Ppm Chlorine Research Articles

Chlorine Levels in a Cistern-Based Water Distribution System in Rural Honduras

Background: In 2014, a gravity fed, cistern-based chlorination system was installed into the water distribution system in La Hicaca, a village in the Yoro Department of Honduras. The water distribution system consists of a large cistern that feeds water through pipes into private faucets in each household. Per report the chlorine tablets utilized by the system can be utilized for over a one year time span. In June 2015, a study by Cook J.A. et al determined that water chlorination decreased the fecal contamination in drinking water in La Hicaca. However, chlorine levels were not measured at that time. This study aims to find out whether or not chlorine is present in the drinking water at homes that are connected to the chlorine distribution system in La Hicaca. Methods & Materials: In June 2017, members from Virginia Commonwealth University's Global Health and Health Disparities Program (GH2DP) collected water samples from a convenience sampling of 25 of 75 homes in La Hicaca that should receive chlorine from the water distribution system. Samples were then measured to determine the level of chlorine in the drinking water at each home. Per community report the chlorination tablets had been replaced approximately 4 months prior to testing. Results: Twenty-eight percent (7/25) of households had very low levels of chlorine in the drinking water from their private faucets. Six of the homes had a chlorine level of 0.05 PPM and one home had a chlorine level of 0.1 PPM. When the chlorine data were placed onto a map of homes in La Hicaca we found that the six homes with 0.05 PPM of chlorine were clustered together. The one home that had a chlorine level of 0.1 PPM was separate from the other homes with chlorine. The water cistern was found to have 0 PPM of chlorine. Conclusion: We did not find chlorine in a majority of the homes sampled in La Hicaca or in the cistern. In homes where it was found, it was found at very low levels. Further studies are needed to determine the effectiveness of the chlorination distribution system at various time points post chlorine tablet installation.

Influence of Hot Chlorinated Water and Stabilizer Package on the Fatigue Crack Growth Resistance of Glass Fiber Reinforced Polyamide.

To assess the potential use of polyamide (PA) for solar-thermal systems applications, the effect of water with varying chlorine content on the fatigue crack growth (FCG) resistance of two PA formulations differing in their stabilizer packages was investigated at 80 °C. A commercial PA containing 30 wt % glass fibers and a standard stabilization package (PA-0) was used as the reference material. For the other formulation, the reference material PA-0 was compounded with two additional stabilizers (PA-S1). Keeping the specimen geometry and initial loading conditions the same, the total number of cycles to ultimate specimen failure was found to be reduced with an increase in chlorine content for both materials. As to the effect of the chlorine content on crack growth kinetics, the most pronounced effect in enhancing the crack growth rates or decreasing the FCG resistance was determined between 0 ppm and 1 ppm chlorine content. When comparing the relative change of FCG resistance in chlorinated water (10 ppm) to the FCG resistance in non-chlorinated water (0 ppm), the additional stabilization in the material PA-S1 appears beneficial over the stabilization in the reference material PA-0.

Inactivation of stress-resistant ascospores of Eurotiales by industrial sanitizers

Different fungi, including the genera Aspergillus (Neosartorya), Paecilomyces (Byssochlamys) and Talaromyces, produce (asco)spores that survive pasteurization treatments and are regarded as the most stress-resistant eukaryotic cells. The sensitivity of the ascospores to treatments with industrial sanitizers containing chlorine dioxide and iodine (iodophors) has never been assessed before. Ascospores of 4 species of Eurotiales were tested and showed clear variations in sensitivity. The most resilient species, T. macrosporus and Pae. variotii (=B. spectabilis) survive 75, but not 200 ppm chlorine dioxide solution treatments. These species were able to survive 75 ppm iodine solution treatments, but relatively low amounts of ascospores (100–1000 spores) could be inactivated after 16 h of treatment. Inactivated spores did not show any sign of germination after 7 days following treatment on growth medium. As judged by microscopy, iodine inactivation resulted in visibly distorted ascospores. For the interpretation of results, the state of dormancy or activation of ascospores is highly important.

