Detection of Hepatitis E Virus in the Pig Livers and Retail Pork Samples Collected in Selected Cities in China.

Hepatitis E virus (HEV) is a biological hazard that must be controlled and is a recognized etiological agent in viral hepatitis. This is a zoonotic virus and can be transmitted through the fecal-oral route. The pig is an important reservoir host of HEV, and is a source of contamination for the consumer after the consumption of raw or undercooked pork products. When detected, the most prevalent genotype of HEV in China is genotype 4 (denoted as HEV-4). To ensure the safety of this food of animal origin, we undertook a survey of HEV contamination in pig livers and pork samples available for sale, in retail outlets in selected cities in China. Viral RNA was purified from samples collected by lysing in Trizol followed by purification using trichloromethane and virus RNA extract kit. An additional step was applied to improve the recovery rate by adding RNase OUT when extracting virus RNA from pig livers, and the RNA productions were washed in 75% (v/v) ethanol to remove inhibitors. In total, 158 pig livers and 80 pork samples were procured and analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). After purification of total RNA from all samples taken and analyzed by RT-qPCR, a single pig liver was positive by this method for HEV. The positive rate was calculated as 0.63%. In this study, a single positive sample was detected. Considering the dietary habits of Chinese people, pork is a popular food that on occasion may be contaminated with HEV, thereby posing a threat to consumer health. Ongoing surveillance is required to assess the risk to human health arising from HEV-contaminated pork being offered for sale, at retail outlets, especially in the areas of China where pig production is practiced.

High Predictive Power of Meat Juice Serology on the Presence of Hepatitis E Virus in Slaughter Pigs.

Hepatitis E virus (HEV) as a zoonotic agent can be responsible for an acute hepatitis in humans, which is usually self-limiting. Progression toward a chronic stage is possible, especially in immunocompromised patients. In the past decade, the number of hepatitis E cases in humans in Germany has increased enormously to 3491 cases in 2018. Domestic pigs have been identified as a main animal reservoir and the consumption of raw and undercooked pork products, that is, livers or liver products, meat or meat products, is known as a potential risk of foodborne HEV infection. The aim of this study was to determine whether serological tests are appropriate to predict the occurrence of HEV in the liver and muscle of domestic pigs in Germany. In 2018, samples of meat juice, liver, and ham muscle were collected from 250 fattening pigs at an abattoir in North West Germany. Samples were analyzed for the presence of HEV antibodies using enzyme-linked immunosorbent assay respectively for the presence of HEV RNA using real-time reverse transcription-polymerase chain reaction. In total, 62% (155/250) of the meat juice samples were positive for HEV antibodies at a single animal basis. At herd level, 72% (18/25) of the herds were seropositive. The HEV prevalence in the liver was 17.2% (43/250). Each positive liver sample originated from seropositive herds respectively from HEV seropositive pigs. This study demonstrates for the first time the significant correlation between a positive HEV serology and the occurrence of HEV RNA in the liver of slaughter pigs (χ2 = 31.83; p < 0.001), highlighting the significant predictive power of positive serological results on the occurrence of HEV RNA in the liver.

Risk factors for hepatitis E virus seropositivity in Dutch blood donors.

