least 50 MPa were needed to reduce the initial microbial load during storage. After HS-RT at 25 or 50 MPa, microorganisms could quickly recover their cell-proliferating capacity and, therefore, larger pressures are required to increase microbial stability after decompression. Industrial relevance Hyperbaric storage at room temperature (HS-RT) involves very low energy consumption and, therefore, it can provide an interesting opportunity to reduce energy costs during food storage in comparison with other preservation methods such as freezing or refrigeration. HS-RT could be employed in a wide variety of scenarios: food industry, ship or truck transport for long distances, school or hospital kitchens, restaurants, or even at home. Moreover, its application in developing countries, in which the continuous supply of electric energy is difficult, would be especially noteworthy. However, before industrial implementation, much more research is needed to clarify the effects of the storage conditions on the agents that cause food deterioration (mainly microorganisms and enzymes). The current study contributes to increasing this knowledge.