Effects of sodium hypochlorite and peroxyacetic acid on the inactivation of murine norovirus-1 in Chinese cabbage and green onion

Chinese cabbage and green onion are important vegetables for a variety of foods in Korea. Because these vegetables are used after being briefly washed with water, the disinfecting washing needs to be applied to inactivate norovirus. We evaluate the effectiveness of sodium hypochlorite (NaOCl) and peroxyacetic acid (PAA) on inactivation of murine norovirus-1 (MNV-1) in Chinese cabbage and green onion. NaOCl treatment with 400 ppm chlorine decreased MNV-1 by more than 1 log10 in both samples. One minute treatment with PAA at 300 ppm reduced MNV-1 by approximately 1 log10 in Chinese cabbage and 1.2 log10 in green onion, respectively. When concentrations permissible for use on food-contact surfaces by Korea Ministry of Food and Drug Safety (MFDS) were used to disinfect the vegetables, 300 ppm of PAA was significantly (P < 0.05) more effective than 200 ppm of NaOCl. Although color was unchanged with higher concentrations of NaOCl and PAA, increasing the concentration of NaOCl gradually reduced hardness values and produced an unpleasant chlorinated-odor in Chinese cabbage stems. Overall, our study indicates that PAA treatment at 300 ppm for green onion or 500 ppm for Chinese cabbage is suitable for inactivating MNV-1, and does not adversely affect the food quality.

Bactericidal Efficacy of Food Additive-Grade Calcium Hydroxide Against Salmonella Infantis on Eggshells.

The bactericidal efficacy of food additive-grade calcium hydroxide [FdCa(OH)2] was evaluated for inactivation of Salmonella Infantis and Salmonella Enteritidis in liquid and Salmonella Infantis on contaminated eggshells. The activity of FdCa(OH)2 was also compared with that of sodium hypochlorite (NaOCl) containing 150 ppm chlorine (150 ppm NaOCl). FdCa(OH)2 solutions (0.1% and 0.2%) in the presence or absence of organic materials (5% calf serum [CS]) at pH 12.6 were used to inactivate Salmonella Infantis and Salmonella Enteritidis in a reaction tube or on eggshells artificially contaminated with Salmonella Infantis. Both 0.1% and 0.2% FdCa(OH)2 were capable of inactivating Salmonella Infantis and Salmonella Enteritidis in liquid at >3 log10 colony-forming units (CFU)/ml within 3 and 1 min of contact time, respectively, even in the presence of 5% CS. Additionally, 0.1% and 0.2% FdCa(OH)2 reduced bacterial levels on contaminated eggshells to >3 log10 CFU/ml, within 3 and 1 min, respectively, in the presence of 5% CS. Without CS, 0.1% and 0.2% FdCa(OH)2 could reduce bacteria on eggshells to >3 log10 CFU/ml within 1 min and 30 sec, respectively. In contrast, 150 ppm NaOCl solution could not inactivate bacteria on eggshells down to >3 log10 CFU/ml within 3 min contact time, either with or without CS, and no bacterial reduction was observed in redistilled water. The findings of the present study indicate that FdCa(OH)2 solution has high efficacy against foodborne bacteria and may be a good candidate for enhancement of biosecurity at farms and egg processing plants.

Efficacy of Chlorine, Chlorine Dioxide, and Peroxyacetic Acid in Reducing Salmonella Contamination in Wash Water and on Mangoes Under Simulated Mango Packinghouse Washing Operations

