The Need to Rethink Harm Reduction for People Using Drugs Alone to Reduce Overdose Fatalities.

Background: During the ongoing opioid epidemic, Cuyahoga County (second largest in Ohio) reported overdose mortality rates (54/per 100,000) higher than the national average. Prior research demonstrates that people who use drugs often use alone but there is minimal research on people who died of overdose while using alone. The objective of this study is to examine sociodemographic, toxicologic, and injury characteristics, and emergency medical response to overdose decedents who died using drugs alone. Method: Data from the Cuyahoga County Medical Examiner's Office (2016-2020, N = 2944) on unintentional overdose deaths in adults was tabulated including socio-demographic, toxicologic, and injury-related information. Decedents using drugs alone were identified and compared to those not using alone via Chi-square and Fisher's exact tests. We further fit a multivariate logistic regression model to evaluate socio-demographic, toxicologic, and injury-related factors associated with increased odds of using alone. All results are reported with 95% confidence intervals. Result: Among decedents, 75% (n = 2205) were using drugs alone. Decedents using alone were more likely to be using drugs at home (p = 0.001) or be found dead at the scene (p < 0.001) and less likely to receive naloxone (p < 0.001) have other person/bystander, not using, present (p = 0.002). Using drugs at home (aOR = 1.61[1.19-2.20]) was associated with higher odds of using alone; and being married (aOR = 0.57[0.38-0.86]), having history of illicit drug use (aOR = 0.25[0.08-0.81]) and other person present, who was not using (aOR = 0.58[0.42-0.79]) were associated with lower odds of using alone. Conclusion: New harm reduction approaches targeting people using drugs alone are needed to reduce overdose deaths.

The Public Health Role of Medical Examiner Offices During COVID-19 and Other Mass Fatality Events.

ABSTRACT: The public health role of a medical examiner office (MEO) in a pandemic is largely undefined; however, death data may be useful in strategic planning. Deaths reportable to MEO are defined in statute, with discretion as to the assumption of jurisdiction. We analyzed the daily reported death numbers (DRDNs) in our jurisdiction from March 1, 2020, to March 31, 2021, and compared them with hospital admission and COVID-19 fatality data over the same period. The DRDN from an MEO is easily obtained and may be useful as a supplemental and surrogate metric in certain pandemic mass casualty decisions. Hospital admission data were analyzed in real time and with a 2-week time-shift, as deaths lag hospital admissions as a disease surveillance metric. Moderate correlation was observed between DRDN and hospital admissions (r = 0.570), and this improved to strong correlation (0.645) when the 2-week time-shift was incorporated into the analysis. Both evaluations were statistically significant (P < 0.0001). The DRDN also moderately correlated (r = 0.412) with the number of COVID-19 deaths. Because death certification and hospital diagnosis may be delayed, real-time trend recognition in a pandemic may benefit from use of DRDN from MEO.

Shiga Toxin-Producing Escherichia coli in the Long-Term Survival Phase Exhibit Higher Chlorine Tolerance and Less Sublethal Injury Following Chlorine Treatment of Romaine Lettuce.

