Hepatitis A Virus Titers Research Articles

A Cell-Based Electrochemical Biosensor for the Detection of Infectious Hepatitis A Virus

Hepatitis A virus (HAV), a major cause of acute liver infections, is transmitted through the fecal–oral route and close contact with infected individuals. Current HAV standardized methods rely on the detection of virus antigen or RNA, which do not differentiate between infectious and non-infectious HAV. The objective of this study was to develop a prototype cell-based electrochemical biosensor for detection of infectious HAV. A cell culture-adapted HAV strain (HM175/18f) and its permissive cells (FRhK-4), along with gold nanoparticle-modified screen-printed electrodes, were used to develop the biosensor. Electrochemical impedance spectroscopy was used to quantify the electrical impedance signal. Nyquist plots showed successful fabrication of the cell-based biosensor. The optimum period of HAV incubation with the biosensor was 6 h. A significant linear relationship (R2 = 0.98) was found between the signal and a 6-log range of HAV titers, with a limit of detection of ~5 TCID50/mL (tissue culture infectious dose). The biosensor did not detect non-target viruses such as feline calicivirus and human coronavirus 229E. The biosensor was stable for 3 to 7 days at an abusive temperature (37 °C), retaining ~90 to 60% of the original signal, respectively. In conclusion, this prototype cell-based biosensor is capable of rapidly detecting low levels of infectious HAV.

Inactivation of murine norovirus and hepatitis A virus on various frozen fruits using pulsed light

The frozen fruit sector has experienced significant growth due to improved product quality as well as the advantage of long-term preservation. However, freezing alone does not eliminate foodborne viruses, a major public health concern and considerable economic burden. One promising disinfecting treatment is pulsed light, shown previously to inactivate hepatitis A virus (HAV) and murine norovirus-1 (MNV-1) on the surface of fresh berries. Viral loads were reduced by 1–2 log, with minor visual quality deterioration observed. In this study, an FDA-compliant pulsed light treatment (11.52 J/cm2) was applied to frozen fruits and berries. Infectious MNV-1 and HAV titers were reduced by 1–2 log on most frozen fruits. A noteworthy finding was that reductions of both viruses on cranberries exceeded 3.5 log cycles. Although pulsed light caused a measurable rise in temperature on the product surface, no visible physical changes (e.g., color) were observed, and the fruit pieces were still frozen after treatment. Although the reduction of infectious titer by pulsed light alone was not large (1–2 log), considering the low amount of virus typically found on fruit, it may be beneficial in the frozen fruit sector. It would be easy to combine with other treatments, and synergic interactions might increase virus inactivation.

Household dishwashing detergents efficiently inactivate HSV-1, but not the non-enveloped viruses HAV and MNV, while all viruses were removed from glass by manual scrubbing

This study investigated the stability of herpes simplex virus 1 (HSV-1), hepatitis A virus (HAV) and murine norovirus (MNV) on glass, their inactivation by three household dishwashing detergents and during a glass rinsing process. After drying on glass and storage in darkness, virus titers decreased by 4.7, 5.5 and 4.5 log10 plaque forming units (PFU) in 21, 28 and 14 days for HSV-1, HAV and MNV, respectively. Daylight storage resulted in shorter survival times. While HAV and MNV titers were not significantly affected by 60 s incubation in dishwashing detergents at up to 43 °C, HSV-1 titer decreased significantly by > 4 log10 PFU/mL at the same conditions with each detergent used. After cleaning artificially contaminated drinking glasses with a manual glass scrubbing device, HSV-1, HAV and MNV titers decreased significantly by 4.4 ± 0.1 to 5.3 ± 0.0 log10 PFU. Our study shows, that all tested viruses can remain infectious after drying on glass up to several weeks. Household dishwashing detergents efficiently inactivate the enveloped virus HSV-1, but not the non-enveloped viruses HAV and MNV. The applied manual glass rinsing procedure efficiently removed all three viruses from drinking glasses, probably due to the combination of chemical and mechanical treatments.