BACKGROUND: A marked increase of hepatitis E cases has recently been observed in the Netherlands. Causes of the (re-)emergence of hepatitis E virus (HEV) and exact sources and routes of transmission of HEV infection are currently unknown. We aimed to identify risk factors for HEV seropositivity. METHODS: Using the Wantai EIA, 2100 plasma samples of blood donors from all over the Netherlands aged 18-70 years were tested for anti-HEV IgG antibodies. A questionnaire on socio-demographic characteristics, health, and potential risk factors for HEV exposure was sent to these participants. RESULTS: The overall IgG-seroprevalence was 31% (648/2100) and increased with age. Several food products were independently associated with IgG-seropositivity in a multivariate analysis adjusting for age and gender among 1562 participants who completed the questionnaire: traditional Dutch dry raw sausages called "cervelaat", "fijnkost", "salami" and "salametti" which are generally made from raw pork and beef (aOR 1.5; 95%CI 1.2-1.9), frequent consumption of bovine steak (aOR 1.3; 95%CI 1.0-1.7), and frequent consumption of smoked beef (aOR 1.3 95%CI 1.0-1.7). Although not frequently reported, contact with contaminated water was also a risk factor for seropositivity (aOR 2.5; 95%CI 1.5-4.4). Lower seroprevalence was associated with eating raspberries, going out for dinner, and contact with wild animals and dogs. CONCLUSION: Several pork food products, mainly dry raw sausages, and contact with contaminated water were associated with past HEV infection in the Netherlands. Further investigation is needed into the prevalence and infectivity of HEV in these risk factor food products, as well as investigation of the production methods and possible origin of HEV-contamination within these sausages, e.g. very small amounts of pork liver, pig-derived blood products as food additive, or the pork muscle tissue.

Case-control study on risk factors for acute hepatitis E in Germany, 2012 to 2014.

BackgroundNotified cases of hepatitis E have increased 40-fold in the past 10 years in Germany. Food safety is a major concern as hepatitis E virus (HEV) RNA has been detected in ready-to-eat retail-level food products. The objective of this case-control study was to assess risk factors for autochthonous symptomatic hepatitis E and explore reasons for delays in diagnosis. Methods: Demographic, clinical and exposure data from notified hepatitis E cases and individually matched population controls were collected in semi-standardised telephone interviews. Conditional logistic regression analysis was used to calculate matched odds ratios (mOR) and population attributable fractions (PAF). Results: In total, 270 cases and 1,159 controls were included (mean age 53 years, 61% men in both groups). Associated with disease were: consumption of undercooked pork liver, pork, wild boar meat, frankfurters, liver sausage and raw vegetables; contact with waste water (occupational) and various host factors (mORs between 1.9 and 34.1, p value < 0.03). PAF for frankfurters and liver sausage were 17.6%, and 23.6%, respectively. There were statistically significant differences in the clinical presentation and hospitalisation proportion of acute hepatitis E in men and women. Diagnosis was preceded by more invasive procedures in 29.2% of patients, suggesting that hepatitis E was not immediately considered as a common differential diagnosis. Conclusions: Our study suggests that there are indeed sex-specific differences in disease development and lends important epidemiological evidence to specific ready-to-eat pork products as a major source for autochthonous hepatitis E. A review of existing consumer recommendations and production methods may be indicated.

Pork products associated with human infection caused by an emerging phylotype of hepatitis E virus in England and Wales.

Since 2010, human hepatitis E infections have increased in England and Wales. Most cases are locally acquired and caused by hepatitis E virus genotype 3 (HEV G3). HEV G3 is linked to the consumption of pork products. The increase is associated with the emergence of a new phylotype, HEV G3-group 2 (G3-2, also known as G3abcdhij). Sixty individuals with confirmed hepatitis E infection and no history of travel outside the UK were recruited: 19 were infected with HEV G3-group 1 (G3-1 or G3efg) and 41 with G3-2. Epidemiological data relating to usual shopping habits and consumption of ham and sausages were analysed together with typing data to identify any associations with HEV phylotype. Study participants who purchased ham and/or sausage from a major supermarket were more likely to have HEV G3-2 infection (Relative risks 1·85, P = 0·06, CI 0·97-3·53). The HEV G3-2 phylotype has not been detected in indigenous UK pigs and it is suggested that human infections could be the result of consumption of products made from pork originating outside the UK. This does not infer blame on the supermarket but the epidemiology of HEV is dynamic and reflects complex animal husbandry practices which need to be explored further.

Hepatitis E: the current state of play.

