Detection of Salmonella typhimurium Grown Directly on Tomato Surface Using Phage-Based Magnetoelastic Biosensors

A phage-based magnetoelastic (ME) biosensor method is being developed for on-site pathogen detection in fresh fruits and vegetables. Salmonella typhimurium was directly grown with minimal nutrients on tomato surfaces in order to mimic natural environmental conditions. S. typhimurium was inoculated on the surface of fresh tomatoes, and ME biosensors were used to detect the bacteria. The populations of S. typhimurium after 24-h incubation time at 37°C and 100% relative humidity were 6.1 and 7.8 logCFU/cm² after starting with initial inoculations of 3.0 and 5.0 logCFU/cm², respectively. After evident growth, measurement sensors with E2 phage immobilized on their surfaces and control sensors devoid of E2 phage were placed on the inoculated tomato surfaces and the resonant frequency shifts were measured. As the population of S. typhimurium increased, the resonant frequency shifts of the measurement sensors significantly increased (P?<?0.01), exhibiting 6,680?±?665 and 9,384?±?457 Hz for the populations of 6.1 and 7.8 logCFU/cm², respectively. SEM images confirmed that the measurement sensor resonant frequency shifts were due to S. typhimurium binding with E2 phage. This study demonstrated that the ME biosensor method could detect S. typhimurium grown directly on tomato surfaces with limited sample preparation procedures. Therefore, the ME biosensor could be applied as a cost and time effective, relatively simple, practically suitable on-site detection method for S. typhimurium in fresh produce.     

Development of oscillation method for reducing foodborne pathogens on lettuce and spinach

In this study, the efficacy of an oscillator for reducing the numbers of foodborne pathogens on lettuce and spinach was tested. A cocktail of three strains each of Salmonella typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes cells and of Bacillus cereus spores was inoculated onto lettuce and spinach leaves and followed by oscillation at 10 Hz and 20 Hz for up to 30 s. After treatment of inoculated lettuce leaf with an oscillator at 20 Hz for 30 s, 2.58, 2.82, 2.21 and 2.22 Log₁₀ CFU/g reductions were obtained with the cells of S. typhimurium, E. coli O157:H7 and L. monocytogenes and the spores of B. cereus, respectively. In the case of the oscillation treatment of spinach leaf, 2.89, 3.73, 2.46 and 2.25 Log₁₀ CFU/g reductions of those pathogens were achieved under the same condition. Statistically significant reductions were observed after oscillation treatment at 20 Hz for 5-10 s. The oscillation treatment at 10 Hz led to slightly less reductions of the pathogens tested as compared to the treatment at 20 Hz. In conclusion, the oscillation method developed shows to be highly efficacious in reducing foodborne pathogens on lettuce and spinach leaves.     

Inactivation of Salmonella typhimurium by high pressure carbon dioxide

Thermal inactivation of Salmonella typhimurium was studied under CO₂pressures of 15, 30 and 60 atm at 25, 35 and 45°C. Two phases were observed in the destruction curves. The earlier stage was characterized by a slow rate of inactivation in the number of S. typhimurium, which increased sharply at the later stage. It was suggested that the cell death resulted from the lowered pH due to solubilization of CO₂. An increase of pressure and/or temperature enhanced the antimicrobial effects of CO₂. Salmonella typhimurium suspended in physiological saline (PS) was completely inactivated under 60 atm CO₂treatment in 35 and 15 min at 25 and 35°C, respectively. On the other hand, it was completely inactivated when suspended in PS containing brain–heart infusion broth for 140 and 100 min. A minimum D -value was obtained under 60 atm CO₂pressure at 45°C. Inactivation rates of S. typhimurium were sensitive to pressure, temperature, exposure time, initial number of cells, and the suspending medium.     