The extent of chlorine inactivation and sublethal injury of stationary-phase (STAT) and long-term survival-phase (LTS) cells of Shiga toxin-producing Escherichia coli (STEC) in vitro and in a lettuce postharvest wash model was investigated. Four STEC strains were cultured in tryptic soy broth supplemented with 0.6% (w/v) yeast extract (TSBYE; 35°C) for 24 h and 21 d to obtain STAT and LTS cells, respectively. Minimum bactericidal concentration (MBC) and dose-response assays were performed to determine chlorine's antibacterial efficacy against STAT and LTS cells. Chlorine solutions (pH 6.5) and romaine lettuce were each inoculated with STAT and LTS cells to obtain initial populations of ∼7.8 log colony-forming units (CFU)/mL. Survivors in chlorine solutions were determined after 30 s. Inoculated lettuce samples were held at 22°C ± 1°C for 2 h or 20 h and then exposed to chlorine (10-40 ppm) for 60 s. Survivors were enumerated on nonselective and selective agar media following incubation (35°C, 48 h). The MBC for STAT and LTS cells was 0.04 and 0.08 ppm, respectively. Following exposure (30 s) to chlorine at 2.5, 5.0, and 10 ppm, STAT cells were reduced to <1.0 log CFU/mL, whereas LTS survivors were at 5.10 (2.5 ppm), 3.71 (5.0 ppm), and 2.55 (10 ppm) log CFU/mL. At 20 and 40 ppm chlorine, greater log CFU reductions of STAT cells (1.64 and 1.85) were observed compared with LTS cells (0.94 and 0.83) after 2 h of cell contact with lettuce (p < 0.05), but not after 20 h. Sublethal injury in STEC after chlorine (40 ppm) treatment was lower in LTS compared with STAT survivors (p < 0.05). Compared with STAT cells, LTS cells of STEC seem to have higher chlorine tolerance as planktonic cells and as attached cells depending on cell contact time on lettuce. In addition, a higher percentage of LTS cells, compared with STAT cells, survive in a noninjured state after chlorine (40 ppm) treatment of lettuce.

Mindful awareness and resilience skills for adolescents (MARS-A): a mixed-methods study of a mindfulness-based intervention for a heterogeneous adolescent clinical population.

OBJECTIVES: Mindful Awareness and Resilience Skills for Adolescents (MARS-A) is a mindfulness-based intervention adapted for the adolescent population. While previous studies have explored the benefits of MARS-A in various single-diagnosis populations, the aim of this study was to assess MARS-A for a heterogenous clinical adolescent population with mental health and/or chronic diagnoses, focusing on the underlying suffering present in all these conditions rather than its effects on a single diagnosis itself. METHODS: Qualitative data was collected through interviews to understand post-intervention participant perspectives and experiences. Quantitative data was collected through measures to investigate preliminary secondary outcomes. RESULTS: After participating in MARS-A, participants reported qualitative benefits in enhanced well-being, including coping with difficult emotions and managing sleep and/or pain. Quantitative results showed a reduction in functional disability, psychological distress, perceived stress, and depressive symptoms; increase in positive affect; and benefit in coping with pain and chronic conditions. CONCLUSIONS: MARS-A shows great potential in a heterogeneous clinical adolescent population.

The Attenuation of Microbial Reduction in Blueberry Fruit Following UV-LED Treatment.

Ultraviolet-C (UV-C) irradiation is a well-recognized technology for improving blueberry postharvest quality, and previous literature indicates that it has the potential for dual-use as an antimicrobial intervention for this industry. However, the practicality and feasibility of deploying this technology in fresh blueberry fruit are significantly hindered by the shadowing effect occurring at the blossom-end scar of the fruit. The purpose of this study was to determine if treating the blueberry fruit within a chamber fitted with UV-Light Emitting Diodes (LEDs) emitting a peak UV-C at 275 nm could minimize this shadowing and result in improved treatment efficacy. Ten blueberry fruits were dip-inoculated with E. coli at a concentration of 105 CFU/mL and irradiated within the system at doses of 0, 1.617, 3.234, 9.702, and 16.17 mJ/cm2 (0, 30, 60, 180, and 300 s). Statistical analysis was performed to characterize the extent of microbial survival as well as the UV-C inactivation kinetics. A maximum of 0.91-0.95 log reduction was observed, which attenuated after 60 s of treatment. The microbial inactivation and survival were thus modeled using the Geeraerd-tail model in Microsoft Excel with the GInaFIt add-in (RMSE = 0.2862). Temperatures fluctuated between 23 ± 0.5°C and 39.5°C ± 0.5°C during treatment but did not statistically impact the treatment efficacy (P = 0.0823). The data indicate that the design of a UV-LED system may improve the antimicrobial efficacy of UV-C technology for the surface decontamination of irregularly shaped fruits, and that further optimization could facilitate its use in the industry.

