Ensuring food safety modernization act produce safety rule compliance through water testing and sanitation validation programs

A large portion of fresh produce is consumed raw, and likewise, there have been many cases of foodborne illnesses associated with it. The contamination can occur at any point during the farm to fork continuum and may come from poor agricultural practices at the farm, deficit knowledge of food safety concerns among growers, and/or various physical, chemical, and biological hazards in the food supply chain. Agricultural water is a known vector for the transfer of foodborne pathogens onto fresh produce and has been implicated in recent foodborne outbreaks. Monitoring and management of microbial quality of agricultural water is a requirement under the Food Safety Modernization Act Produce Safety Rule (PSR). The water testing methods (n=9) mentioned in the PSR require no greater than a 6-hour time frame between the collection of the water sample and the initiation of analysis. This 6-hour timeframe is unrealistic for many farm locations in the Midwest. To address this issue, 103 agricultural water samples were collected from 60 different farms using method EPA 1603. A total of 31 samples were found contaminated with generic E. coli—mostly surface water (n=28, 87.5%). The results provide evidence that the sample-test time interval can be extended to a 24-hour time (p\u3e0.05), which makes quantitative generic E. coli testing more accessible to growers. Cross-contamination through agricultural water has led to foodborne outbreaks with produce as well. These bacteria generally grow in four growth stages of lag, log, stationary, and death; however, research reported the fifth phase following the death phase called long term survival (LTS) cells, which have a higher resistance to antimicrobial treatments. Their sensitivity to chemical sanitizers is unknown. The study focused on quantifying the resistance of stationary and LTS cells against chemical sanitizer treatment (chlorine, sodium hypochlorite) and determined the effects of bacterial growth phase against chlorine treatment. The results reported higher resistance to LTS cells in-vitro but statistically insignificant results in the lettuce wash model (p\u3e0.05). Monitoring the diverse routes of agricultural water contamination is critical to ensure the safety of fresh produce and to ensure that more intensive measures are required in the food supply chain to protect public health

Efficacy of ultraviolet (UV-C) light in reducing foodborne pathogens and model viruses in skim milk

The efficacy of low wavelength ultraviolet light (UV-C) as a disinfection process for a scattering fluid such as skim milk was investigated in this study. UV-C inactivation kinetics of two surrogate viruses (bacteriophages MS2 and T1UV) and three bacteria Escherichia coli ATCC 25922, S. Typhimurium ATCC 13311, Listeria monocytogenes ATCC 19115 in buffer and skim milk were investigated. UV-C irradiation was applied to stirred samples, using a collimated beam operating at 253.7 nm wavelength. A series of known UV-C doses (0–40 mJ·cm−2) were delivered to the samples except MS2 where higher doses (0–150 mJ·cm−2) were delivered. Biodosimetry, utilizing D values of viruses inactivated in buffer, was carried out to verify and calculate reduction equivalent dose. At the highest dose of 40 mJ·cm−2, the three pathogenic organisms were inactivated by more than 5 log10 (p \u3c .05). Results provide evidence that UV-C irradiation effectively inactivated bacteriophage and pathogenic microbes in skim milk. The inactivation kinetics of microorganisms was well described by log linear and exponential models with a low root mean squared error and high coefficient of determination (r2 \u3e 0.96). Models were validated and parameterized for predicting log reduction as a function of UV-C irradiation dose (p \u3c .05). This study clearly demonstrated that high levels of inactivation of pathogens can be achieved in skim milk, and suggests significant potential for UV-C treatment of treating fluids that exhibit significant scattering. Practical application This research paper provides scientific evidence of the potential use of UV technology in inactivating pathogenic bacteria and model viruses in skim milk. UV-C doses were validated and verified using biodosimetry. UV-C irradiation is an attractive food preservation technology and offers opportunities for dairy and food processing industries to meet the growing demand from consumers for safer food products. This study clearly shows the potential for using UV-C treatment for treating highly scattering fluid such as skim milk. Results from this work will be used to further develop continuous flow-through UV-C systems based on dean or turbulent flow patterns