An apparatus for studying the effect of transient temperature on growth of bacteria in a gel matrix

Apparatus was constructed to subject colonies of bacteria, formed from single cells immobilized in solidified culture media contained between sheets of polymer, film to time-varying temperatures in the range 2–80°C with rates of change of 1°C s⁻¹. Results for the growth ofSalmonella typhimuriumLT2 in medium solidified with gelatin under sinusoidally-varying temperatures between 12 and 22°C and of period 12 or 22 min are presented and were predictable by time–temperature integration using isothermal growth rates.odi     

A Novel Colorimetric Detection of <Emphasis Type="Italic">S. typhimurium</Emphasis> Based on Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Magnetic Nanoparticles and Gold Nanoparticles

Salmonella typhimurium is one of the most common causes of food-associated disease. A colorimetric nanosensor was developed to detect S. typhimurium which was based on the gold nanoparticles’ (GNPs) color change effect. Fe₃O₄ magnetic nanoparticles (MNPs) and GNPs were synthesized separately. Two complementary sequences of the S. typhimurium target DNA were combined to Fe₃O₄ MNPs and GNPs to fabricate capture probes and signal probes. Fe₃O₄ MNPs could achieve the rapid separation and enrichment of target DNA. With the addition of S. typhimurium target DNA sequences, the sandwich-like structures were formed via the DNA hybridization recognition effect. The original good dispersion of GNPs was broken. GNPs showed different degrees of aggregation with different amount of S. typhimurium target DNA. The color changed from red, purple to blue which could be characterized by UV-Vis spectrophotometer. The absorbance spectra of GNPs red shifted constantly with the intensity ratio of A700/A521 changed regularly. There was a linear correlation between the ratio of A700/A521 and the amount of S. typhimurium target DNA. Thus, this was calculated for the basis of quantitative detection of S. typhimurium. This method is simple and rapid with high sensitivity and specificity which could be used to detect actual samples.     

Contamination on fresh vegetables during cultivation and marketing

A total of 345 samples of vegetable from farms, a wholesale market, supermarkets and small shops in Granada were examined between February, 1981 and March, 1983. The vegetables consisted of the green leaves of beet, artichoke, cerely, cardoon, escarole, cabbage, Brussels sprouts, cauliflower, endive, asparagus, spinach, lettuce and parsley. The results obtained indicated a high degree of faecal contamination. Escherichia coli was detected in 86.1% of the samples, and salmonellae were isolated from 7.5%. The serotype most frequently isolated was Salmonella typhimurium.     

Antioxidant properties and mutagenicity of Pinus morrisonicola and its vinegar preparation

Pine (Pinus morrisonicola Hayata) needles was tested for toxicity and mutagenicity by Ames test and reducing power and scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals. Based on the tests on Salmonella typhimurium TA97 and TA100, P. morrisonicola extract was not toxic and mutagenic. The reducing powers of P. morrisonicola extract and ascorbic acid were comparable with both effective concentration (EC₅₀) values being 0.06 mg/mL. The extract was more effective in scavenging ability and EC₅₀ values were 0.02 and 0.04 mg/mL for P. morrisonicola extract and ascorbic acid, respectively. With P. morrisonicola powder (50 mg/mL) added to the cultured saccharified broth at day 1, the wine with an ethanol content of 8.23% was produced at day 12. After 11 days of fermentation, the vinegar was obtained with an acidity of 5.21 g/100 mL. Accordingly, P. morrisonicola could be used in the development of alcoholic and vinegar products to provide its beneficial health effects.     

Factors affecting radiation D-values (D₁₀) of an Escherichia coli cocktail and Salmonella Typhimurium LT2 inoculated in fresh produce

Abstract: This study evaluated the effect of produce type, resuspension medium, dose uniformity ratio (DUR), and sample preparation conditions (tissue exposure, MAP, anoxia) on the D₁₀‐value of an Escherichia coli cocktail (BAA‐1427, BAA‐1428, and BAA‐1430) and Salmonella Typhimurium LT2 inoculated on the surfaces of tomato, cantaloupe, romaine lettuce, and baby spinach. Produce at room temperature were irradiated using a 1.35 MeV Van de Graaf electron beam accelerator at 0.2 to 0.9 kGy. The D₁₀‐values for E. coli and Salmonella were 0.20 ± 0.01 kGy and 0.14 ± 0.01 kGy, respectively. Bacterial inactivation was not affected by produce type as long as the samples were irradiated in unsealed bags, the bacteria were suspended in broth, and the sample tissue was exposed. Sample location in front of the e‐beam source during exposure is crucial. A 20% increase in DUR yielded a 53% change in the D_10‐values. Variations in sample preparation, microbiological methods and irradiation set‐up, result in variable D₁₀‐values for different microorganisms on fresh produce. Practical Applications: Most irradiation studies disregard the effect of sample handling and processing parameters on the determination of the D₁₀‐value of different microorganisms in fresh and fresh‐cut produce. This study shows the importance of exposure of sample, resuspension medium, available oxygen, and dose uniformity ratio. D₁₀‐values can differ by 35% to 53% based on these factors, leading to considerable under‐ or over‐estimation of the irradiation treatment. Results from this study will help to lay firm groundwork for future studies on D₁₀‐values determination for different pathogens on fruits and vegetables.     

