scholarly journals Pilot scale study on UV-C inactivation of bacterial endospores and virus particles in whole milk: evaluation of system efficiency and product quality

2022 ◽  
Author(s):  
Pranav Vashisht ◽  
Brahmaiah Pendyala ◽  
Ankit Patras ◽  
Vybhav Vipul Sudhir Gopisetty ◽  
Ramasamy Ravi
Keyword(s):  
Pilot Scale ◽  
Microbial Inactivation ◽  
Dean Number ◽  
Experimental Conditions ◽  
Virus Particles ◽  
Dean Flow ◽  
Log Reduction ◽  
Bacterial Endospores ◽  
Whole Milk ◽  
Uv C

UV-C processing of whole milk (WM) using a designed pilot scale Dean flow system was conducted at flow rates (11.88, 23.77, and 47.55 gph), Reynolds number ranges from 2890-11562 and the Dean number (at curved region) calculated as (648-2595) to inactivate bacterial endospores and virus particles. Biodosimetry studies were conducted to quantify the reduction equivalent fluence at selected experimental conditions. Results revealed that the dose distribution improved as flow rate increases, attributed to increase in Dean effects and turbulence intensity. Microbial inactivation studies conducted at 47.55 gph showed 0.91 (stdev:0.15) and 2.14 (stdev:0.19) log reduction/ pass for B. cereus endospores and T1UV phage. Linear inactivation trend was observed against number of passes which clearly demonstrates equivalent dose delivery during each pass. Lipid peroxidation value and volatile profile did not change significantly at UV dose of 60 mJ/cm 2. Lower E EO value signifies the higher electrical efficiency of the system.

scholarly journals Mitigation of Airborne PRRSV Transmission with UV Light Treatment: Proof-of-concept

2021 ◽  
Author(s):  
Peiyang Li ◽  
Jacek A. Koziel ◽  
Jeffrey J. Zimmerman ◽  
Jianqiang Zhang ◽  
Ting-Yu Cheng ◽  
...  
Keyword(s):  
Uv Light ◽  
Pilot Scale ◽  
Respiratory Syndrome Virus ◽  
Two Stage ◽  
Short Treatment ◽  
Log Reduction ◽  
Stage Models ◽  
One Stage ◽  
Order Of Magnitude ◽  
Uv C

Proper treatment of infectious air could potentially mitigate the spread of airborne viruses such as porcine reproductive and respiratory syndrome virus (PRRSV). The objective of this research is to test the effectiveness of ultraviolet (UV) in inactivating aerosolized PRRSV, specifically, four UV lamps, UV-A (365 nm, both fluorescent and LED-based), "excimer" UV-C (222 nm), and germicidal UV-C (254 nm), were tested. The two UV-C lamps effectively irradiated fast-moving PRRSV aerosols with short treatment times (<2 s). One-stage and two-stage UV inactivation models estimated the UV doses needed for target percentage (%) reductions on PRRSV titer. UV-C (254 nm) dose needed for 3-log (99.9%) reduction was 0.521 and 0.0943 mJ/cm2, respectively, based on one-stage and two-stage models. An order of magnitude lower UV-C (222 nm) doses were needed for a 3-log reduction, i.e., 0.0882 and 0.048 mJ/cm2, based on one-stage and two-stage models, respectively. However, the cost of 222-nm excimer lamps is still economically prohibitive for scaling-up trials. The UV-A (365 nm) lamps could not reduce PRRSV titers for tested doses up to 4.11 mJ/cm2. Pilot-scale or farm-scale testing of UV-C on PRRSV aerosols simulating barn ventilation rates are recommended based on its effectiveness and reasonable costs comparable to HEPA filtration.

scholarly journals Survival of Escherichia coli O157:H7 during Moderate Temperature Dehydration of Plant-Based Foods

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2162
Author(s):  
Yadwinder Singh Rana ◽  
Philip M. Eberly ◽  
Quincy J. Suehr ◽  
Ian M. Hildebrandt ◽  
Bradley P. Marks ◽  
...  
Keyword(s):  
Pilot Scale ◽  
Microbial Inactivation ◽  
Moderate Temperature ◽  
Isothermal Treatment ◽  
Pathogen Inactivation ◽  
Decimal Reduction Time ◽  
E Coli ◽  
Log Reduction ◽  
D Values ◽  
Time Required

