High hydrostatic pressure has potential to eliminate pathogens in low-acid juices, says review

More research is needed to determine if high hydrostatic pressure (HHP) treatment can eliminate food pathogens in low-acid juices, according to a scientific review.

Mutlu Pilavtepe-Çelik, from the Food Technology Department, Vocational School of Ihsaniye, Kocaeli University, Kartepe, Kocaeli, Turkey looked at the role of High hydrostatic pressure (HHP) inactivation of foodborne pathogens in low-acid juices.

Publishing the findings in the International Journal of Food Science and Technology, she said the inactivation of foodborne pathogens in low-acid foods by HHP is “most urgent and critical”.

Pilavtepe-Çelik also called for more research in order to satisfy consumer demands for fresh-tasting products while retaining safety.

HHP processing

She found that there is more research on nutritional and sensory quality of HHP-treated low-acid juices, than the inactivation of foodborne pathogens by HHP (especially in vegetable juices).

HHP is well established in terms of enhancing food safety through its preservation ability, with it being used in products that are low pH fruit juices (grapefruit juice, mandarin juice and apple and orange juice), jams, jellies, fruit dressing, avocado and yoghurt.

The paper aims to give a thorough overview of the most recent findings specifically on how HHP treatments are used for the inactivation of foodborne pathogens in low-acid fruit and vegetable juices and the possible impacts of HHP on quality parameters of low-acid juices.

Consumption of unpasteurised fruit/vegetable juices has increased in recent years due to their freshness, low calorie contribution and good nutritional quality.

“However, unpasteurised fresh juices with low acidity (pH > 4.6) and high water activity (aw > 0.85) can support the growth of pathogens. Hence, pasteurisation is a necessary process in the production of low-acid juices,” she said.

Foodborne outbreaks traced to fresh produce and juices include a 2011 outbreak in cantaloupe which led to 146 cases and 30 deaths in 28 states, according to the US Center for Disease Control and Prevention (CDC).

HHP benefits

HHP treatment is considered an alternative to thermal pasteurisation as it can secure the freshness, nutritional value and organoleptic properties of low-acid juices.

The treatment has limited effect on the covalent bonds of low-molecular-mass compounds such as colour, flavour compounds and vitamins.

This means more research should be performed in low-acid juices in order to satisfy consumer demands for fresh-tasting products while retaining safety, she concluded.