The effect of oregano essential oil on survival/death of Salmonella typhimurium in meat stored at 5°C under aerobic,VP/MAP conditions

The effect of oregano essential oil and film permeability on the behaviour of Salmonella typhimurium in sterile and naturally contaminated beef fillets stored under aerobic, modified atmosphere consisting of 40% CO₂ /30% O₂ /30% N₂ (MAP) and a vacuum packaged (VP) environment was studied during storage at 5°C. In samples without oregano essential oil, the pathogen survived under all storage conditions. Addition of oregano essential oil at a concentration of 0·8% v/w resulted in an initial reduction of 1–2 log₁₀ cfu g⁻¹ of the majority of the microbial population of meat with lactic acid bacteria and S. typhimurium showing the greatest reductions in all gaseous environments regardless of film permeability. The use of VP/MAP at chill temperatures in conjunction with oregano essential oil as a means of controlling spoilage and safety of meat is discussed.     

Investigation of a large gap cold plasma reactor for continuous in-package decontamination of fresh strawberries and spinach

The aim of this work was to investigate the efficacy of a large gap atmospheric cold plasma (ACP) generated with an open-air high-voltage dielectric barrier discharge (DBD) pilot-scale reactor, operated in either static (batch) or continuous mode for produce decontamination and quality retention. Significant reductions in the bacterial populations inoculated on the strawberries and spinach were obtained after the static mode of ACP treatment with 2.0 and 2.2 log₁₀ CFU/ml reductions for E. coli and 1.3 and 1.7 log₁₀ CFU/ml reductions for L. innocua, respectively. Continuous treatment was effective against L. innocua inoculated on strawberries, with 3.8 log₁₀ CFU/ml reductions achieved. No significant differences in colour, firmness, pH or total soluble solids (TSS) was observed between control and ACP-treated samples with the effects of treatment retained during the shelf-life period. The pilot-scale atmospheric air plasma reactor retained the strawberry quality characteristics in tandem with useful antimicrobial efficacy.Industrial relevanceThis in-package plasma technology approach is a low-power, water-free, non-thermal, post-package treatment. Generating cold plasma discharges inside food packages achieved useful antimicrobial effects on fresh produce. Depending on the bacterial type, produce and mode of ACP treatment significant reductions in the populations of pathogenic microorganisms attached to the fresh produce was achieved within 2.5 min of treatment. The principal technical advantages include contaminant control, quality retention, mitigation of re-contamination and crucially the retention of bactericidal reactive gas molecules in the food package volume, which then revert back to the original gas.     

A comparative study on the effectiveness of chlorine dioxide gas, ozone gas and e-beam irradiation treatments for inactivation of pathogens inoculated onto tomato, cantaloupe and lettuce seeds

The increase in reported food-borne outbreaks linked with consumption of raw fruits and vegetables has motivated new research focusing on prevention of pre-harvest produce contamination. This study evaluates and compares the effectiveness of three non-thermal technologies, chlorine dioxide gas, ozone gas and e-beam irradiation, for inactivation of Salmonella enterica and Escherichia coli O157:H7 on pre-inoculated tomato, lettuce and cantaloupe seeds, and also their corresponding effect on seeds germination percentage after treatments. Samples were treated with 10 mg/l ClO₂ gas for 3 min at 75% relative humidity, with 4.3 mg/l ozone gas for 5 min and with a dose of 7 kGy electron beam for 1 min. Initial load of pathogenic bacteria on seeds was ~ 6 log CFU/g. Results demonstrate that all treatments significantly reduce the initial load of pathogenic bacteria on seeds (p < 0.05). In particular, after ozone gas treatments 4 log CFU/g reduction was always observed, despite the seeds and/or microorganisms treated. ClO₂ and e-beam treatments were noticeably more effective against Salmonella on contaminated tomato seeds, where 5.3 and 4.4 log CFU/g reduction were respectively observed. Germination percentage was not affected, except for cantaloupe seeds, where the ratio was significantly lowered after ClO₂ treatments. Overall, the results obtained show the great applicability of these non-thermal inactivation techniques to control and reduce pathogenic bacteria contamination of seeds.     