Synergistic effects of sequential treatment using disinfectant and e-beam for inactivation of hepatitis a virus on fresh vegetables

Hepatitis A virus (HAV) has adversely affected public health worldwide, causing an economic burden on many countries. Fresh vegetables are reported as a source of HAV infections during production, harvesting, and distribution, which cause the emergence of foodborne illnesses. Therefore, in this study, the synergistic effects of chemical (sodium hypochlorite [NaOCl] and chlorine dioxide [ClO2]) and physical (electron-beam [e-beam] irradiation) sequential treatment for HAV inactivation on fresh vegetables were investigated, and the physicochemical quality changes of vegetables were evaluated after each treatment. On bell pepper and cucumber sequentially treated with NaOCl (50–500 ppm) and e-beam (1–5 kGy), the HAV titer was reduced by 0.19–4.69 and 0.28–4.78 log10 TCID50/mL, respectively. Sequential treatment with ClO2 (10–250 ppm) and e-beam (1–5 kGy) reduced the HAV titer on bell pepper and cucumber by 0.41–4.78 and 0.26–4.80 log10 TCID50/mL, respectively. The sequential treatments steadily decreased the HAV titers on each food by a significant difference (p < 0.05) compared to the controls. The treatment combinations of 500 ppm NaOCl and 3 kGy (e-beam) on bell pepper and 150 ppm NaOCl and 1 kGy (e-beam) on cucumber provided maximum synergistic effects. It was also found that sequential treatment with 50 ppm ClO2 and 5 kGy (e-beam) on bell pepper and 10 ppm ClO2 and 5 kGy (e-beam) on cucumber most efficiently inactivated HAV. Additionally, bell pepper and cucumber showed no significant quality changes (p < 0.05) after the treatment. Therefore, the sequential treatment with NaOCl or ClO2 and e-beam is expected to effectively control HAV on fresh vegetables without changing the food quality compared to either treatment alone.

Antiviral Efficacy of Dielectric Barrier Discharge Plasma against Hepatitis A Virus in Fresh Oyster Using PMA/RT-qPCR

The hepatitis A virus (HAV), which can be a threat to humans, can be found in oysters. Oysters need sterilization technology that does not cause quality changes because they are eaten raw. Therefore, in this study, antiviral effects and quality changes were conducted using dielectric barrier discharge plasma (DBDP). Total titers of non-PMA- and PMA-treated suspensions of HAV were reduced to 0.20–1.05 and 0.35–1.49 log10 copies/μL, respectively, after DBDP 10–60 min treatment. HAV titers on oysters were reduced to 0.20–1.11 and 0.33–1.33 log10 copies/μL, respectively, after identical an DBDP treatment of the non-PMA- and PMA-treated oysters. The HAV titers were revealed as 0.295 (=[0.25 for 30 min + 0.34 for 60 min]/2) and 0.22 (for 60 min) log10-reduction in PMA-treated suspensions and oysters, respectively, compared with the non-PMA-treated suspensions and oysters. The D1 of DBDP in PMA-treated suspensions and oysters were 39.99 and 46.73 min, respectively. There was no difference in the pH of oysters after DBDP treatment compared to the non-treated control. There were some changes in the hardness of the DBDP-treated oysters, which was due to oyster individual differences rather than the DBDP treatment. In conclusion, DBDP treatment did not affect oyster quality and PMA was able to distinguish HAV infectivity.

Quantitative Risk Assessment of Hepatitis a Virus Infection Arising from the Consumption of Fermented Clams in South Korea.

This study estimated the risk of hepatitis A virus (HAV) foodborne illness outbreaks through the consumption of fermented clams in South Korea. HAV prevalence in fermented clams was obtained from the Ministry of Food and Drug Safety Report, 2019. Fermented clam samples (2 g) were inoculated with HAV and stored at -20-25 °C. Based on the HAV titer (determined using plaque assay) in fermented clams according to storage, the Baranyi predictive models provided by Combase were applied to describe the kinetic behavior of HAV in fermented clams. The initial estimated HAV contamination level was -3.7 Log PFU/g. The developed predictive models revealed that, when the temperature increased, the number of HAV plaques decreased. The Beta-Poisson model was chosen for determining the dose-response of HAV, and the simulation revealed that there was a 6.56 × 10-11/person/day chance of contracting HAV foodborne illness by eating fermented clams. However, when only regular consumers of fermented clams were assumed as the population, the probability of HAV foodborne illness increased to 8.11 × 10-8/person/day. These results suggest that, while there is a low likelihood of HAV foodborne illness from consuming fermented clams across the country, regular consumers should be aware of the possibility of foodborne illness.