The hepatitis E virus (HEV) is a major cause of acute hepatitis globally. Genotypes 1 and 2 (G1 and G2) are obligate human pathogens transmitted faeco-orally, leading to epidemics in developing countries. In contrast, genotypes 3 and 4 (G3 and G4) have a wider host range, including humans, but are primarily porcine viruses and are transmitted from animals to humans as a food-borne zoonosis when meat from an infected animal is consumed. HEV is increasingly recognised as a problem in developed countries, including countries in Europe. G3 HEV is now the most common cause of acute viral hepatitis in the UK and cases continue to rise. The majority of these infections are acquired within the UK and thought to be from insufficiently cooked meat, predominantly processed pork meat. Previously thought to only cause self-limiting disease, HEV infection can persist in immunosuppressed patients, which may lead to chronic hepatitis and the rapid development of cirrhosis. Of particular interest to the transfusion community has been the possibility of transfusion-transmitted HEV, which has been reported from countries classically considered HEV-endemic but also non-endemic countries in Europe and Japan. This has prompted some countries to introduce screening for HEV in blood donations.

Thermal Inactivation Kinetics of Human Norovirus Surrogates and Hepatitis A Virus in Turkey Deli Meat.

Human noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to the consumption of presliced ready-to-eat deli meats. The objectives of this research were to determine the thermal inactivation kinetics of HNoV surrogates (murine norovirus 1 [MNV-1] and feline calicivirus strain F9 [FCV-F9]) and HAV in turkey deli meat, compare first-order and Weibull models to describe the data, and calculate Arrhenius activation energy values for each model. The D (decimal reduction time) values in the temperature range of 50 to 72°C calculated from the first-order model were 0.1 ± 0.0 to 9.9 ± 3.9 min for FCV-F9, 0.2 ± 0.0 to 21.0 ± 0.8 min for MNV-1, and 1.0 ± 0.1 to 42.0 ± 5.6 min for HAV. Using the Weibull model, the tD = 1 (time to destroy 1 log) values for FCV-F9, MNV-1, and HAV at the same temperatures ranged from 0.1 ± 0.0 to 11.9 ± 5.1 min, from 0.3 ± 0.1 to 17.8 ± 1.8 min, and from 0.6 ± 0.3 to 25.9 ± 3.7 min, respectively. The z (thermal resistance) values for FCV-F9, MNV-1, and HAV were 11.3 ± 2.1°C, 11.0 ± 1.6°C, and 13.4 ± 2.6°C, respectively, using the Weibull model. The z values using the first-order model were 11.9 ± 1.0°C, 10.9 ± 1.3°C, and 12.8 ± 1.7°C for FCV-F9, MNV-1, and HAV, respectively. For the Weibull model, estimated activation energies for FCV-F9, MNV-1, and HAV were 214 ± 28, 242 ± 36, and 154 ± 19 kJ/mole, respectively, while the calculated activation energies for the first-order model were 181 ± 16, 196 ± 5, and 167 ± 9 kJ/mole, respectively. Precise information on the thermal inactivation of HNoV surrogates and HAV in turkey deli meat was generated. This provided calculations of parameters for more-reliable thermal processes to inactivate viruses in contaminated presliced ready-to-eat deli meats and thus to reduce the risk of foodborne illness outbreaks.

Pork consumption and seroprevalence of hepatitis E virus,Thailand, 2007-2008.

The nationwide seroprevalence of hepatitis E IgG was determined among young men in Thailand. Overall seroprevalence was 14% (95% CI 13%-15%); range by province was 3%-26%. Seroprevalence was lowest in the south, an area predominantly occupied by persons of the Islam religion, whose dietary laws proscribe pork.

Hepatitis E virus in England and Wales: indigenous infection is associated with the consumption of processed pork products.

Indigenously acquired hepatitis E infections have increased substantially in England and Wales since 2010. Epidemiological investigations were undertaken to determine risk factors for the acquisition of infection. A case-control study (25 cases, 75 controls) was used to test the hypothesis that hepatitis E infection was related to consumption of pork products. In a multivariable model, consumption of pork pie [odds ratio (OR) 6·33, 95% confidence interval (CI) 1·41-28·48, P = 0·009] and consumption of ham and sausages purchased from a major UK supermarket chain (OR 10·12, 95% CI 1·68-60·81, P = 0·023) were significantly associated with indigenous infection. The consumption of sausages and ham purchased from the supermarket was highly correlated; however. separate models showed that each variable was significantly associated with infection (OR 7·59, 95% CI 1·81-31·84, P = 0·004 and OR 10·98, 95% CI 1·84-65·35, P = 0·003, respectively). Although contamination of sausages with HEV has previously been shown this study also raises concerns about other processed pork products and whether current practice in preparing these products is sufficient to prevent transmission of HEV.