Antimutagenic and antimicrobial activities of pu-erh tea

The biological action of water extract of pu-erh tea (WEPT) was evaluated by Salmonella mutagenesis assay and bacteria test. Like green tea, oolong tea and black tea, WEPT showed neither cytotoxicity and nor mutagenicity toward Salmonella typhimurium TA98 and TA100 with or without S9 mix (an external metabolic activation system). WEPT at 0.5-5 mg/plate expressed a dose-dependent inhibitory effect against both the mutagenicity of aflatoxin B₁ (AFB₁), an indirect mutagen which requires metabolic activation, and 4-nitroquinoline-N-oxide (NQNO), a direct mutagen, in Salmonella typhimurium TA98 and TA100. In general, the antimutagenic activity of WEPT against AFB₁ and NQNO was weaker than other tea extract because of the least amount of total catechin in WEPT. For antimicrobial action, WEPT, green tea, oolong tea and black tea at 2.0 mg/ml showed inhibitory effect on growth of Staphylococcus aureus and Bacillus subtilis, but no effect on Escherchia coli. Obviously, WEPT has potential antimicrobial effect on gram-positive Staphylcoccus aureus and B. subtilis than that of gram-negative E. coli. In addition, caffeine and epicatechin (EC), main polyphenolic compounds in WEPT, showed both antimutagenic and antimicrobial effect against strains mentioned above, which may partially account for the antimutagenic and antimicrobial action of pu-erh tea.     

Modeling inactivation kinetics of food borne pathogens at a constant temperature

Four food borne pathogens (Listeria monocytogenes CA and Ohio₂, Salmonella enteritidis FDA and Salmonella typhimurium E21274, Escherichia coli O157:H7 931 and 933, Staphylococcus aureus 485 and 765) were inactivated under mild temperature (60 °C) and their survival curves determined at selected time intervals. Tailing was observed in all survival curves as a monotonic upward concavity. The resulting survival curves were either described by the Weibull or traditional first-order model and goodness of fit of these models was investigated. Regression coefficients (R²), root mean square error (RMSE) and correlation plots suggested that Weibull model produced a better fit to the data than the traditional model. Hazard plots suggested that the Weibull model was fully appropriate for the data being analysed. Although more studies should be carried out to evaluate the applicability of the nonlinear models, the present study has shown that thermal process calculations should most probably be reconsidered. This could lead to a reduction in under- and over-processing of thermally treated foods     

Sucrose monolaurate improves the efficacy of sodium hypochlorite against Escherichia coli O157:H7 on spinach

It is well-recognized that chlorine has limited efficacy when applied to inactivate pathogens on fresh produce. One of the many factors limiting efficacy is the high interfacial tension of chlorine-based sanitizers that limits the access of chlorine to the microorganisms. In this work, we investigated the efficacy of sodium hypochlorite (200 ppm, pH 6.0) at 4 and 20 °C against Escherichia coli O157:H7 inoculated on baby spinach leaves as affected by the surfactant sucrose monolaurate (SML) at below (100 ppm), above (250 ppm), and well above (10,000 ppm) the critical micelle concentration (CMC) of ~ 200 ppm at 20 °C. The surfactant-containing chlorine treatments were compared to those with buffer only, surfactant only, and chlorine only. Significantly improved inactivation, as evidenced by survival of E. coli O157:H7 was achieved when 250 or 10,000 ppm SML was added with chlorine. This is attributed to the reduction of interfacial tension between the sanitizing solutions and spinach surface. Treatments at 20 °C resulted in greater mean inactivation than those at 4 °C but the difference was not significant. Comparisons of SML concentrations in treatment solutions before and after sanitization showed that SML decreased more at a lower temperature and when chlorine was present, resulting from adsorption of SML onto spinach matrix. Our work illustrates the importance of using surfactants at concentrations above the CMC to enhance the efficacy of chlorine sanitization.     