Comparison of the virucidal efficacy of essential oils (cinnamon, clove, and thyme) against hepatitis A virus in suspension and on food-contact surfaces

Essential oils (EOs) have been used for centuries as flavor enhancers in foods, and owing to their antimicrobial properties, they have potential as natural food preservatives. However, their effect on food-borne viruses is unknown. Therefore, in this study, the virucidal effects of three EOs (cinnamon, clove, and thyme) on the infectivity of the hepatitis A virus (HAV) were investigated. Different concentrations of each EO (0.05, 0.1, 0.5, and 1%) were mixed with viral suspensions in accordance with ASTM E1052–11:2011 and incubated for 1 h at room temperature. The EOs exhibited a concentration-dependent effect in the suspension tests, and HAV titers decreased by approximately 1.60 log PFU/mL when treated with EOs at the highest concentration of 1%. The antiviral effect of EOs treated at 1% for 1 h was also evidenced in surface disinfection tests according to the OECD:2013, as approximately 2 log PFU/mL reduction on hard food-contact surfaces (stainless steel and polypropylene) and approximately 2 and 1.4 log PFU/mL reduction on low-density polyethylene and kraft (soft food-contact surfaces), respectively. Moreover, RT-qPCR results revealed that HAV genome copies were negligibly reduced until treated with a high concentration (1%) in suspension and carrier tests. Overall, our findings highlighted the potential of cinnamon, clove, and thyme EOs as natural disinfectants capable of limiting HAV (cross-) contamination conveyed by food-contact surfaces. These findings advance our knowledge of EOs as antimicrobials and their potential in the food sector as alternative natural components to reduce viral contamination and improve food safety.

Survival of murine norovirus and hepatitis A virus in bottled drinking water, strawberries, and oysters

The survival of murine norovirus (MNV) and hepatitis A virus (HAV) in bottled drinking water, strawberries, and oysters stored at different temperatures for various durations was investigated. In drinking water, over 6.4 and 1.6 log 10 plaque-forming units (PFU/mL) reductions of viable MNV and HAV were observed after 20 days of incubation at 35 °C. After 160 days of incubation at 20 °C, there was a sharp decrease in the MNV (>6.4 log 10 PFU/mL) and HAV (>2.9 log 10 PFU/mL) load but only a slight reduction at 4 °C. In fresh strawberry, the MNV and HAV titers reduced by 1.0 and 0.9 log 10 PFU/g after incubation for 2 days at 25 °C, by 0.85 and 1.22 log 10 PFU/g after 3 days of incubation at 15 °C, and by 0.7 and 1.1 log 10 PFU/g after 7 days of incubation at 4 °C, respectively. After 3 days of incubation at 4, 15, and 25 °C in oyster reductions of over 0.3, 0.4, and 0.6 log 10 PFU/mL in the MNV load and 0.16, 0.28, and 0.52 log 10 PFU/mL in the HAV load were observed, respectively. Even though, survival of the two viruses fluctuated with temperature and food commodity. Therefore, our results indicate that major enteric foodborne viruses such as MNV and HAV can survive for long periods, with only a partial reduction in their titers. Owing to the persistence of foodborne viruses, preventive measures need to be taken to prevent food contamination. • MNV and HAV survival in drinking water, strawberries, and oysters was investigated. • MNV and HAV survivability varies with temperature and food type. • Enteric foodborne viruses can persist for a long time at 4 °C. • Study results could lay the foundation for the development of food hazard assessment models.

Antiviral Activity of Essential Oils Against Hepatitis A Virus in Soft Fruits.

Berries have repeatedly been associated with outbreaks of hepatitis A virus (HAV) infection. The fruits are usually minimally processed in the food industry due to their delicate nature. While washing treatments partially remove enteric viruses, the commonly used chemical additives produce toxic by-products. A valid alternative to preserve the food safety of these products could be the use of essential oils (EOs). EOs exert antimicrobial activity and do not interfere with the nutritional characteristics of food products. We investigated the efficacy of four essential oils, lemon (Citrus limon), sweet orange (Citrus sinensis), grapefruit (Citrus paradisi), and rosemary cineole (Rosmarinus officinalis chemotype 1.8 cineole) in reducing viral loads of HAV in soft fruits. Mixed fruit berries were inoculated with 106.74 TCID50/ml of HAV, and treated with four different EOs (0.5% lemon, 0.1% sweet orange and grapefruit, and 0.05% rosemary) for 1h at room temperature. Virus infectivity was then assessed by titration assays for its ability to grow on cell cultures. A statistically significant reduction in HAV titer on the fruit surface was observed after treating the berries with EOs of lemon (2.84 log TCID50/ml), grapefruit (2.89 log TCID50/ml), and rosemary cineole (2.94 log TCID50/ml). Rosemary cineole was the most effective EO in reducing viral titer on berries, followed by grapefruit EO. These results improve our knowledge about the antiviral activity of these EOs and highlight their potential use in fresh produce sanitation.