Salmonellosis associated with consumption of mangoes have been traced back to the use of contaminated wash water. This highlights the critical role of wash water disinfection in mango processing, affecting its quality, and safety. Moreover, steps unique to the post-harvest handling of mangoes also create a conducive environment for internalization of pathogens into the fruit pulp. Currently, no effective treatment exists to eliminate internalized pathogens from mangoes. Therefore, it is critical to prevent contamination on the fruit to avert pathogen internalization. So the present study evaluated the efficacy of chlorine (200 ppm), peroxyacetic acid (80 ppm) and chlorine dioxide (5 ppm) for reducing Salmonella populations on mangoes and in wash water under simulated mango packing house conditions. Nalidixic-acid resistant isolates of Salmonella Montevideo, S. Newport, S. Baildon, S. Braenderup and S. Poona were used in this study. Disinfectants were added to inoculated wash water (ca.7 log CFU/ml) and mangoes (var. Atualfo and Tommy Atkins) were washed under simulated dump tank wash (24°C for 2 min), hot water treatment (46°C for 75 and 110 min) and hydrocooling conditions (21°C for 30 min). Wash water and mangoes were collected at different times for microbiological analysis. Additionally, residual disinfectant concentration was monitored throughout the study. All the three disinfectant tested were effective in significantly reducing Salmonella populations in wash water and on mangoes during dump tank wash, hot water treatment and hydrocooling (p≤0.05). Specifically, no Salmonella was detected from samples treated with 200 ppm chlorine and 80 ppm PAA. On the other hand, Salmonella was consistently recovered from mango and water samples treated with chlorine dioxide (5 ppm). This reduced antimicrobial efficacy can be attributed to the sharp decline in residual chlorine dioxide concentrations in wash water. Further, reductions in residual chlorine and PAA concentrations were also observed over time. Therefore, to ensure the sustained antimicrobial activity of chlorine and PAA, it is critical to regularly monitor and replenish the disinfectant in wash water. However, given the laboratory scale of these experiments, further validation of these results on a commercial scale are warranted.

Production of clean oil with low levels of chlorine and olefins in a continuous two-stage pyrolysis of a mixture of waste low-density polyethylene and polyvinyl chloride

In this study, a continuous two-stage pyrolyzer consisting of an auger reactor and a fluidized bed reactor was applied to produce an oil with a low level of chlorine from a mixture of low density polyethylene and polyvinyl chloride waste. In the experiment, the auger reactor operated at 300–400 °C, thus releasing HCl prior to the main pyrolysis in the fluidized bed reactor. The auger reactor also played a role in elevating vibrational modes of molecules to promote the production of ethene, propene, and 1,3-butadiene. The yields of those monomers totaled 29 wt.%. Pyrolysis oils obtained from the fluidized bed reactor were enriched with aromatics up to 95 wt.%. Together with the two-stage pyrolyzer and a lime hot filter, a pyrolysis oil having only 9.25 ppm chlorine could be obtained. This value is the lowest ever reported. This study showed that a two-stage pyrolyzer together with a lime hot filter could produce a pyrolysis oil with a very low chlorine content. Further, this work implies that the production of valuable monomers from the pyrolysis of polyolefins can be enhanced when a two-stage pyrolyzer is applied.

Impact of antimicrobial wipes compared with hypochlorite solution on environmental surface contamination in a health care setting: A double-crossover study

Antimicrobial wipes are increasingly used in health care settings. This study evaluates, in a clinical setting, the efficacy of sporicidal wipes versus a cloth soaked in a 1,000 ppm chlorine solution. A double-crossover study was performed on 2 different surgical and cardiovascular wards in a 1,000-bed teaching hospital over 29 weeks. The intervention period that consisted of surface decontamination with the preimpregnated wipe or cloth soaked in chlorine followed a 5-week baseline assessment of microbial bioburden on surfaces. Environmental samples from 11 surfaces were analyzed weekly for their microbial content. A total of 1,566 environmental samples and 1,591 ATP swabs were analyzed during the trial. Overall, there were significant differences in the recovery of total aerobic bacteria (P < .001), total anaerobic bacteria (P < .001), and ATP measurement (P < .001) between wards and between the different parts of the crossover study. Generally, the use of wipes produced the largest reduction in the total aerobic and anaerobic counts when compared with the baseline data or the use of 1,000 ppm chlorine. Collectively, the introduction of training plus daily wipe disinfection significantly reduced multidrug-resistant organisms recovered from surfaces. Reversion to using 1,000 ppm chlorine resulted in the number of sites positive for multidrug-resistant organisms rising again. This double-crossover study is the first controlled field trial comparison of using preimpregnated wipes versus cotton cloth dipped into a bucket of hypochlorite to decrease surface microbial bioburden. The results demonstrate the superiority of the preimpregnated wipes in significantly decreasing microbial bioburden from high-touch surfaces.

Viable-but-Nonculturable Listeria monocytogenes and Salmonella enterica Serovar Thompson Induced by Chlorine Stress Remain Infectious.