Developing a Decision-making Tool for Agricultural Surface Water Decontamination Using Ultraviolet-C Light.

Ultraviolet-C (UV-C) light-assisted water treatment systems are an increasingly investigated alternative to chemical sanitizers for agricultural surface water decontamination. However, the relatively high concentration of particulate matter in surface water is a major challenge to expanding its application in the production of fresh produce. The objective of this project was to test the efficacy of two commercial UV-C devices to reduce the microbial risk of agricultural water in order to develop a web application to assist growers in decision-making related to the on-farm implementation of UV-C technologies for agricultural water treatment. An on-farm study using three agricultural water sources was performed to determine the microbial reduction efficacy of a low power, low flow (LP/LF; 1-9 gallons per minute (GPM), 1.34-gallon capacity) and a high powered, high flow (HP/HF; 1-110 GPM, 4.75-gallon capacity) device at flow rates of 6, 7, and 9 GPM. A threshold of 30% UVT for the HP/HF device was observed, wherein lower water transmissibility significantly impacted microbial inactivation. Although less effective at lower %UVT, the LP/LF device costs less to install, maintain, and operate. The observations were used to design an online tool for growers to calculate the predicted reduction of generic Escherichia coli using either device based on the %UVT of their water source. However, because this study utilized an exploratory and proof-of-concept approach, the experimental flow rates were limited to reflect the capacities of the smaller unit (9 GPM) for direct comparison to the larger unit. Thus, the preliminary model and tool are largely limited to the experimental conditions. Yet, these results of this study demonstrate the utility of UV-C light in reducing the microbial risk of agricultural water, and future studies using different UV-C devices and higher flow rates will expand the use of the decision-making tool.

A case study for local data surveillance in opioid overdose fatalities in Cuyahoga County, OH 2016-2020.

Introduction: Fentanyl and fentanyl analogs have increased the overdose mortality rates in the United States, significantly impacting states like Ohio. We examined carfentanil overdose deaths, other contributing Cause of Death (COD) drugs, and drug seizure trends from 2016 to 2020 in Northeast Ohio. Materials and methods: We studied death investigation data from the Cuyahoga County, Ohio Medical Examiner's Office (CCMEO) of all fatal accidental opioid overdoses as well as drug seizure data from Cuyahoga County Regional Forensic Science Laboratory (CCRFSL). We also compared decedents' race, gender, age, residential locality, drugs contributing to the COD in opioid cases, and for carfentanil, fentanyl, and cocaine seizures in Cuyahoga County from 2016 to 2020 (N = 2948). Results: Decedents' had an average of three different drugs contributing to their COD. A bimodal carfentanil spike was observed in fatal accidental overdoses in Cuyahoga County for the years 2017 and 2019. Decedents in urban residency, who were Non-Hispanic, White and younger, significantly predicted the presence of carfentanil contributing to the COD. In 2020, decedents who were Black and older were significantly associated with cocaine contributing to the COD. Carfentanil and carfentanil-related overdoses were significantly correlated. Discussion: The pervasiveness of illicitly manufactured fentanyl and fentanyl analog (e.g., carfentanil) mixtures with other drugs are changing the demographics of persons who fatally overdose in Cuyahoga County, OH. Significant trending shifts can also be observed for the presence of carfentanil in decedent and seizure county data. Conclusions: Local data of drug-related overdose deaths and drug seizures from a medical examiner's office and affiliated forensic laboratory lab can be used for timely public health surveillance, and informing prevention, and intervention at the county level.

The Potential for Cover Crops to Reduce the Load of Escherichia coli in Contaminated Agricultural Soil.