Ultraviolet C light efficiently inactivates nonenveloped hepatitis A virus and feline calicivirus in platelet concentrates.

Nonenveloped transfusion-transmissible viruses such as hepatitis A virus (HAV) and hepatitis E virus (HEV) are resistant to many of the common virus inactivation procedures for blood products. This study investigated the pathogen inactivation (PI) efficacy of the THERAFLEX UV-Platelets system against two nonenveloped viruses: HAV and feline calicivirus (FCV), in platelet concentrates (PCs). PCs in additive solution were spiked with high titers of cell culture-derived HAV and FCV, and treated with ultraviolet C at various doses. Pre- and posttreatment samples were taken and the level of viral infectivity determined at each dose. For some samples, large-volume plating was performed to improve the detection limit of the virus assay. THERAFLEX UV-Platelets reduced HAV titers in PCs to the limit of detection, resulting in a virus reduction factor of greater than 4.2 log steps, and reduced FCV infectivity in PCs by 3.0 ± 0.2 log steps. THERAFLEX UV-Platelets effectively inactivates HAV and FCV in platelet units.

UV-C inactivation of foodborne bacterial and viral pathogens and surrogates on fresh and frozen berries

Outbreaks of foodborne illness associated with berries often involve contamination with hepatitis A virus (HAV) and norovirus but also bacteria such as Escherichia coli O157:H7 and parasites such as Cyclospora caytanensis. We evaluated the applicability of UV-C to the inactivation of pathogens on strawberries, raspberries and blueberries. Our three-step approach consisted of assessing the chemical safety of UV-C-irradiated berries, evaluating the sensory quality after UV-C treatment and finally studying the inactivation of the target microorganisms. Treatments lasting up to 9 min (4000 mJ cm−2) did not produce detectable levels of furan (<5 μg/kg), a known photolysis product of fructose with genotoxic activity and thus were assessed to be toxicologically safe. No effect on taste or appearance was observed, unless treatment was excessively long. 20 s of treatment (an average fluence of ~ 212 mJ cm−2) reduced active HAV titer by >1 log10 unit in 95% of cases except on frozen raspberries, while 120 s were required to inactivate murine norovirus to this extent on fresh blueberries. The mean inactivation of HAV and MNV was greater on blueberries (2–3 log10) than on strawberries and raspberries (<2 log10). MNV was more sensitive on fresh than on frozen berries, unlike HAV. Inactivation of Salmonella, E. coli O157:H7 and Listeria monocytogenes was poor on all three berries, no treatment reducing viable counts by >1 log10 unit. In most matrices, prolonging the treatment did not improve the result to any significant degree. The effect was near its plateau after 20 s of treatment. These results provide insight into the effectiveness of UV-C irradiation for inactivating bacterial and viral pathogens and surrogates on fresh and frozen berries having different surface types, under different physical conditions and at different levels of contamination. Overall they show that UV-C as single processing step is unsuitable to inactivate significant numbers of foodborne pathogens on berries.

Assessment of cold oxygen plasma technology for the inactivation of major foodborne viruses on stainless steel

This study investigated the efficacy of cold oxygen plasma (COP) for inactivation of murine norovirus-1 (MNV-1; a human norovirus [NoV] surrogate) and hepatitis A virus (HAV) on stainless steel surfaces. Decrease in the MNV-1 and HAV titers resulting from 10 to 300 s of COP were 0.27–3.89 and 0.77–2.02 log PFU/ml, respectively. The Weibull model was used to calculate D-values of 1, 2, and 3-log reductions as the treatment times for MNV-1 (R2 = 0.95, RMSE = 0.08) and HAV (R2 = 0.96, RMSE = 0.05). The D = 2 and D = 3 values for MNV-1 (0.72 min for D = 2, 4.98 min for D = 3) were less than those for HAV (1.43 min for D = 2, 9.99 min for D = 3). However, there was no significant difference in values for D = 1 by COP between MNV-1 (21.65 s) and HAV (25.10 s). COP treatment on food contact surfaces could be effective for inactivation of NoV and HAV.