ABSTRACTThe microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial food-borne pathogens are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses such as chlorine, which is commonly used for fresh produce decontamination. Here, complete VBNC induction of green fluorescent protein-tagged Listeria monocytogenes and Salmonella enterica serovar Thompson was achieved by exposure to 12 and 3 ppm chlorine, respectively. The pathogens were subjected to chlorine washing following incubation on spinach leaves. Culture data revealed that total viable L. monocytogenes and Salmonella Thompson populations became VBNC by 50 and 100 ppm chlorine, respectively, while enumeration by direct viable counting found that chlorine caused a <1-log reduction in viability. The pathogenicity of chlorine-induced VBNC L. monocytogenes and Salmonella Thompson was assessed by using Caenorhabditis elegans. Ingestion of VBNC pathogens by C. elegans resulted in a significant life span reduction (P = 0.0064 and P < 0.0001), and no significant difference between the life span reductions caused by the VBNC and culturable L. monocytogenes treatments was observed. L. monocytogenes was visualized beyond the nematode intestinal lumen, indicating resuscitation and cell invasion. These data emphasize the risk that VBNC food-borne pathogens could pose to public health should they continue to go undetected.

Antibacterial activity of acidified sodium benzoate against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in tryptic soy broth and on cherry tomatoes

Concerns about undesirable by-products from chlorine sanitation of fresh produce and the limited efficacy with the presence of organic matter, have led to studies on alternative washing solutions. The aim of this study was to evaluate the antibacterial activities of acidified sodium benzoate (NaB) solutions against Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes in growth medium and on cherry tomatoes. Experimentally, the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs, >3 Log reduction) of NaB against E. coli O157:H7 ATCC 43895, S. Enteritidis, and L. monocytogenes Scott A were determined at pH 7.0–4.0 using micro-broth dilution method and agar plating method, respectively. The reduction of the three bacteria in tryptic soy broth (TSB) by 500 and 1000 ppm NaB at pH 2.0, 2.5 and 3.0 for 30 min at 21 °C was compared. Residual bacterial cocktails inoculated on cherry tomatoes were determined after soaking in 3000 ppm NaB solution adjusted to pH 2.0 for 3 min at 21 °C. Results showed that the MBC of NaB reduced from >10,000 ppm at pH 7.0 to 1000 ppm at pH 4.0 and was identical for the three bacteria. The log reduction of bacteria in TSB indicated that 1000 ppm NaB at pH 2.0 was the most effective in killing the three pathogens. The respective reduction of E. coli O157:H7 and S. enterica cocktails inoculated on cherry tomatoes immersed in 3000 ppm NaB (pH 2.0) at 21 °C for 3 min was 4.99 ± 0.57 and 4.08 ± 0.65 log CFU/g, which was significantly higher (p < 0.05) than the treatments of 200 ppm free chlorine at pH 6.5. Conversely, the reduction of L. monocytogenes on tomatoes by 3000 ppm NaB (4.88 ± 0.73 log CFU/g) was similar (p > 0.05) to 200 ppm chlorine. Furthermore, the reduction of bacterial cocktails on tomatoes by 3000 ppm NaB at pH 2.0 was not affected after adding 1% tomato puree, and bacteria were not detected in NaB washing solutions with and without 1% tomato puree and on following un-inoculated tomatoes. This study showed that acidified NaB solution may be used as an alternative post-harvest wash of produce.

Evaluating the efficiency of chlorine removal from potable tap water using off-gassing, boiling, and filtration treatment methods