Cover crops are plants seeded before or after cash crops to improve soil health, reduce weed pressure, and prevent erosion. Cover crops also produce various antimicrobial secondary metabolites (i.e., glucosinolates, quercetin), yet the role of cover crops in moderating the population of human pathogens in the soil has rarely been investigated. This study aims to determine the antimicrobial capacity of three cover crop species to reduce the population of generic Escherichia coli (E. coli) in contaminated agricultural soil. Four-week-old mustard greens (Brassicajuncea), sunn hemp (Crotalaria juncea), and buckwheat (Fagopyrum esculentum) were mixed into autoclaved soil and inoculated with rifampicin-resistant generic E. coli to achieve a starting concentration of 5 log CFU/g. The surviving microbial populations on days 0, 4, 10, 15, 20, 30, and 40 were enumerated. All three cover crops significantly reduced the population of generic E. coli compared to the control (p < 0.0001), particularly between days 10 and to 30. Buckwheat resulted in the highest reduction (3.92 log CFU/g). An inhibitory effect (p < 0.0001) on microbial growth was also observed in soils containing mustard greens and sunn hemp. This study provides evidence for the bacteriostatic and bactericidal effect of particular cover crops. More research regarding the secondary metabolites produced by certain cover crops and their potential as a bio mitigation strategy to improve on-farm produce safety is warranted.

Protocol for Evaluating the Microbial Inactivation of Commercial UV Devices on Plastic Surfaces.

With the plethora of commercially available UV-C devices exhibiting different intensity and lifespans, it is critical to consumer safety that companies verify and clearly communicate the efficacy of their devices as per the intended use. The purpose of this study was to define a low-cost protocol for investigating the antimicrobial efficacy of commercial UV devices for industry use. The tested devices included: a wall-mounted unit (Device A), a troffer unit (Device B), and an induction lamp unit (Device C). The devices were installed within an enclosed tower to prevent the transmission of UV-C radiation outside of the testing area. The procedure details determining the devices' antimicrobial efficacy using plastic coupons inoculated with Escherichia coli or Staphylococcus aureus. The protocol includes suggested time-distance treatments according to the potential application of each device type and reports the results as log CFU/mL reduction or percent reduction.

Trends in opioid overdose fatalities in Cuyahoga County, Ohio: Multi-drug mixtures, the African-American community and carfentanil.

Background: Ohio's age-adjusted opioid overdose fatality rate is double the national average. In an ever-evolving epidemic, it is crucial to monitor trends to inform public health interventions. Methods: A retrospective study was conducted using the Medical Examiner's decedent case files for all accidental opioid-related adult overdose deaths in Cuyahoga County (Cleveland), Ohio in 2017. Characterization of trends was based on autopsy/toxicology and first responder reports, medical records and death scene investigations. Results: Of 543 accidental opioid-related adult overdose fatalities, 64.1% died from 3+ drugs. The most common cause of death (COD) drugs included fentanyl (63.4%), heroin (44.4%), cocaine (37.0%) and carfentanil (35.0%). There were four times as many African American decedents as two years prior. Three or more COD drugs was >50% more common in those with fentanyl (Prevalence Ratio (PR) = 1.56[1.34-1.70]; p<.001) or carfentanil (PR = 1.51[1.33-1.70]; p<.001) as a COD drug, more common with a history of prescription drug abuse (PR = 1.16[1.02-1.33]; p=.025), but less common in divorced/widowed decedents (PR = 0.83[0.71-0.97]; p=.022). Carfentanil was nearly 4 times as prevalent in those with previous illicit drug use (PR = 3.88[1.09-13.70]; p=.025), and less common in those with previous medical history (PR = 0.72[0.55-0.94]; p=.016) or age 50+ (PR = 0.72[0.53-0.97]; p=.031). Conclusions: Accidental opioid-related overdose fatalities in Cuyahoga County adults were dominated by 3+ COD drugs, with cocaine/fentanyl mixtures driving sharp increases in African American fatalities. Carfentanil was more prevalent in people fitting the profile of recreational drug use. This data can inform harm reduction interventions.

Feasibility of online mindfulness-based interventions for families affected with postpartum depression and anxiety: study protocol.