The detection of Salmonella serovars from animal feed and raw chicken using a combined immunomagnetic separation and ELISA method

The immunomagnetic separation technique was used in conjunction with an ELISA-based detection system to recover Salmonella enteritidis, Salmonella typhimurium and Salmonella virchow (2–2×10³cfu 25 g⁻¹) from raw chicken and animal feed. The detection time was less than 27 h and included the conventional pre-enrichment (18 h) step in buffered peptone water and an enrichment step (6 h) in glucose nutrient broth. In contrast, the conventional method using Rappaport-Vassiliades enrichment broth and selective plating on XLD agar required 72–96 h.     

Antibacterial and antimutagenic activities of novel zerumbone analogues

Zerumbone, the key constituent of Zingiber zerumbet Smith, is a very important bioactive phytochemical. Two new compounds viz. azazerumbone 1 and azazerumbone 2 were synthesised by ZnCl₂-catalysed Beckmann rearrangement of the zerumbone oxime. The structure elucidation of these analogues of zerumbone was carried out by 1D (¹H NMR and ¹³C NMR) and 2D-NMR (COSY, HSQC and NOESY) spectral analysis. Studies on the antibacterial activity established that azazerumbone 2 had better activity than zerumbone. Among the tested bacteria, Bacillus cereus was the most sensitive and Yersinia enterocolitica was found to be the most resistant. These compounds exhibited strong protection against sodium azide induced mutagenicity of Salmonella typhimurium strains TA 98 and TA 1531. Azazerumbone 2 showed better antibacterial and antimutagenic activity than azazerumbone 1. The antibacterial and antimutagenic activities exhibited by zerumbone and its analogues demonstrate their potential for use as nutraceuticals and in food preservation.     

An innovative water-assisted UV-C disinfection system to improve the safety of strawberries frozen under cryogenic conditions

Strawberries inoculated with Salmonella enterica, Listeria monocytogenes (10⁸ CFU/mL, 50 μL) and murine norovirus (MNV-1; 10⁶ TCID₅₀/mL, 50 μL), were washed for 2 min in a water-assisted UV-C light tank (WUVC) combined or not with 40 mg/L of peracetic acid (WUVC+PA), and 200 mg/L of free chlorine solution (NaClO) with the UV-C lamps switched off. Moreover, a ‘conventional’ dry UV-C treatment (DUVC) was also tested. After 2-min exposure, washing sanitization with chemical agents gave the highest reduction for both bacteria (ca. ≥ 3.3 log CFU/g) and MNV-1 (≥1.8 log TCID₅₀/mL). DUVC treatment proved to be the least effective technology (≤0.6 log CFU/g for bacteria and 1.5 log TCID₅₀/mL for MNV-1). Regarding wash water, no presence of L. monocytogenes and S. enterica were reported with WUVC+PA and NaClO sanitization. After disinfection, samples were frozen at −70 ± 2 °C in a cryogenic freezing cabinet with liquid nitrogen (N₂). For both pathogens, frozen storage after washing substantially enhanced their inactivation in the first 3 days (1.1–4.9 log UFC/g) compared to the reductions obtained the following sampling points (0.0–0.8 log UFC/g). After 90 days, L. monocytogenes and S. enterica were not detected on the samples treated with water-assisted methodologies (WUVC, WUVC+PA and NaClO treatments), whilst MNV-1 was little affected. Further studies are needed to improve norovirus inactivation on frozen strawberries.Industrial relevanceThe present work provides relevant information to the frozen food industry regarding a suitable decontamination alternative to chlorine sanitation. Low-dose immersion-assisted UV-C allows inactivation and inhibition of pathogenic microbiota while generates non-toxic byproducts and allows reusing the process water, contributing to the so-called “smart green growth” attended to provide a more innovative and sustainable future for the food industry.     

EFFECT OF ATTACHMENT TIME FOLLOWED BY CHLORINE WASHING ON THE SURVIVAL OF INOCULATED LISTERIA MONOCYTOGENES ON TOMATOES AND SPINACH