&#x0D; Background: One of the most frequent complaints to water distribution systems is the taste and odor of chlorine in consumer tap water. Chlorine is a common disinfectant used to inactivate and breakdown microbes and other contaminants. However, excess chlorine can result in an unpalatable chlorinous taste and odor. When water taste becomes too objectionable, consumers may search for alternative water sources, such as raw, untreated water that does not contain chemical additives. Raw, untreated water contains various contaminants, including disease-causing pathogens. To encourage consumers to drink treated tap water, and prevent disease, this study evaluated and compared the effectiveness of off-gassing, boiling and filtration as dechlorination methods for consumers to perform on their tap water. Method: Hach Method 8021 was performed to collect and analyse water samples following treatment with Off-gassing, Boiling and Filtration. Water samples were collected from BCIT SW1-1230. The Hach Pocket Colorimeter ™ II determined the free chlorine concentration of the water samples, and compared to a sample of untreated chlorinated tap water to see which method reduced chlorine concentrations the most. Results: Mean concentration of chlorine following off-gassing was determined to be 0.51 ppm, 0.24 ppm following boiling, and 0.55 ppm following filtration. It was determined that the boiling method was statistically significantly different from the mean values of chlorine concentration from the other two methods, as shown by the Kruskal-wallis test (P=0.000), and therefore was the most effective in dechlorinating tap water samples. This was further confirmed by the Scheffe’s Mutliple-Comparison Test and eyeball test. Conclusion: Based on the results, boiling water is the most effective method to dechlorinate potable tap water for consumer acceptability. The free chlorine levels found post-boiling were also found to be below the WHO’s threshold for tasting and smelling chlorine in drinking water (0.3 ppm), and above WHO’s minimum required 0.2 ppm chlorine residual. Therefore, drinking water following boiling will be safe for consumption, as well as free of chlorinous taste and smell. Public Health professionals can safely advise consumers of an effective method to encourage treated tap water consumption, and to discourage finding alternative water sources.&#x0D;

Chlorine-contaminated anode and cathode PEMFC-recovery perspective

Progressive thinking about future generation proton exchange membrane fuel cells (PEMFCs) leads us to cost-effective compact fuel cells operating with dry reactants using self-humidifying membranes. Presently, however, PEMFCs are limited by number of factors. One such factor is the reactant impurities present in the feed streams. Chlorine is one such impurity affecting both anode and cathode PEMFC adversely. Several studies have reported adverse impact of anionic chloride in PEMFCs but scarce or no literature is available on the effect of chlorine gas as such on PEMFCs. In the present work, we report for the first time to the best of our knowledge the adverse effects of chlorine when introduced on anode and cathode independently using a single-cell PEMFC. About 94% (anode) and 82% (cathode) loss in performance is observed at an operating voltage of 0.6 V after contamination with 100 ppm chlorine at the anode and cathode respectively. It is found that operating at higher current density plays a significant role in the PEMFC recovery process. The duration of recovery changes for anode-contaminated cell and cathode-contaminated cell, which is 2 and 4 h respectively. The protons on the anode side and the hydroxyl ion at the cathode side help in replacing the chloride species adsorbed on the platinum surface. The electrochemical impedance studies show an increase in the charge transfer resistance after cathode contamination, whereas in the case of anode contamination, the cell resistance increases while maintaining the same charge transfer resistance.

MODIFICATION OF THE RECOVERED LOW- GRADE FAT TO FORMULATE ECO-FRIENDLY LUBRICANT GREASE

This study presents utilization of the inedible by-product fat of the municipal massacres to formulate bio-based lubricant grease. Inedible animal fat of acceptable quality has been recovered through the wet rendering process. The recovered fat was sterilized and bleached using 200 ppm chlorine dioxide solutions. The acceptable saponification and iodine values of the fat emphasize that it can be used in the chemical industry as an oleochemical resource. The fat was fractionalized into two fractions; stearic and oleic. The lithium soap of the stearic fraction was employed as a thickener and the oleic fraction has been adapted for use as base oil, depending on its proportion of combination compared to the thickener. It was found that the ideal composition of the formulated bio-grease is 15-20 % thickener to 85-80 % base oil. The performance testing shows that the formulated grease has NGLI ranges between 2- 3. The grease can be utilized as a lubricant agent in machinery and gears with an acceptable lubricating performance.