Isolation and phylogenetic analysis of avian infectious bronchitis virus from an imported chicken meat product in Malaysia.

Avian infectious bronchitis (IB), a Gammacoronavirus, is a highly contagious upper respiratory disease, affecting chickens of all ages with a significant economic threat to the poultry industry. In February 2020, a specimen of imported chicken meat product was received and requested for coronavirus testing. The result was positive for the avian coronavirus, the IB virus (IBV) by molecular detection in the pre-screening test. Thus, this study aimed to isolate and characterize the IBV from the specimen. Virus isolation via egg inoculation was attempted and IBV was successfully isolated. The S1 subunit of the spike (S) gene of the IBV was amplified, sequenced, and the Basic Local Alignment Search Tool (BLAST) analysis showed that the IBV has 99% and 98% nucleotide similarity with the Malaysian and China IBVs, respectively. The phylogenetic analysis indicated that the virus belongs to the GI-19 lineage (also known as the QX strain) and is grouped with other IBVs from Malaysia and China. The GI-19 lineage is one of the primary IB strains that circulate in Malaysia. The recovery of the virus may be due to the persistence characteristic of the virus on meat; and the cold chain practices in the imported food product prolong the survival of this coronavirus. Though IBV is not identified as a hazard in chicken meat or meat products, raw food should be cooked thoroughly before being consumed. With the increase in international trade in poultry and poultry products, disease screening at the entry point and import risk analysis is crucial to ensure food safety and prevent the introduction of new viruses into Malaysia.

Hepatitis E virus in pork liver sausage, France.

We investigated viability of hepatitis E virus (HEV) identified in contaminated pork liver sausages obtained from France. HEV replication was demonstrated in 1 of 4 samples by using a 3-dimensional cell culture system. The risk for human infection with HEV by consumption of these sausages should be considered to be high.

Other aspects of BSE issues in East Asian countries.

Scientific risk estimates of BSE can be the same internationally; however, socioeconomic backgrounds, such as food supply (e.g., beef import status) and dietary life, are different between East Asian countries (i.e., in this article, Japan, Korea, and Taiwan) and Western countries, which may account for differences in risk perception of people. Since political and social backgrounds also differ among these East Asian countries, they will also influence people's attitudes toward food safety. Psychological factors such as "dread" and the "unknown" are considered to be important in risk perception, but socioeconomic, and in some cases political, situations (e.g., attitudes of politicians and political pressures in trade) may strongly influence the perception and acceptance of various risks by citizens. With regard to the BSE issues, latter aspects may contribute a lot to risk perception, but have not been examined in depth until now. Although protection of health is the key element to food safety, sometimes business factors can overwhelm safety issues in international trade. Appropriate risk governance in food safety issues, such as BSE, can be attained not only through application of outputs of scientific assessment, but also through deliberation of various aspects, that may have strong influence on people's risk perception, and improved communication among stakeholders and also among countries.

Consumption of bovine spongiform encephalopathy (BSE) contaminated beef and the risk of variant Creutzfeldt-Jakob disease.