INTRODUCTION: Postpartum depression and anxiety (PPDA) is experienced by up to 20% of families in the first year. The condition impacts not only parents but also their developing child. While mindfulness-based interventions (MBI) have shown to be beneficial for this population, many parents do not have access to treatment or find it challenging to commit or complete the treatment. The COVID-19 pandemic has heightened some of the challenges that parents face. The ability to find time for needed self-care and health interventions is also affected by limited childcare support. The opportunity to attend a group online may significantly improve the accessibility to group MBI but may also bring challenges. This study aims to examine the feasibility and acceptability of online MBI groups for parents in families affected with PPDA. METHODS AND ANALYSIS: In this feasibility study, participants will include mothers diagnosed with PPDA and their partners. Two online MBI groups will run simultaneously for 8 weeks: one for mothers with PPDA and another one for their partners. The primary outcome will be feasibility of conducting the online groups, assessed from the facilitators' perspective, participants' perspective and attrition throughout the study. The participants' perspectives on feasibility will be assessed by questions including how difficult it was for them to make it to the sessions, specific obstacles encountered and their scheduling preferences. The facilitators' perspective will be assessed by frequency of technical difficulties encountered, of disruptions in the online sessions and of episodes where parents leave the screen (eg, to calm their child). Secondary outcomes will include mental health, couple relationship, satisfaction and acceptability which will also be evaluated through participant questionnaires. ETHICS AND DISSEMINATION: The study has received ethics approval from the University of British Columbia Children's and Women's Research Ethics Board. Study results will be disseminated through peer-reviewed journals and conferences. TRIAL REGISTRATION NUMBER: NCT04617132.

Escherichia coli Survival on Strawberries and Unpacked Romaine Lettuce Washed Using Contaminated Water.

A number of foodborne outbreaks have occurred in the past decade, with higher incidences associated with romaine lettuce and strawberries. Contaminated agricultural water has been reported as the source of microbial contamination in most of these outbreaks. Maintaining the adequate and sanitary quality (0 E. coli/100 mL) of agricultural water can be challenging during post-harvest operations such as washing. The study focused on the attachment of generic E. coli (Rifampicin resistant) onto romaine lettuce and strawberries, mimicking the produce wash step. The produce was washed with contaminated water, air-dried, and stored in display units for 7 days. The produce was sampled randomly each day and analyzed for the surviving E. coli count. The results indicated that E. coli can survive in both lettuce and strawberries over extended periods. A survival population of 2.3 log CFU/cm2 (day 8) was observed on lettuce with an initial population of 2.8 log CFU/cm2 (day 0). On strawberries, the population reduced from 3.0 (day 0) to 1.7 log CFU/cm2 (day 7), with an initial E. coli concentration of approx. 6 log CFU/mL in the wash water. Strawberry leaves had a higher attachment of E. coli than the fruit (p < 0.05). In conclusion, romaine lettuce and strawberries washed with contaminated water can cause an outbreak affecting consumers and public health.

Determining the Potential Food Safety Risks Associated with Dropped Produce on Floor Surfaces in Grocery Stores.

ABSTRACT: Grocery stores handle fresh produce in large quantities daily. According to the Food and Drug Administration Food Code, food is to be stored at least 15 cm above the floor, and all foods shall be protected from any source of contamination or otherwise discarded. It is reported in the literature that dropped produce could be a potential source of microbial contamination. Both consumers and employees often drop produce on the floor and then place it back into a display case or bin, which could potentially serve as a source of contamination. This study aims to determine the bacterial transfer rate on different produce types when dropped for various contact times onto floor surfaces contaminated with Listeria monocytogenes. Apples, peaches, and romaine lettuce were dropped separately onto carpet and tile surfaces from a distance of 1 m and held for 5 s, 1 min, 10 min, 1 h, and 4 h. Results showed that transfer from all produce types occurred from both the carpet (10.56%) and tile (3.65%) surfaces. Still, percent transfer was not statistically significant among different times used in this study (P > 0.05). Dropped romaine lettuce had the most transfer (28.97%) from both the surfaces combined, followed by apples (8.80%) and peaches (7.32%) with minimal transfer. Even with a low transfer level, grocery stores should include signage to alert consumers not to pick up dropped produce and should train their employees accordingly.