Application of antimicrobial treatment to whole carcasses during prechill can improve microbial quality of broiler parts

AbstractBroilers cut up into parts have been reported to have higher microbial numbers than corresponding whole carcasses. Prechill immersion leads to water uptake by whole carcasses which is released during cut‐up. The objective of this study was to determine if an antimicrobial treatment applied during prechill can reduce the prevalence or numbers of total aerobic bacteria and Escherichia coli on corresponding chicken parts. Commercially eviscerated broiler carcasses were subjected to sequential immersion prechill, final ice water chill, and cut‐up procedures. Enumeration of total aerobic bacteria, coliforms, and E. coli was performed using carcass rinses at postevisceration, after 15 min prechill (22–25°C water), after 30 min ice water immersion chill (0–4°C water), and following cut‐up into parts. Six prechill, antimicrobial treatments were evaluated: 50 ppm chlorine, 50 ppm chlorine + 0.5% T‐128 (a chlorine stabilizer), 20 ppm peracetic acid, 20 ppm peracetic acid + 0.5% T‐128, 0.5% T‐128, and water. Addition of 0.5% T‐128 to water, 20 ppm peracetic acid, or 50 ppm chlorine during prechill significantly (p &lt; .05) decreased total aerobic bacteria and E. coli/coliforms following prechill by ∼1.5–2.0 log compared to the water control.Practical applicationsAntimicrobial treatment of whole broiler carcasses during prechill is a practical means to lessen microbial contamination of corresponding broiler parts. Chlorine and peracetic acid applied with a chlorine stabilizer (T‐128) can be expected to be effective for this purpose.

Outgraded produce variably retains surface inoculated Escherichia coli through washing

The use of secondary quality produce has gained attention as a solution to food waste in both the U.S. and Europe. The purpose of this study was to evaluate the impact of using secondary quality or outgraded produce on the retention of surface inoculated E. coli following a rinse treatment on four model fresh produce systems (apple, tomato, carrot, lettuce). A three-strain cocktail of rifampicin-resistant generic E. coli, with a concentration of 9.0 log CFU/mL, was spot-inoculated on the intact surfaces of U.S. No.1 grade produce items and damaged or decayed areas of outgraded produce items. Generally, outgraded produce of all four kinds retained higher levels of inoculated E. coli following two postharvest treatments, chlorinated (150 ppm) or water only. However, physical damage, those defects which compromised the integrity of the produce surface, lead to significantly greater E. coli levels following rinsing than did physiological defects. Compared to U.S. No.1 quality apples, outgraded apples retained 4.3 ± 1.4 log CFU/g more E. coli following water only treatment, and 3.6 ± 1.7 log CFU/g more following chlorine treatment. Outgraded tomatoes retained significantly more (3.5 ± 1.1 log CFU/g) inoculated E. coli following water only rinse and 3.0 ± 1.4 log CFU/g more inoculated E. coli following chlorine treatment than U.S. No.1 quality tomatoes did under the same treatment conditions. Outgraded carrots retained 1 ± 1.1 log more CFU/g inoculated E. coli following water only treatment and 0.5 ± 0.8 log more CFU/g inoculated E. coli following chlorine treatment, compared to U.S. No.1 carrots. Outgraded lettuce leaves retained 1.6 ± 0.5 log CFU/g more inoculated E. coli following water only treatment and 4.1 ± 0.4 log CFU/g more inoculated E. coli following chlorine treatment than did U.S. No.1 quality lettuce leaves under the same treatment conditions. Treating with 150 ppm chlorine was not sufficient to eliminate the increased microbial retention associated with secondary quality or outgraded produce, and the efficacy of disinfection was greatly affected by type of defect. Apples with physical damage retained significantly higher E. coli loads than did those with physiological defects, an additional 2.6 log CFU/g under chlorine treatment and 0.8 log CFU/g more under was water only treatment. Tomatoes with physical damage had a 1.3-log CFU/g and 0.6-log CFU/g average increase of retained E. coli counts compared to those with physiological defects following a chlorine and water only treatment, respectively. Although a chlorine dip provided only a modest reduction in pathogens, generally, outgraded produce with physiological defects may present less food safety risks if introduced into the fresh market than does produce with physical damage due to their enhanced retention of bacterial cells. Therefore, as industry considers how to minimize its food waste problem, preferentially directing physically damaged produce away from the fresh market will help to minimize risk while maximizing food resources.