To date, the variant Creutzfeldt-Jakob disease (vCJD) risk assessments that have been performed have primarily focused on predicting future vCJD cases in the United Kingdom, which underwent a bovine spongiform encephalopathy (BSE) epidemic between 1980 and 1996. Surveillance of potential BSE cases was also used to assess vCJD risk, especially in other BSE-prevalent EU countries. However, little is known about the vCJD risk for uninfected individuals who accidentally consume BSE-contaminated meat products in or imported from a country with prevalent BSE. In this article, taking into account the biological mechanism of abnormal prion PrP(res) aggregation in the brain, the probability of exposure, and the expected amount of ingested infectivity, we establish a stochastic mean exponential growth model of lifetime exposure through dietary intake. Given the findings that BSE agents behave similarly in humans and macaques, we obtained parameter estimates from experimental macaque data. We then estimated the accumulation of abnormal prions to assess lifetime risk of developing clinical signs of vCJD. Based on the observed number of vCJD cases and the estimated number of exposed individuals during the BSE epidemic period from 1980 to 1996 in the United Kingdom, an exposure threshold hypothesis is proposed. Given the age-specific risk of infection, the hypothesis explains the observations very well from an extreme-value distribution fitting of the estimated BSE infectivity exposure. The current BSE statistics in the United Kingdom are provided as an example.

Hepatitis E virus in pork food chain, United Kingdom, 2009-2010.

We investigated contamination by hepatitis E virus (HEV) in the pork production chain in the United Kingdom. We detected HEV in pig liver samples in a slaughterhouse, in surface samples from a processing plant, and in pork sausages and surface samples at point of sale. Our findings provide evidence for possible foodborne transmission of HEV during pork production.

Biosecurity aspects and pathogen inactivation in acidified high risk animal by-products.

The aim of the study was to investigate the effects of formic acid addition to ground high risk animal by-products (ABP 1) in terms of stabilization and pathogen inactivation and to evaluate the biosecurity risk connected with the ABP 1 based combustion fuel Biomal. Laboratory studies were performed on the persistence of Salmonella Typhimurium, Bacillus cereus spores, porcine herpes virus, avian influenza virus, bovine viral diarrhea virus, equine rhinitis A virus and porcine parvovirus in Biomal at different storage times. It was shown that Salmonella and enveloped viruses were inactivated within 1 day (24 h). Bacillus cereus spores were not reduced during 147 days and the non-enveloped virus porcine parvovirus was still detected after 168 days of storage. The conclusion that can be drawn from the study is that transmission of some highly contagious diseases such as foot-and-mouth-disease, swine vesicular disease and egg drop syndrome, caused by non-enveloped viruses, may follow accidental leakages of Biomal. In addition, there is a risk of transmission of the diseases anthrax and black leg, caused by sporulating bacteria.

An analysis of select swine feed ingredients and pork products imported into the United States from African swine fever virus affected countries.

The potential for feed ingredients to serve as a vehicle for African swine fever virus (ASFV) introduction to the United States remains a significant concern. It is therefore imperative that channels through which high-risk livestock feeds and feed ingredients are imported into the United States from ASFV-positive countries are identified and considered into the USDA's ASF National Response Framework. The purpose of this study is to demonstrate the use of a novel analytical tool to categorically quantify pork products and potential high-risk feed ingredients that have entered the United States from ASFV-positive countries over a 5-year period (2016-2020). Data for this study were obtained at the United States International Trade Commission Harmonized Tariff Schedule (HTS) website (www.hs.usitc.gov), a publicly available website that provides transaction information on specific trade commodities between the United States and its international trading partners. A total of 29 high-risk pork products or feed ingredients with the potential to be fed to pigs were analysed. High risk products and ingredients were defined as those that previous research has shown to facilitate extended viral survivability, and includes products such as soybean oilcake, distillers grains, pet food, and pork sausage casings. Data were exported into Microsoft Excel and organized into pivot tables to describe the quantity of each product by country of origin and Port of Entry (POE). The analysis focused on the 60 ASFV-positive countries as currently reported by the World Organization for Animal Health (OIE). In 2020, a total of 486,902 metric tons (MT) of these high-risk products were imported into the United States from a total of 19 of the 60 foreign countries currently listed as ASFV positive by the OIE. A majority of imported animal feed ingredients came from India in 2020 (85.8%; 392,243 MT), whereas the majority of pork products and by-products were imported from Poland (21,191 MT, 70.6%). Soybean oilcake from India entered the United States through a total of 15 ports of entry (POEs) in 2020. Of these POEs, a total of five POEs received greater than 91% of all of soy oilcake originating from India, including Baltimore, MD (37.7%); San Francisco, CA (30.1%); Seattle, WA (12.7%); New Orleans, LA (5.9%); and Detroit, MI (5.1%). When examining trends over a 5-year period, a few noteworthy findings include the dramatic rise in soybean oilcake imported from India when compared to China, and a dramatic decrease in the total volume of pork sausage casings imported from China into the United States. To support the risk management of feed imports, our novel approach focuses on seaport of highest risk and quantity of product received. Data provided in this report represent an initial listing of suspect pork products and feed ingredients entering the United States, much of which is destined for animal feed. Specific detailed examples are provided in order to demonstrate the tool's flexible interface, which can be quickly modified to zero-in on specific feed ingredients, countries, or POEs depending on what the user's question may be. To the authors' knowledge, the use of and application of such a tool has not been previously utilized to support ongoing risk mitigation efforts. Potential outlets for future use of the analytical tool will include a more user-friendly and interactive interface providing an inclusive analysis of global livestock feed ingredient sourcing.