Effect of green tea extract on enteric viruses and its application as natural sanitizer

In this work, the effect of green tea extract (GTE) was assessed against murine norovirus (MNV) and hepatitis A virus (HAV) at different temperatures, exposure times and pH conditions. Initially, GTE at 0.5 and 5 mg/ml were individually mixed with each virus at 5 log TCID50/ml and incubated 2 h at 37 °C at different pHs (from 5.5 to 8.5). GTE affected both viruses depending on pH with higher reductions observed in alkaline conditions. Secondly, different concentrations of GTE (0.5 and 5 mg/ml) were mixed with viral suspensions and incubated for 2 or 16 h at 4, 25 and 37 °C at pH 7.2. A concentration-, temperature- and exposure time-dependent response was showed by GTE in suspension tests, where complete inactivation was achieved after overnight exposure at 37 °C for both viruses and also at 25 °C for HAV.In addition, antiviral effect of GTE proved efficient in the surface disinfection tests since 1.5 log reduction and complete inactivation were recorded for MNV and HAV on stainless steel and glass surfaces treated with 10 mg/ml GTE for 30 min, analyzed in accordance with ISO 13697:2001. GTE was also evaluated as a natural disinfectant of produce, showing 10 mg/ml GTE reduced MNV and HAV titers in lettuce and spinach by more than 1.5 log after 30 min treatment.The results show a potential of GTE as natural disinfectant able to limit enteric viral (cross-)contaminations conveyed by food and food-contact surfaces.

Antiviral activity of herbal extracts against the hepatitis A virus

Herbal plants have long been used as traditional medicines to treat diseases caused by microbial pathogens. The hepatitis A virus (HAV) causes acute liver infection through the fecal–oral route. Although the antimicrobial activities of herbal extracts against bacterial and some viral pathogens have been extensively studied, their antiviral properties against HAV have not been investigated thus far. This study was designed to investigate the inhibitory effect of 16 herbal extracts against HAV. Significant inhibition of HAV was observed only when HAV was co-treated with extracts. Ten out of the 16 herbal extracts demonstrated significant virucidal activity against HAV. Alnus japonica extract at a concentration of 50 μg/mL reduced HAV titer by 3.43 ± 0.24 logs. Artemisia annua, Allium sativum, Allium fistulosum, and Agrimonia pilosa extracts showed 2.33 ± 0.43, 2.10 ± 0.41, 2.07 ± 0.60, and 2.03 ± 0.26-log reductions, respectively. Pleuropterus multiflorus, Eleutherococcus senticosus, Coriandrum sativum, Ginkgo biloba, and Torilis japonica extracts reduced HAV titer by 1.02 ± 0.21 to 1.90 ± 0.33 logs. Among the 10 herbal extracts, Alnus japonica extract was the most potent in inhibiting HAV without exhibiting cytotoxicity.

Reduction of Enteric Viruses by Blueberry Juice and Blueberry Proanthocyanidins.

Blueberry and blueberry extracts are known for their health benefits and antimicrobial properties. Natural therapeutic or preventive options to decrease the incidences of foodborne viral illnesses are becoming popular and being researched. This study aimed to determine the antiviral effects of blueberry juice (BJ) and blueberry proanthocyanidins (BB-PAC, B-type PAC structurally different from A-type PAC found in cranberries) against the infectivity of hepatitis A virus (HAV) and human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) at 37°C over 24 h using standard plaque assays. Viruses at~5 log PFU/ml were mixed with equal volumes of BJ (pH 2.8), neutralized BJ (pH 7.0), BB-PAC (1, 2, 4, and 10mg/ml), malic acid (pH 3.0), or phosphate-buffered saline (pH 7.2) and incubated over 24 h at 37°C. Each experiment was carried out in duplicate and replicated thrice. FCV-F9 titers were found to be reduced to undetectable levels with 1 and 2mg/ml BB-PAC after 5min, with 0.5mg/ml BB-PAC after 1-h, and with BJ after 3-h. MNV-1 titers were reduced to undetectable levels after 3 h with 1, 2, and 5mg/ml BB-PAC and after 6 h with BJ. HAV titers were reduced to undetectable levels after 30min with 2 and 5mg/ml BB-PAC, after 3 h with 1mg/ml BB-PAC, and by~2 log PFU/ml with BJ after 24-h. BB-PAC shows preventive potential against infection by the tested enteric viruses in a dose- and time-dependent manner, although further in vitro studies in model food systems and in vivo studies using animal models are warranted.