The effect of moderate-temperature (≤60 °C) dehydration of plant-based foods on pathogen inactivation is unknown. Here, we model the reduction of E. coli O157:H7 as a function of product-matrix, aw, and temperature under isothermal conditions. Apple, kale, and tofu were each adjusted to aw 0.90, 0.95, or 0.99 and inoculated with an E. coli O157:H7 cocktail, followed by isothermal treatment at 49, 54.5, or 60.0 °C. The decimal reduction time, or D-value, is the time required at a given temperature to achieve a 1 log reduction in the target microorganism. Modified Bigelow-type models were developed to determine D-values which varied by product type and aw level, ranging from 3.0–6.7, 19.3–55.3, and 45.9–257.4 min. The relative impact of aw was product dependent and appeared to have a non-linear impact on D-values. The root mean squared errors of the isothermal-based models ranged from 0.75 to 1.54 log CFU/g. Second, we performed dynamic drying experiments. While the isothermal results suggested significant microbial inactivation might be achieved, the dehydrator studies showed that the combination of low product temperature and decreasing aw in the pilot-scale system provided minimal inactivation. Pilot-scale drying at 60 °C only achieved reductions of 3.1 ± 0.8 log in kale and 0.67 ± 0.66 log in apple after 8 h, and 0.69 ± 0.67 log in tofu after 24 h. This illustrates the potential limitations of dehydration at ≤60 °C as a microbial kill step.

scholarly journals Mitigation of Airborne PRRSV Transmission with UV Light Treatment: Proof-of-Concept

Agriculture ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 259
Author(s):  
Peiyang Li ◽  
Jacek A. Koziel ◽  
Jeffrey J. Zimmerman ◽  
Jianqiang Zhang ◽  
Ting-Yu Cheng ◽  
...  
Keyword(s):  
Uv Light ◽  
Pilot Scale ◽  
Respiratory Syndrome Virus ◽  
Two Stage ◽  
Short Treatment ◽  
Log Reduction ◽  
Stage Models ◽  
One Stage ◽  
Order Of Magnitude ◽  
Uv C

Proper treatment of infectious air could potentially mitigate the spread of airborne viruses such as porcine reproductive and respiratory syndrome virus (PRRSV). The objective of this research is to test the effectiveness of ultraviolet (UV) in inactivating aerosolized PRRSV, specifically, four UV lamps, UV-A (365 nm, both fluorescent and LED-based), “excimer” UV-C (222 nm), and germicidal UV-C (254 nm), were tested. The two UV-C lamps effectively irradiated fast-moving PRRSV aerosols with short treatment times (<2 s). One-stage and two-stage UV inactivation models estimated the UV doses needed for target percentage (%) reductions on PRRSV titer. UV-C (254 nm) dose needed for 3-log (99.9%) reduction was 0.521 and 0.0943 mJ/cm2, respectively, based on one-stage and two-stage models. An order of magnitude lower UV-C (222 nm) doses were needed for a 3-log reduction, i.e., 0.0882 and 0.048 mJ/cm2, based on one-stage and two-stage models, respectively. However, the cost of 222 nm excimer lamps is still economically prohibitive for scaling-up trials. The UV-A (365 nm) lamps could not reduce PRRSV titers for tested doses up to 4.11 mJ/cm2. Pilot-scale or farm-scale testing of UV-C on PRRSV aerosols simulating barn ventilation rates are recommended based on its effectiveness and reasonable costs comparable to HEPA filtration.

scholarly journals Microbial stabilization of grape musts and wines using coiled UV-C reactor

OENO One ◽  
2020 ◽  
Vol 54 (1) ◽  
Author(s):  
Rémy Junqua ◽  
Emmanuel Vinsonneau ◽  
Rémy Ghidossi
Keyword(s):  
Microbial Inactivation ◽  
Operating Conditions ◽  
Water Disinfection ◽  
Industrial Scale ◽  
Hydrodynamic Characteristics ◽  
Dean Number ◽  
Multiple Strains ◽  
Inactivation Efficiency ◽  
The Impact ◽  
Uv C

UV-C light is well known for its germicidal properties and is widely used for water disinfection. However, its low penetration into absorbing liquids, such as wines and musts, reduces drastically the microbial inactivation effectiveness. Additionally, wines require UV-C doses to be as low as possible to avoid any possible light-struck flavors. In order to add to the technologies that allow the reduction of SO2 use, a coiled UV-C reactor was designed to inactivate microorganisms in wines and musts. Due to its unique hydrodynamic characteristics, this design could improve the exposure probabilities of the microorganisms to the UV-C light in absorbing liquids. In a first step, theoretical and measured fluid dynamics parameters such as Dean number were employed to improve the operating conditions of the reactor. The higher the Dean number, the higher the UV-C dose delivery efficiency in this reactor, and thus the lower the dose required to inactivate a given load of microorganisms. The second step investigated the impact of different wines on microbial inactivation efficiency and the UV-C doses required to inactivate microorganisms frequently found in wines. White and rosé wines, with low absorbances at 254 nm, required lower doses (≈ 600 J/L) than red wine (≈ 5000 J/L) because their absorption coefficient is ten times lower. The tolerance of microbial strains to UV-C treatments was variable, with higher resistance observed for yeast than for bacteria. In the third step, treatments conducted at semi-industrial scale showed that physicochemical and sensorial properties of wines and musts were not altered, highlighting the possible relevance of such a reactor on an industrial scale. Highlights: • Design of a coiled UV-C reactor for microbial stabilization of wines and musts• Focus on inactivation efficiency in multiple strains and wine varieties• Chemical and sensorial analyses to ensure treatment does not affect the organoleptic properties of the product