Genotypic and Phenotypic Characterization of Antimicrobial Resistance Profiles in Non-typhoidal Salmonella enterica Strains Isolated From Cambodian Informal Markets.

Non-typhoidal Salmonella enterica is a pathogen of global importance, particularly in low and middle-income countries (LMICs). The presence of antimicrobial resistant (AMR) strains in market environments poses a serious health threat to consumers. In this study we identified and characterized the genotypic and phenotypic AMR profiles of 81 environmental S. enterica strains isolated from samples from informal markets in Cambodia in 2018-2019. AMR genotypes were retrieved from the NCBI Pathogen Detection website (https://www.ncbi.nlm.nih.gov/pathogens/) and using ResFinder (https://cge.cbs.dtu.dk/services/) Salmonella pathogenicity islands (SPIs) were identified with SPIFinder (https://cge.cbs.dtu.dk/services/). Susceptibility testing was performed by broth microdilution according to the Clinical and Laboratory Standards Institute (CLSI) standard guidelines M100-S22 using the National Antimicrobial Resistance Monitoring System (NARMS) Sensititre Gram Negative plate. A total of 17 unique AMR genes were detected in 53% (43/81) of the isolates, including those encoding tetracycline, beta-lactam, sulfonamide, quinolone, aminoglycoside, phenicol, and trimethoprim resistance. A total of 10 SPIs (SPI-1, 3-5, 8, 9, 12-14, and centisome 63 [C63PI]) were detected in 59 isolates. C63PI, an iron transport system in SPI-1, was observed in 56% of the isolates (n = 46). SPI-1, SPI-4, and SPI-9 were present in 13, 2, and 5% of the isolates, respectively. The most common phenotypic resistances were observed to tetracycline (47%; n = 38), ampicillin (37%; n = 30), streptomycin (20%; n = 16), chloramphenicol (17%; n = 14), and trimethoprim-sulfamethoxazole (16%; n = 13). This study contributes to understanding the AMR genes present in S. enterica isolates from informal markets in Cambodia, as well as support domestic epidemiological investigations of multidrug resistance (MDR) profiles.

Ultraviolet inactivation of bacteria and model viruses in coconut water using a collimated beam system.

This study investigated the effect of ultraviolet-C irradiation on the inactivation of microorganisms in coconut water, a highly opaque liquid food (1.01 ± 0.018 absorption coefficient). Ultraviolet-C inactivation kinetics of two bacteriophages (MS2, T1UV) and three surrogate bacteria (Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes) in 0.1% (w/v) peptone and coconut water were investigated. Ultraviolet-C irradiation at 254 nm was applied to stirred samples, using a collimated beam device. A series of known ultraviolet-C doses (0-40 mJ cm-2) were applied for ultraviolet-C treatment except for MS2 where higher doses were delivered (100 mJ cm-2). Inactivation levels of all organisms were proportional to ultraviolet-C dose. At the highest dose of 40 mJ cm-2, three surrogates of pathogenic bacteria were inactivated by more than 5-log10 (p < 0.05) in 0.1% (w/v) peptone and coconut water. Results showed that ultraviolet-C irradiation effectively inactivated bacteriophage and surrogate bacteria in highly opaque coconut water. The log reduction kinetics of microorganisms followed log-linear and exponential models with higher R2 (>0.95) and low root mean square error values. The D10 values of 3, 5.48, and 4.58 mJ cm-2 were obtained from the inactivation of E. coli, S. Typhimurium, and L. monocytogenes, respectively. Models for predicting log reduction as a function of ultraviolet-C irradiation dose were found to be significant (p < 0.05). Fluid optics were the key controlling parameters for efficient microbial inactivation. Therefore, the ultraviolet-C dose must be calculated not only from the incident ultraviolet-C intensity but must also consider the attenuation in the samples. The results from this study imply that adequate log reduction of vegetative cells and model viruses is achievable in coconut water and suggested significant potential for ultraviolet-C treatment of other liquid foods.