Study and Characterization of LLDPE/Polyolefin Elastomer and LLDPE/EPDM Blend: Effect of Chlorinated Water on Blend Performance

The objective of this study was to investigate the effects of two elastomers, namely ethylene butene copolymer (EBC) and ethylene propylene diene monomer (EPDM), on the physical, thermal and morphological properties of blend after exposure to chlorine. Blends of linear low-density polyethylene (LLDPE), ethylene-butene copolymers (EBC) and ethylene propylene diene ter polymer (EPDM) with different content were prepared by melt mixing in a twin-screw extruder. The LLDPE blend with EBC and EPDM were tested with water containing 50 ppm and 5000 ppm chlorine under static condition for 500 hr at 25°C and 80°C. Highest weight gain was observed for a higher concentration of chlorine for LLDPE/EBC-55 and LLDPE/EPDM-37 blend. It is seen that at 50 ppm chlorine concentration, the mechanical properties of LLDPE, LLDPE/EBC blend and LLDPE/EPDM blend remain unchanged. Chemical changes in the aged sample were checked by Infrared spectroscopy (FTIR), where increase in the O-H and C=O infrared bands was observed. The thermal characteristics of LLDPE, LLDPE/EBC blend, and LLDPE/EPDM blends were investigated using DSC and TGA which shows melting temperature and crystalline melt temperature remains unchanged while percent crystallinity was increased by 10 percent for LLDPE. Scanning electron microscope (SEM) showed that there was no formation of the micro cracks and cavities of LLDPE/EBC 73 blend and LLDPE/EPDM 73 blend after exposure to a higher concentration of chlorine. It indicated the excellent stability of prepared blend against chlorinated water

Efficacy of chlorine as a disinfecting agent on produce-harvesting gloves contaminated with Escherichia coli O157:H7 or Salmonella

To minimize pathogen transfer from field worker's hands during hand harvest of ready-to-eat produce, gloves are often worn. However, fields are not sterile environments and transfer of pathogens to the gloves could occur throughout the day if the gloves come into contact with contaminated materials such as soil and produce. Given that changing gloves repeatedly is a costly solution, the merits to disinfecting gloves with chlorine solutions in the field were explored with efficacy (percent prevalence of gloves that were negative or positive for the pathogen) evaluated by subjecting the treated gloves to enrichment culture. Both the glove's level of pathogen contamination and chlorine exposure concentration affected the efficacy (P = 0.0000 and 0.0025, respectively). For example, complete elimination of Salmonella inoculated at ca. 3 log CFU/nitrile glove piece occurred at 50 ppm chlorine. However, when glove pieces had initial levels of ca. 6 log CFU E. coli O157:H7, exposure to 175 ppm did not completely eliminate the pathogen. Moreover, the likelihood of E. coli O157:H7 and Salmonella surviving were 32.0 and 4.4 times greater when the pathogen had been cultured on solid agar versus in liquid broth (95% CIs: 10.9 to 94.3 [P = 0.0000] and 2.1 to 8.9 [P = 0.0000], respectively). Another observation of this study was that dirty gloves exposed to both soil and lettuce sap were 11.6 times more likely than clean gloves to have the pathogen present after chlorine treatment (95% CI: 3.4 to 39.2, P = 0.0000). Monitoring these wash solutions for active chlorine revealed that no more than a 50% drop occurred suggesting that sufficient active chlorine remained for inactivating suspended pathogens and preventing cross-contamination. This data together with the observation that washing gloves in a second fresh batch of chlorine had little effect on the number of gloves absent of contamination would suggest that soil and sap is likely serving to protect the pathogen from exposure to the chlorine disinfectant. In an attempt to remove these materials, scrubbing during the chlorine immersion did not affect the efficacy of contaminated nitrile gloves (P = 0.1054) and actually led to a decreased efficacy of the chlorine treatment on contaminated Canners gloves (P = 0.0308). Although Salmonella and E. coli O157:H7 residing on nitrile and Canners gloves that survived exposure to 200 ppm chlorine could be transferred to produce handled by the treated gloves, frequent washing of gloves with chlorine could be an effective risk reduction strategy as they would reduce the numbers of gloves that may be contaminated with low levels of pathogens.