scholarly journals UV‐C treatment on the safety of skim milk: Effect on microbial inactivation and cytotoxicity evaluation

2018 ◽  
Vol 42 (4) ◽  
Author(s):  
Danielle M. Ward ◽  
Ankit Patras ◽  
Agnes Kilonzo‐Nthenge ◽  
Sudheer K. Yannam ◽  
Che Pan ◽  
...  
Keyword(s):  
Skim Milk ◽  
Microbial Inactivation ◽  
Uv C

Antimicrobial Effects of d-3-Phenyllactic Acid on Listeria monocytogenes in TSB-YE Medium, Milk, and Cheese

1998 ◽  
Vol 61 (10) ◽  
pp. 1281-1285 ◽  
Author(s):  
VIRGINIE DIEULEVEUX ◽  
MICHELINE GUÉGUEN
Keyword(s):  
Listeria Monocytogenes ◽  
Growth Phase ◽  
Physiological State ◽  
Geotrichum Candidum ◽  
Bactericidal Effect ◽  
Exponential Growth Phase ◽  
Bacteriostatic Effect ◽  
Experimental Conditions ◽  
Phenyllactic Acid ◽  
Whole Milk

d-3-Phenyllactic acid is a compound with anti-Listeria activity which is produced and secreted by the yeastlike fungus, Geotrichum candidum. This compound has a bactericidal effect independent of the physiological State of Listeria monocytogenes when added at a concentration of 7 mg/ml to tryptic soy broth supplemented with yeast extract (TSB-YE). An initial L. monocytogenes population of 105 CFU/ml was reduced 100-fold (2 log) after 4 days of culture at 25 °C in TSB-YE containing d-3-phenyllactic acid. The Listeria population was reduced 1,000-fold (3 log) when the compound was added during the exponential growth phase, and was reduced to less than 10 CFU/ml when it was added during the stationary phase. d-3-Phenyllactic acid had a bacteriostatic effect in UHT whole milk, reducing the population by 4.5 log, to give fewer cells than in the control after 5 days of culture. The results obtained with L. monocytogenes at concentrations of 105 and 103 CFU/ml in cheese curds were less conclusive. d-3-Phenyllactic acid was 10 times less active than nisin in our experimental conditions (TSB-YE at 25°C).

scholarly journals 1215. Ultraviolet-C (UV-C) Monitoring Made Ridiculously Simple: UV-C Dose Indicators for Convenient Measurement of UV-C Dosing

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S437-S437
Author(s):  
Jennifer Cadnum ◽  
Annette Jencson ◽  
Sarah Redmond ◽  
Thriveen Sankar Chittoor Mana ◽  
Curtis Donskey
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Fetal Calf Serum ◽  
Color Change ◽  
Calf Serum ◽  
Organic Load ◽  
Healthcare Facilities ◽  
Log Reduction ◽  
Ultraviolet C ◽  
Effective Doses ◽  
Uv C

Abstract Background Ultraviolet-C (UV-C) light is increasingly used as an adjunct to standard cleaning in healthcare facilities. However, most facilities do not have a means to measure UV-C to determine whether effective doses are being delivered. We tested the efficacy of 2 easy-to-use colorimetric indicators for monitoring UV-C dosing in comparison to log reductions in pathogens. Methods In a laboratory setting, we exposed methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile spores on steel disk carriers with or without an organic load (5% fetal calf serum) to UV-C for varying times resulting in fluence exposures ranging from 10,000 to 100,000 µJ/cm2. The UV-C indicators were placed adjacent to the carriers. Log reductions were calculated in comparison to untreated controls and the change in color of the indicators was correlated with dose and log reductions. Results The UV-C doses required to achieve a 3-log reduction in MRSA and C. difficile were 10,000 and 46,000 µJ/cm2, respectively. For both indicators, there was a visible color change from baseline at 10,000 µJ/cm2 and a definite final color change by 46,000 µJ/cm2 (Figure 1). Organic load had only a modest impact on UV-C efficacy. The indicators required only a few seconds to place and were easy to read (Figure 2). Conclusion UV-C doses of 10,000 and 46,000 µJ/cm2 were required to achieve 3 log reductions of MRSA and C. difficile spores, respectively. The colorimetric indicators provide an easy means to monitor UV-C dosing. Disclosures All authors: No reported disclosures.