Efficacy of Cinnamaldehyde Against Enteric Viruses and Its Activity After Incorporation Into Biodegradable Multilayer Systems of Interest in Food Packaging.

Cinnamaldehyde (CNMA), an organic compound that gives cinnamon its flavor and odor, was investigated for its virucidal activity on norovirus surrogates, murine norovirus (MNV) and feline calicivirus (FCV), and hepatitis A virus (HAV). Initially, different concentrations of CNMA (0.1, 0.5 and 1%) were individually mixed with each virus at titers of ca. 6-7 log10 TCID50/ml and incubated 2h at 4 and 37°C. CNMA was effective in reducing the titers of norovirus surrogates in a dose-dependent manner after 2h at 37°C, while HAV titers were reduced by 1 log10 after treatment with 1% of CNMA. When incubation time was extended, HAV titers were reduced by 3.4 and 2.7 log10 after overnight incubation at 37°C with 1 and 0.5% of CNMA, respectively. Moreover, this paper analyzed, for the first time, the antiviral activity of adding an active electrospun interlayer based on zein and CNMA to a polyhydroxybutyrate packaging material (PHB) in a multilayer form. Biodegradable multilayer systems prepared with 2.60mg/cm(2) (~9.7%) of CNMA completely inactivated FCV according to ISO 22196:2011, while MNV titers were reduced by 2.75 log10. When the developed multilayer films were evaluated after one month of preparation or at 25°C, the antiviral activity was reduced as compared to freshly prepared multilayer films evaluated at 37°C. The results show the excellent potential of this system for food contact applications as well as for active packaging technologies in order to maintain or extend food quality and safety.

Ultraviolet-C efficacy against a norovirus surrogate and hepatitis A virus on a stainless steel surface

In this study, the effects of 10–300mWs/cm2 of ultraviolet radiation (UV-C) at 260nm were investigated for the inactivation of two foodborne viruses: murine norovirus-1 (MNV-1; a human norovirus [NoV] surrogate) and hepatitis A virus (HAV). We used an experimentally contaminated stainless steel surface, a common food-contact surface, to examine the effects of low doses of UV-C radiation on MNV-1 and HAV titers. The modified Gompertz equation was used to generate non-linear survival curves and calculate dR-values as the UV-C dose of 90% reduction for MNV-1 (R2=0.95, RMSE=0.038) and HAV (R2=0.97, RMSE=0.016). Total MNV-1 and HAV titers significantly decreased (p<0.05) with higher doses of UV-C. MNV-1 and HAV were reduced to 0.0–4.4 and 0.0–2.6 log10PFU/ml, respectively, on the stainless steel surfaces by low-dose UV-C treatment. The dR-value, 33.3mWs/cm2 for MNV-1 was significantly (p<0.05) lower than 55.4mWs/cm2 of HAV. Therefore, the present study shows that HAV is more resistant to UV-C radiation than MNV-1. These data suggest that low doses of UV-C light on food contact surfaces could be effective to inactivate human NoV and HAV in restaurant, institutional, and industrial kitchens and facilities.

Inactivation of murine norovirus-1 and hepatitis A virus on fresh meats by atmospheric pressure plasma jets

In the current study, inactivation effect of atmospheric pressure plasma (APP) jets (10s–20min) was investigated against murine norovirus (MNV-1), as a norovirus (NoV) surrogate and hepatitis A virus (HAV) associated with three types of fresh meats (beef loin, pork shoulder and chicken breast). The quality characteristics of fresh meats, such as surface color, moisture content and thiobarbituric acid reactive substance (TBARS) were also examined. After 5–20min of treatment with APP jets, the reduction in MNV-1 titers (initial inoculums of 107 plaque-forming units (PFU)) were >2log10PFU/mL in the three types of meat. After 5–20min treatment with APP jets, the reduction in HAV titers (initial inoculums of 106PFU) were >1log10PFU/mL in the three types of meat. There was no significant difference (p>0.05) in the L*, a*, and b* values for APP jet treatment times below 5min. Furthermore, there was no significant difference (p>0.05) in the water content (%) value for treatment times under 5min. Although the TBARS values gradually increased with increase in APP jet treatment times, these TBA values were below 1.0mgMA/kg (an indicator of meat rancidity). The results of the current study indicate that 5min of APP jet treatment showed >99% reduction (2log10PFU/mL) of MNV-1 titer and >90% reduction (1log10PFU/mL) of HAV titer without concomitant changes in meat quality; thus, this procedure can be considered in fresh meat production, processing and distribution processes to enhance fresh meat safety.