Isolation and characterisation of a novel Podoviridae-phage infecting Weissella cibaria N 22 from Nham, a Thai fermented pork sausage.

A novel Podoviridae lactic acid bacteria (LAB) phage from Nham, a Thai fermented pork sausage, is reported. From a total of 36 samples, 41 isolates of LAB were obtained and employed as hosts for the isolation of phages. From these LAB, only one phage, designated Φ 22, was isolated. The lactic acid bacterial isolate named N 22, sensitive to phage Φ 22 infection was identified by an API 50 CHL kit and N 22's complete sequence of the 16S rDNA sequence. BLASTN analysis of the 16S rDNA sequence revealed a 99% similarity to the 16S rDNA sequence of Weissella cibaria in the GenBank database. Electron micrographs indicated that the phage head was icosahedral with head size and tail length of 92 × 50 nm and 27 nm, respectively. On the basis of the morphology, this phage belongs to the family Podoviridae. Host-range determination revealed that the phage Φ 22 was not capable of infecting the other 40 isolates of LAB and referenced Weissella strains used. A one-step growth experiment showed that the latent period and burst size were estimated at 110 min and 55 phage particles/infected cell, respectively. Furthermore, the phage was infective over a wide range of pH (pH 5.0-8.0) and the D time of Φ 22 was calculated as 88 s at 70 °C and 15s at 80 °C. Phage titers decreased below the detection limit (20 PFU/ml) after heating for more than 60s at 80 °C, or 20s at 90 °C or less than 10s at 100 °C. The results from the study of Nham revealed that Φ 22 was active against the potential starter culture (W. cibaria N 22) for Nham fermentation. Phage infection could adversely affect the fermentation process of Nham by delaying acidification when using W. cibaria N 22 as a starter. However, the results from a sensory test revealed that the panelists did not detect any defects in the final products. This is the first report on the isolation of W. cibaria phage.

Foodborne transmission of hepatitis A and hepatitis E viruses: A literature review.

Foodborne viruses have been recognized as a growing concern to the food industry and a serious public health problem. Hepatitis A virus (HAV) is responsible for the majority of viral outbreaks of food origin worldwide, while hepatitis E virus (HEV) has also been gaining prominence as a foodborne viral agent in the last years, due to its zoonotic transmission through the consumption of uncooked or undercooked infected meat or derivatives. However, there is a lack of scientific reports that gather all the updated information about HAV and HEV as foodborne viruses. A search of all scientific articles about HAV and HEV in food until March 2020 was carried out, using the keywords "HAV", "HEV", "foodborne", "outbreak" and "detection in food". Foodborne outbreaks due to HAV have been reported since 1956, mainly in the USA, and in Europe in recent years, where the number of outbreaks has been increasing throughout time, and nowadays it has become the continent with the highest foodborne HAV outbreak report. Investigation and detection of HAV in food is more recent, and the first detections were performed in the 1990s decade, most of them carried out on seafood, first, and frozen food, later. On the other hand, HEV has been mainly looked for and detected in food derived from reservoir animals, such as meat, sausages and pate of pigs and wild boars. For this virus, only isolated cases and small outbreaks of foodborne transmission have been recorded, most of them in industrialized countries, due to HEV genotype 3 or 4. Virus detection in food matrices requires special processing of the food matrix, followed by RNA detection by molecular techniques. For HAV, a real-time PCR has been agreed as the standard method for virus detection in food; in the case of HEV, a consensus assay for its detection in food has not been reached yet. Our investigation shows that there is still little data about HAV and HEV prevalence and frequency of contamination in food, prevalent viral strains, and sources of contamination, mainly in developing countries, where there is no research and legislation in this regard. Studies on these issues are needed to get a better understanding of foodborne viruses, their maintenance and their potential to cause diseases.

