Method development for the analysis of phthalate esters in tea beverages by ionic liquid hollow fibre liquid-phase microextraction and liquid chromatographic detection

A novel method, termed ionic liquid-based hollow fibre liquid phase microextraction (IL-HF-PLME), coupled with high-performance liquid chromatography (HPLC) was developed for separation and preconcentration of three phthalate esters (PAEs) in tea beverage. In the present study, ionic liquid 1-butyl-3-methy-limidazolium hexafluorophosphate ([BMIm]PF₆) was placed in the porous-walled polypropylene hollow fibre as the acceptor phase, and nonanol was used as the supported liquid membrane phase that accomplished extraction. Several important parameters influencing the extraction efficiency were investigated in detail. Under the optimized conditions, good linearity occurred in the range of 5–1000 ng mL⁻¹ with the correlation coefficients values above 0.998. The limits of detection ranged from 0.67 to 1.73 ng mL⁻¹. Recoveries of three PAEs in two kinds of spiked tea beverage samples (PAEs, 10.0–100.0 ng mL) were between 94.2 and 103.4%, with relative standard deviations (RSDs) ranged from 1.77 to 3.02%. The enrichment factors were 200. The developed IL-HF-PLME method allowed the simple, rapid, and sensitive determination of phthalate esters in tea beverage samples with an extraction time of just 4 min.     

Determination of melamine in milk using surface plasma effect of aggregated Au@SiO2 nanoparticles by SERS technique

A simple and rapid method to detect melamine in liquid milk by Surface-enhanced Raman Scattering (SERS) technique was presented. The pretreatment procedure of milk samples only contains hydrochloric acid treatment and twice centrifugation. In order to reduce the distortion about the Raman signals originating from charge transfer and electronic tunnelling effect, SiO₂ shell-isolated gold nanoparticles (Au@SiO₂ NPs) instead of Au NPs were employed to enhance signal intensity. Aggregation occurs when the Au@SiO₂ NPs colloid is mixed with the melamine solution or the treated milk containing melamine. Different from aggregated Au NPs, these aggregated Au@SiO₂ NPs on Cu substrate can undistortedly enhance the Raman signals of melamine using surface plasma effect. Quantitative analysis was tried and the results showed a good linearity (R² ≈ 0.99) when the melamine concentration was between 0.5 mgL⁻¹ and 5 mgL⁻¹. The detection sensitivity satisfies the requirement of the Codex Alimentarius Commission and this method can be practically used for melamine detection in milk.     

Rapid multiresidue and multi-class screening for antibiotics and benzimidazoles in feed by ultra high performance liquid chromatography coupled to tandem mass spectrometry

An analytical strategy was developed for high-throughput screening of multiple antibiotics and two benzimidazoles in feed. Generic sample processing was applied without any purification step. After methanol extraction, the samples were centrifuged, concentrated, and analysed by ultra-high-performance liquid chromatography hyphenated to tandem mass spectrometry in the multiple reaction monitoring mode. Qualitative validation was carried out for more than 50 antibacterials of various classes, including aminocoumarin, amphenicols, beta-lactams, lincosamide, macrolides, diaminopyrimidine, quinolones, sulfonamides, streptogramin, pleuromutilin, polypeptide, quinoxaline, and tetracyclines, and also some benzimidazoles in feed at μg/kg level. Validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/CE for qualitative screening methods.This convenient, reliable, and sensitive method has been used successfully to monitor antibiotic residues in feeds.     

Determination of heavy metals in selected black sea fish species

Heavy metals can be accumulated by marine organisms thought a variety of pathways, including respiration, adsorption and ingestion. The levels of heavy metals are known to increase drastically in marine environment through mainly anthropogenic activities. