A combination of sonication and osmotic evaporation represents a promising new technology that could be designed to athermally produce safe, concentrated fruit juices, claims a new study.
The results derived from the research were published in the Journal of Food Safety and indicate that combining sonication with osmotic pressure during storage of concentrated orange juice provides a way of achieving a 5 log reduction of Salmonella spp.
The authors have termed the technology designed to athermally process fruit juices as ‘osmosonication’, and claim that besides the nutritional and sensory benefits provided by athermal processes, final products would also be safe for the consumer.
Desire for natural
Consumers are increasingly seeking natural products that have been minimally processed in order to avoid destruction or partial removal of the health promoting substances present in fruits, according to the study.
However, the authors state that consumption of minimally processed fruit juices has increased the number of outbreaks of foodborne illnesses in recent years, with orange juice frequently identified as the vehicle of transmission in several of these outbreaks, many of them related to Salmonella species.
The authors said the aim of their research was to evaluate the effect of osmotic pressure alone, or combined with the application of sonication, on the reduction of Salmonella spp. in concentrated orange juice.
The researchers explained that an osmotic pressure of 12.6 MPa, low pH and a 24 hour storage period, when combined, appear to significantly reduce the Salmonella population in the juice by almost 2.7 log cfu/mL.
“However, the 5 log reduction goal normally targeted by food industries was not achieved and therefore additional treatments, alone or combined, must be implemented to guarantee food safety of the athermally processed juice,” said the scientists.
The researchers said that, in contrast, sonication combined with an increase in osmotic pressure strongly affects the survival of Samonella spp. in orange juice after at least 24 hours of storage.
“By quickly concentrating a juice to reach the osmotic pressure of 12.6 MPa, while applying sonication for one hour, a 5 log cfu/mL reduction of Salmonella spp. can be reached between 24 and 168 hours of storage, which is a promising result,” claim the authors.
The researchers said that based on the positive results of their study there is a need to design equipment and optimise operating parameters including in-line sonication times and flow rates in order to advance this new technology.
Source: Journal of Food SafetyPublished Online ahead of print DOI: 10.1111/j.1745-4565.2008.00127.xCombined effect of osmotic pressure and sonication on the reduction of Salmonella Spp in concentrated orange juice uthors: E. Wong, A.M. Pérez, F. Vaillant