UV-C Irradiation on the Quality of Green Tea: Effect on Catechins, Antioxidant Activity, and Cytotoxicity.

Short-wavelength ultraviolet (UV-C) irradiation is a nonthermal processing technique that is a possible alternative to the heat-pasteurization of tea beverages. This study investigated the effect of UV-C irradiation on the polyphenolic and total phenolic contents of a green tea beverage and analyzed cytotoxicity of irradiated green tea using a novel continuous flow-through UV system. UV-C fluence levels ranging from 0 to 240 mJ/cm2 were delivered to green tea, and polyphenols were chemically profiled. Continuous-flow UV-C irradiation of the green tea beverage at a fluence of 68 mJ/cm2  induced a minor reduction in the concentration of the most abundant catechin in green tea, (-)-epigallocatechin gallate (EGCG), from 145 to 131.1 µg/mL. The total phenolic content of the green tea beverage was 0.19 µg GAE/uL and remained constant at all UV fluence levels. The UV-treated green tea beverage showed no cytotoxic effects on normal intestinal cells with healthy colonic cells (CCD-18Co) maintained at 90% viability for the UV-treated green tea beverages and the control. The treated and nontreated green tea have comparable inhibitory effects on the survival of human colon cancer cells. Overall, these results demonstrate that the UV-C irradiation did not significantly deplete catechins or produce cytotoxic byproducts. PRACTICAL APPLICATION: Short wavelength ultraviolet (UV-C) irradiation is a nonthermal processing technique that is a possible alternative to the heat pasteurization of tea beverages. This study investigated the effect of UV-C irradiation on the antioxidant concentration of green tea and analyzed cytotoxicity of irradiated a green tea beverage using a novel continuous flow-through UV system. The results demonstrated that the UV-C irradiation did not significantly deplete catechins or produce cytotoxic byproducts.

Microbial inactivation and cytotoxicity evaluation of UV irradiated coconut water in a novel continuous flow spiral reactor.

A continuous-flow UV reactor operating at 254nm wave-length was used to investigate inactivation of microorganisms including bacteriophage in coconut water, a highly opaque liquid food. UV-C inactivation kinetics of two surrogate viruses (MS2, T1UV) and three bacteria (E. coli ATCC 25922, Salmonella Typhimurium ATCC 13311, Listeria monocytogenes ATCC 19115) in buffer and coconut water were investigated (D10 values ranging from 2.82 to 4.54mJ·cm-2). A series of known UV-C doses were delivered to the samples. Inactivation levels of all organisms were linearly proportional to UV-C dose (r2>0.97). At the highest dose of 30mJ·cm-2, the three pathogenic organisms were inactivated by >5 log10 (p<0.05). Results clearly demonstrated that UV-C irradiation effectively inactivated bacteriophage and pathogenic microbes in coconut water. The inactivation kinetics of microorganisms were best described by log linear model with a low root mean square error (RMSE) and high coefficient of determination (r2>0.97). Models for predicting log reduction as a function of UV-C irradiation dose were found to be significant (p<0.05) with low RMSE and high r2. The irradiated coconut water showed no cytotoxic effects on normal human intestinal cells and normal mouse liver cells. Overall, these results indicated that UV-C treatment did not generate cytotoxic compounds in the coconut water. This study clearly demonstrated that high levels of inactivation of pathogens can be achieved in coconut water, and suggested potential method for UV-C treatment of other liquid foods. INDUSTRIAL RELEVANCE: This research paper provides scientific evidence of the potential benefits of UV-C irradiation in inactivating bacterial and viral surrogates at commercially relevant doses of 0-120mJ·cm-2. The irradiated coconut water showed no cytotoxic effects on normal intestinal and healthy mice liver cells. UV-C irradiation is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier and safe food products. This study would provide technical support for commercialization of UV-C treatment of beverages.