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

A continuous-flow UV reactor operating at 254 nm 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 4.54 mJ·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 \u3e 0.97). At the highest dose of 30 mJ·cm− 2, the three pathogenic organisms were inactivated by \u3e 5 log10 (p \u3c 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 \u3e 0.97). Models for predicting log reduction as a function of UV-C irradiation dose were found to be significant (p \u3c 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 0–120 mJ·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

Application of Low Wave-length UV Irradiation to Inactivate Pathogenic Microbes in Highly Opaque Liquid Foods

UV-C irradiation is a novel non-thermal technology that is lethal to most of the pathogenic microbes in liquid foods. This study investigated the ability of UV-C irradiation to inactivate microorganisms including bacteriophage in coconut water, a highly opaque liquid food. UV-C inactivation kinetics of two surrogate viruses (MS2, T1UV) and three pathogenic bacteria ( E. coli ATCC 25922, Salmonella typhimurium ATCC 13311, Listeria monocytogenes ATCC 19115) in peptone and coconut water were investigated. UV-C irradiation was applied using a collimated beam and flow-through UV reactors operating at 253.7 nm wavelength. The optics (absorption and scattering coefficients) of the fluid are accounted for, and dose delivery is verified through bio-dosimetry, ensuring that target levels of disinfection are achieved, and allowing direct comparisons with other UV-C treatment. A series of known UV-C doses (0–40 mJ˙cm-2) were delivered to the samples in collimated beam and (0–30 mJ˙cm -2) for flow-through system, except MS2 where higher doses were delivered. All the three microbial pathogenic organisms were inactivated by more than 5 log10 (p \u3c 0.05) at highest doses of 40 and 30 mJ˙cm -2 using both reactors. The inactivation kinetics were best described by log linear and exponential models with a low root mean squared error (RMSE) and higher coefficient of determination (R2\u3e0.95). Models for predicting log reduction as a function of UV-C irradiation dose were found to be significant (p \u3c 0.05) with low standard error and high coefficients of determination (R2). This study clearly demonstrated that high levels of inactivation of pathogens can be achieved in coconut water, and suggested significant potential for UV-C treatment of other liquid foods. Therefore, UV-C irradiation could be used as a potential alternative to traditional thermal pasteurization for control of E. coli, L. monocytogenes and S. typhimurium populations to help ensure the safety of fresh coconut water. Further research is suggested to study the organoleptic and nutritional quality of the treated food samples to evaluate the consumer acceptance of the UV treated foods

Extending the Holding Time for Agricultural Water Testing EPA Method 1603 for Produce Growers

Agricultural water is a known vector for the transfer of foodborne pathogens onto fresh produce. Development of pre-harvest and post-harvest microbial profiles of agricultural water used by fresh produce growers, processors, and holdings is a requirement under the Food Safety Modernization Act Produce Safety Rule. One of the United States Environmental Protection Agency (US EPA) approved agricultural water testing methods is US EPA Method 1603, which requires no greater than a 6-h time frame between the collection of the water sample and initiation of analysis. This 6-h timeframe is unrealistic for many produce growers due to there being few laboratories certified to conduct testing and the geographic location of the farms. Agricultural water samples (n = 101) from well water and surface water were collected from 60 different farms to determine if holding samples for 24 h yielded significantly more generic Escherichia coli (E.coli) than 6 h using EPA 1603 method. A total of 32 samples were found contaminated with generic E. coli. Of these positive samples, surface water accounted for 87.5% of the samples (n = 28). There was no significant disparity between populations of generic E. coli at 6- and 24-h sample-test time interval (p > 0.05). These results provide evidence that the sample-test time interval can be extended to 24-h time, which makes quantitative generic E. coli testing for agricultural water as mandated by the FSMA Produce Safety Rule more accessible to growers