Effects of high pressure homogenisation of raw bovine milk on alkaline phosphatase and microbial inactivation. A comparison with continuous short-time thermal treatments

2006 ◽  
Vol 73 (4) ◽  
pp. 454-463 ◽  
Author(s):  
Laëtitia Picart ◽  
Maryse Thiebaud ◽  
Malika René ◽  
Joseph Pierre Guiraud ◽  
Jean Claude Cheftel ◽  
...  
Keyword(s):  
High Pressure ◽  
Alkaline Phosphatase ◽  
Micrococcus Luteus ◽  
Bovine Milk ◽  
Microbial Reduction ◽  
Microbial Inactivation ◽  
Thermal Treatments ◽  
Globule Size ◽  
Whole Milk ◽  
Short Time

Raw whole milk of high microbial quality ([les ]4×104 cfu/ml) was processed using a ~15 l/h homogeniser with a high pressure (HP) valve immediately followed by cooling heat exchangers. The effects of homogenisation between 100 and 300 MPa (HP valve) with an initial milk temperature Tin=4 °C or 24 °C was investigated on the inactivation of: (i) endogenous alkaline phosphatase (ALP); (ii) endogenous milk flora and (iii) two Gram positive (Listeria innocua and Micrococcus luteus) and one Gram negative (Pseudomonas fluorescens) strains inoculated into milk. Temperatures T1 and T2 measured before and immediately after the HP valve, and fat globule size distributions were also determined. ALP activity slightly decreased after homogenisation above 250 MPa when Tin=4 °C (corresponding T2>58 °C), but markedly decreased above 200 MPa when Tin=24 °C (T2>60 °C). In contrast to inactivation induced by continuous short-time thermal treatments, ALP inactivation induced by HP homogenisation was clearly due to mechanical forces (shear, cavitation and/or impact) in the HP valve and not to the short ([Lt ]1 s) residence time at temperature T2 in the same valve. Inactivation of the three exogenous microorganisms led to similar conclusions. Homogenisation at 250 MPa or 300 MPa (Tin=24 °C) induced a 2–3 log cycle reduction of the total endogenous milk flora and a 1·5–1·8 log cycle reduction of inoculated List. innocua. Higher reduction ratios (2–4 log cycles) were obtained for the two other microorganisms. The highest levels of ALP inactivation corresponded to the highest extents of microbial reduction. Running the milk twice or three times through the homogeniser (recycling), keeping temperature T1≈29 °C and pressure=200 MPa, increased homogenisation efficiency.

SPECTRAL NUMERICAL SIMULATION OF MAGNETO-PHYSIOLOGICAL LAMINAR DEAN FLOW

2014 ◽  
Vol 14 (04) ◽  
pp. 1450047 ◽  
Author(s):  
O. ANWAR BEG ◽  
MD. MAINUL HOQUE ◽  
M. WAHIDUZZAMAN ◽  
MD. MAHMUD ALAM ◽  
M. FERDOWS
Keyword(s):  
Transport Model ◽  
Computational Simulation ◽  
Large Diameter ◽  
Experimental Studies ◽  
Circular Cross Section ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Momentum Conservation ◽  
Dean Number ◽  
Dean Flow

A computational simulation of magnetohydrodynamic laminar blood flow under pressure gradient through a curved bio-vessel, with circular cross-section is presented. Electrical conductivity and other properties of the biofluid (blood) are assumed to be invariant. A Newtonian viscous flow (Navier–Stokes magnetohydrodynamic) model is employed which is appropriate for large diameter blood vessels, as confirmed in a number of experimental studies. Rheological effects are therefore neglected as these are generally only significant in smaller diameter vessels. Employing a toroidal coordinate system, the steady-state, three-dimensional mass and momentum conservation equations are developed. With appropriate transformations, the transport model is non-dimensionalized and further simplified to a pair of axial and secondary flow momenta equations with the aid of a stream function. The resulting non-linear boundary value problem is solved with an efficient, spectral collocation algorithm, subject to physically appropriate boundary conditions. The influence of magnetic body force parameter, Dean number and vessel curvature on the flow characteristics is examined in detail. For high magnetic parameter and Dean number and low curvature, the axial flow is observed to be displaced toward the center of the vessel with corresponding low fluid particle vorticity strengths. Visualization is achieved with the MAPLE software. The simulations are relevant to cardiovascular biomagnetic flow control.

Sign in / Sign up

Export Citation Format

Share Document