Effect of modified atmosphere packaging on preserving various types of fresh produce

AbstractModified atmosphere packaging (MAP) is an effective preservation method for extending the shelf‐life of various foods. This study was conducted to investigate the applicability of MAP for improving the food quality and safety of various fresh produce during refrigeration storage. Thirteen kinds of fresh produce were washed with 100 ppm chlorine and then packaged in three different types of packaging film using two different methods (air and 100% CO2 gas). Changes of the headspace gas composition, visual quality, microbial populations, and electrolyte leakage of the packaged samples were measured during storage at 4 ± 2 °C. MAP using CO2 gas resulted in lower levels of total mesophilic bacteria, Escherichia coli/coliform, and yeast/mold in the fresh produce compared than the air packaging. In particular, MAP using CO2 gas was effective at maintaining low levels of yeast and mold on grapes, soybean sprouts, and lotus roots during storage (p ≤ .05). However, the visual quality of some of the fresh produce (e.g., green vegetables) during storage was affected by MAP. Higher levels of electrolyte leakage were observed in fresh produce packaged under CO2 gas than that under air, except for grapes and lotus roots.Practical applicationsThese results suggest that although MAP may be useful for improving the shelf‐life of some root vegetables and fruits during storage, its application would be limited for certain types of fresh produce because of quality deterioration. The result of this study could be used for developing the effective preservation method for fresh produce.

Study and characterization of LDPE/Polyolefin elastomer and LDPE/EPDM blend: effect of chlorinated water on blend performance

The free chlorine present in water which is used as a disinfectant is reported to reduce the life of the polymeric material. The objective of this work is to study the influence of chlorine concentration on low-density polyethylene (LDPE) and blends of LDPE with ethylene butene copolymer (EBC) and ethylene propylene diene terpolymer (EPDM). The LDPE blend with EBC and EPDM were tested with water containing 50, 500, and 5000 ppm chlorine under static condition for 500 h at 25 and 80 °C. It has been seen that at 5000 ppm chlorine concentration, the mechanical properties of LDPE, LDPE/EBC blend, and LDPE/EPDM blend changed drastically and a significant reduction in the elongation at break was found for LDPE, LDPE/EBC, and LDPE/EPDM blend. LDPE/EPDM shows stable modulus value for 5000 ppm as 80 °C. Chemical changes in the aged sample were studied by Fourier transform infrared spectroscopy (FTIR) where an increase in the O–H and C=O peaks were observed. The thermal characteristics of LDPE, LDPE/EBC blend, and LDPE/EPDM blends were investigated using DSC and TGA which shows that the melting temperature and crystalline melt temperature remains unchanged while percent crystallinity increases slightly. Scanning electron microscope showed that there was the formation of microcracks and cavities on the fracture surface of LDPE, LDPE/EBC blend, and LDPE/EPDM blend after exposure to a higher concentration of chlorine indicative of degradation. Furthermore, the Chlorine resistance of LDPE/EPDM blend at 5000 ppm chlorine concentration is much higher than that of pristine LDPE.

Resistance ofStaphylococcus aureuson food contact surfaces with different surface characteristics to chemical sanitizers

AbstractOne of the factors contributing to foodborne illnesses is improper cleaning and sanitization of food contact surfaces. This study aimed to investigate the influence of various factors onStaphylococcus aureusattachment and biofilm formation on food contact materials and to determine sanitizing efficacy. The factors examined were contact materials (stainless steel, SUS; glass, GL; polypropylene, PP; and polyethylene, PE), surface conditions (smooth vs. scratched and with vs. without biofilms), and chemical sanitizers (70% ethanol and 200 ppm chlorine). Sanitization more efficiently loweredS. aureuscounts on SUS and GL than on PP and PE. Sanitization efficacy of ethanol was better than that of chlorine. Surfaces with scratches and biofilms were the most resistant to sanitization methods. The use of low‐adherent materials in food facilities, the selection of effective sanitizing methods, and the application of proper cleaning and disinfection procedures for food contact surfaces are essential for ensuring food safety.Practical applicationsControl ofS. aureuson food contact surface is important to reduce cross‐contamination in the foodservice industry. Hydrophobic and rough food contact surfaces promoteS. aureusadherence and biofilm formation. Ethanol can be an effective chemical sanitizer againstS. aureusbiofilm, regardless of the material or roughness of the food contact surfaces. The use of hydrophilic materials, frequent replacement of equipment, and selection of proper sanitizing methods are recommended to prevent foodborne illnesses.