Aqueous Extracts of Hibiscus sabdariffa Calyces Decrease Hepatitis A Virus and Human Norovirus Surrogate Titers.

Hibiscus sabdariffa extract is known to have antioxidant, anti-diabetic, and antimicrobial properties. However, their effects against foodborne viruses are currently unknown. The objective of this study was to determine the antiviral effects of aqueous extracts of H. sabdariffa against human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and hepatitis A virus (HAV) at 37 °C over 24 h. Individual viruses (~5 log PFU/ml) were incubated with 40 or 100 mg/ml of aqueous hibiscus extract (HE; pH 3.6), protocatechuic acid (PCA; 3 or 6 mg/ml, pH 3.6), ferulic acid (FA; 0.5 or 1 mg/ml; pH 4.0), malic acid (10 mM; pH 3.0), or phosphate buffered saline (pH 7.2 as control) at 37 °C over 24 h. Each treatment was replicated thrice and plaque assayed in duplicate. FCV-F9 titers were reduced to undetectable levels after 15 min with both 40 and 100 mg/ml HE. MNV-1 was reduced by 1.77 ± 0.10 and 1.88 ± 0.12 log PFU/ml after 6 h with 40 and 100 mg/ml HE, respectively, and to undetectable levels after 24 h by both concentrations. HAV was reduced to undetectable levels by both HE concentrations after 24 h. PCA at 3 mg/ml reduced FCV-F9 titers to undetectable levels after 6 h, MNV-1 by 0.53 ± 0.01 log PFU/ml after 6 h, and caused no significant change in HAV titers. FA reduced FCV-F9 to undetectable levels after 3 h and MNV-1 and HAV after 24 h. Transmission electron microscopy showed no conclusive results. The findings suggest that H. sabdariffa extracts have potential to prevent foodborne viral transmission.

Ultraviolet-C Radiation on the Fresh Chicken Breast: Inactivation of Major Foodborne Viruses and Changes in Physicochemical and Sensory Qualities of Product

This study investigated the effects of diverse doses (60–3600 mWs/cm2) of ultraviolet radiation (UV-C; 260 nm) on the inactivation of two types of foodborne viruses, the hepatitis A virus (HAV) and murine norovirus-1 (MNV-1; a human norovirus surrogate). Experimentally contaminated fresh chicken breasts were used as substrates, and the effects of UV-C radiation on the physicochemical properties and sensory qualities of chicken breasts were examined. MNV-1 and HAV titers significantly decreased (P < 0.05) when fresh chicken breasts were progressively irradiated with UV-C light. Over 1 log reduction in the titers of MNV-1 (1.23 log) and HAV (1.17 log) was detected when fresh chicken breasts were irradiated with 3600 mWs/cm2 of UV-C light. The calculated D-values for MNV-1 and HAV titers fell in the range of 3138.88–3428.57 and 2854.12–3076.92 mWs/cm2, respectively. Chicken breasts exposed to higher doses of UV-C radiation turned darker, exhibited more redness, and displayed prominent shades of yellow color. These changes strongly correlated with a decrease in the Hunter “L” values and an increase in the Hunter “a” and Hunter “b” values, respectively. This was also accompanied by an increase in the lipid peroxidation of the breast meat, which resulted in higher thiobarbituric acid reactive substance (TBARS) values. However, the UV-C radiation did not induce any pH changes into the food product. Chicken breasts treated with over 1800 mWs/cm2 of UV-C radiation displayed compromised sensory properties, whereas those treated with 60–1200 mWs/cm2 of UV-C witnessed satisfactory consumer acceptance. Therefore, the current study suggests that the use of the 600–1200 mWs/cm2 of UV-C radiation, in combination with other decontamination techniques (such as the hygienic processing of chicken breasts in well-sanitized processing plants), could be very effective in reducing more than 90 % (1 log) of the MNV-1 and HAV counts, without causing any deleterious changes to the physicochemical and sensory qualities of the meat surface.