ABSTRACT

The effect of attachment time (30 min, 24, 48 and 72 h) followed by chlorine washing (200 ppm) on the survival of inoculated Listeria monocytogenes on the surface and subsurface of tomatoes and spinach were studied. The work was done to determine the efficacy of chlorine to decontaminate surface and subsurface pathogens that may have come into contact with produce during preharvest. Tomatoes and spinach leaves were inoculated with a 6 log cfu/mL 18 h culture of L. monocytogenes ATCC 7644 (LM) on the surface and subsurface and incubated at 20C for either, 30 min, 24, 48 or 72 h. LM attached and survived on the surface and subsurface structures of both control and chlorine‐washed vegetables after each attachment time, up to 72 h. Higher levels of LM attachment and survival was however noticed on the subsurface structures. Chlorine had a greater effect on the LM on the surface structures compared to those in the subsurface structures, possibly because chlorine was not able to access the subsurface structures where the pathogens were located. Chlorine was not effective in totally inactivating the surface LM on spinach and tomato. This research indicated that LM could attach to both surface and subsurface structures of both tomatoes and spinach within 30 min and that even after 72 h, it still remained viable.

PRACTICAL APPLICATIONS

This study will inform the produce industry on the ability of L. monocytogenes ATCC 7644 to attach and grow on the surface and subsurface structures of tomato and spinach during post harvest. More attention should be given to this phenomenon because the use of fresh or minimally processed fruits and vegetables are recommended as part of a healthy diet. It also indicates that minimal processors should avoid using vegetables with wounds since L. monocytogenes attached more to the subsurfaces structures of the produce. Moreover, the use of sanitizers such as chlorine is less effective under these conditions. It has also brought to light the inability of chlorine to effectively decontaminate pathogens making it imperative for the produce industry to implement Hazard Analysis Critical Control Point, Good Agricultural Practice and Good Hygiene Practice.     

Factors influencing the microbial safety of fresh produce: A review

Increased consumption, larger scale production and more efficient distribution of fresh produce over the past two decades have contributed to an increase in the number of illness outbreaks caused by this commodity. Pathogen contamination of fresh produce may originate before or after harvest, but once contaminated produce is difficult to sanitize. The prospect that some pathogens invade the vascular system of plants and establish “sub-clinical” infection needs to be better understood to enable estimation of its influence upon risk of human illness. Conventional surface sanitation methods can reduce the microbial load, but cannot eliminate pathogens if present. Chlorine dioxide, electrolyzed water, UV light, cold atmospheric plasma, hydrogen peroxide, organic acids and acidified sodium chlorite show promise, but irradiation at 1 kGy in high oxygen atmospheres may prove to be the most effective means to assure elimination of both surface and internal contamination of produce by pathogens. Pathogens of greatest current concern are Salmonella (tomatoes, seed sprouts and spices) and Escherichia coli O157:H7 on leafy greens (spinach and lettuce). This review considers new information on illness outbreaks caused by produce, identifies factors which influence their frequency and size and examines intervention effectiveness. Research needed to increase our understanding of the factors influencing microbial safety of fresh produce is addressed.     

Evaluation of a static treatment chamber to investigate kinetics of microbial inactivation by pulsed electric fields at different temperatures at quasi-isothermal conditions

A static parallel electrode treatment chamber with tempered electrodes has been designed to obtain kinetics data on microbial inactivation by pulsed electric fields (PEF) at different temperatures at quasi-isothermal conditions. Distribution of the electric field strength and temperature within the treatment zone was estimated by a finite element method. A good agreement was observed between the temperatures estimated by numerical simulation and temperatures measured by a thermocouple in the treatment zone before and after the PEF treatments (values of RMSE below 3%). Influence of the treatment temperature on PEF inactivation (30 kV/cm) of Salmonella typhimurium was investigated at temperatures between 4 and 50 °C in media of pH 3.5 and 7.0. Treatment temperature had an important effect on microbial inactivation for both values of pH. At pH 3.5 the inactivation of S. typhimurium was irrelevant at 4 °C but about 1.5, 2.9, 4.0 and 5.0 Log₁₀ reductions were obtained after 30 pulses (90 μs) at 15, 27, 38 and 50 °C, respectively. At pH 7.0, around two Log₁₀ cycles of inactivation were observed after 50 pulses (150 μs) at 4 °C. At temperatures in the range between 15 and 50 °C the treatment temperature practically did not influence PEF resistance of S. typhimurium. A model based on the Weibull distribution adequately described kinetics of inactivation of S. typhimurium at different temperatures. The treatment chamber designed in the investigation could be useful to obtain kinetics data on PEF destruction of microorganisms or other components of interest at a uniform distribution of electric field strength and homogeneous and quasi-isothermal conditions in a wide range of temperatures.