Category Archives: HPP

Research – High-pressure processing: food safety without compromising quality

Posted on March 9, 2022 by | Leave a comment

EFSA

High-pressure processing (HPP) of food is effective at destroying harmful microorganisms and poses no more food safety concerns than other treatments. These are two of the conclusions of a scientific opinion published by EFSA today.

EFSA experts assessed the safety and efficacy of HPP of food and, more specifically, whether it can be used to control Listeria monocytogenes in ready-to-eat (RTE) foods and as an alternative to thermal pasteurisation of raw milk.

HPP is a non-thermal food preservation technique that kills microorganisms that can cause diseases or spoil food. It uses intense pressure for a certain time and has minimal effects on taste, texture, appearance, or nutritional values.

HPP can be used at different steps of the food chain, usually on pre-packed products. It can be applied to raw materials such as milk, fruit juices, and smoothies but also to products that have already been processed, such as sliced cooked meat products and RTE meals. In the latter case, it reduces the contamination originating from the manufacturing environment, for example during slicing and manipulation of the products.

This processing method reduces levels of Listeria monocytogenes in RTE meat products, at specific time-pressure combinations defined in the scientific opinion. In general, the longer the duration and intensity of the pressure, the more reduction is achieved. This is an important finding because L. monocytogenes contamination of RTE foods is a public health concern in the EU. HPP also proved to be effective at decreasing the levels of other pathogens, such as Salmonella and E. coli.

For raw milk, experts identified the time-pressure combinations that can be considered to have the same effect as thermal pasteurisation. These vary depending on the pathogen considered.

HPP is not specifically regulated at EU level and EFSA’s advice will inform the possible decisions of risk managers in this field.

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Posted in Decontamination Microbial, EFSA, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Safety, food safety training, Food Technology, HPP, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microorganism DNA, Technology

Research – High-Pressure-Induced Sublethal Injuries of Food Pathogens—Microscopic Assessment

Posted on December 5, 2021 by | Leave a comment

MDPI

High Hydrostatic Pressure (HHP) technology is considered an alternative method of food preservation. Nevertheless, the current dogma is that HHP might be insufficient to preserve food lastingly against some pathogens. Incompletely damaged cells can resuscitate under favorable conditions, and they may proliferate in food during storage. This study was undertaken to characterize the extent of sublethal injuries induced by HHP (300–500 MPa) on Escherichia coli and Listeria innocua strains. The morphological changes were evaluated using microscopy methods such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Epifluorescence Microscopy (EFM). The overall assessment of the physiological state of tested bacteria through TEM and SEM showed that the action of pressure on the structure of the bacterial membrane was almost minor or unnoticeable, beyond the L. innocua wild-type strain. However, alterations were observed in subcellular structures such as the cytoplasm and nucleoid for both L. innocua and E. coli strains. More significant changes after the HHP of internal structures were reported in the case of wild-type strains isolated from raw juice. Extreme condensation of the cytoplasm was observed, while the outline of cells was intact. The percentage ratio between alive and injured cells in the population was assessed by fluorescent microscopy. The results of HHP-treated samples showed a heterogeneous population, and red cell aggregates were observed. The percentage ratio of live and dead cells (L/D) in the L. innocua collection strain population was higher than in the case of the wild-type strain (69%/31% and 55%/45%, respectively). In turn, E. coli populations were characterized with a similar L/D ratio. Half of the cells in the populations were distinguished as visibly fluorescing red. The results obtained in this study confirmed sublethal HHP reaction on pathogens cells. View Full-Text

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Posted in E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, HPP, Listeria, Listeria innocua, microbial contamination, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Research, Technology

Research – Inactivation of Foodborne Viruses by High-Pressure Processing (HPP)

Posted on January 23, 2021 by | Leave a comment

MDPI

Rotavirus

High-pressure processing (HPP) is an innovative non-thermal food preservation method. HPP can inactivate microorganisms, including viruses, with minimal influence on the physicochemical and sensory properties of foods. The most significant foodborne viruses are human norovirus (HuNoV), hepatitis A virus (HAV), human rotavirus (HRV), hepatitis E virus (HEV), human astrovirus (HAstV), human adenovirus (HuAdV), Aichi virus (AiV), sapovirus (SaV), and enterovirus (EV), which have also been implicated in foodborne outbreaks in various countries. The HPP inactivation of foodborne viruses in foods depends on high-pressure processing parameters (pressure, temperature, and duration time) or non-processing parameters such as virus type, food matrix, water activity (aw), and the pH of foods. HPP was found to be effective for the inactivation of foodborne viruses such as HuNoV, HAV, HAstV, and HuAdV in foods. HPP treatments have been found to be effective at eliminating foodborne viruses in high-risk foods such as shellfish and vegetables. The present work reviews the published data on the effect of HPP processing on foodborne viruses in laboratory media and foods. View Full-Text

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Posted in food contamination, Food Hazard, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Pathogen, Food Safety, Food Testing, Food Virus, Hepatitis A, Hepatitis E, HPP, Virus