Stability of hepatitis E virus at high hydrostatic pressure processing.

Hepatitis E virus (HEV) is the causative agent of acute and chronic hepatitis in humans. The zoonotic HEV genotype 3 is the main genotype in Europe. The foodborne transmission via consumption of meat and meat products prepared from infected pigs or wild boars is considered the major transmission route of this genotype. High hydrostatic pressure processing (HPP) is a technique, which can be used for inactivation of pathogens in food. Here, preparations of a cell culture-adapted HEV genotype 3 strain in phosphate-buffered saline (PBS) were subjected to HPP and the remaining infectivity was titrated in cell culture by counting fluorescent foci of replicating virus. A gradual decrease in infectivity was found by application of 100 to 600 MPa for 2 min. At 20 °C, infectivity reduction of 0.5 log10 at 200 MPa and 1 log10 at 400 MPa were observed. Slightly higher infectivity reduction of 1 log10 at 200 MPa and 2 log10 at 400 MPa were found by application of the pressure at 4 °C. At both temperatures, the virus was nearly completely inactivated (>3.5 log10 infectivity decrease) at 600 MPa; however, low amounts of remaining infectious virus were observed in one of three replicates in both cases. Transmission electron microscopy showed disassembled and distorted particles in the preparations treated with 600 MPa. Time-course experiments at 400 MPa showed a continuous decline of infectivity from 30 s to 10 min, leading to a 2 log10 infectivity decrease at 20 °C and to a 2.5 log10 infectivity decrease at 4 °C for a 10 min pressure application each. Predictive models for inactivation of HEV by HPP were generated on the basis of the generated data. The results show that HPP treatment can reduce HEV infectivity, which is mainly dependent on pressure height and duration of the HPP treatment. Compared to other viruses, HEV appears to be relatively stable against HPP and high pressure/long time combinations have to be applied for significant reduction of infectivity.

Presence of hepatitis E virus in commercially available pork products.

An increasing number of hepatitis E virus (HEV) infections in industrialized countries have been foodborne and linked to the consumption of undercooked pork products. To date, data on the prevalence of HEV in pork products sold in the United States is limited and no standard processing method exists for the detection of HEV in foods. In order to develop a processing method for the detection of HEV in pork products, ground pork and pork liver were selected for method development. Murine norovirus (MNV) was used as a process control. A filtration step prior to RNA detection was shown to reduce the level of PCR inhibitors in ground pork and an additional ultracentrifugation process was successful in removing PCR inhibitors in pork liver. MNV RNA was detected in ground pork and liver samples inoculated with 4.7 log10 PFU/g and 3.0 log10 PFU/g, respectively. Using the developed method for viral RNA detection in ground pork and pork liver, 20 packages of ground pork (six 1 g sub-samples per package) and 14 pork livers (four 1 g sub-samples per liver) were screened for the presence of HEV RNA. Fifteen out of 119 (12.6%) ground pork samples tested positive for HEV RNA and 13 out of 20 packages (65%) contained at least one positive sample. Twenty-five of 56 (45%) of pork liver samples were positive for HEV RNA and 6 of 14 livers (43%) had all sub-samples test positive for HEV RNA. Overall, the results indicate ground pork and pig liver as a potential source of HEV.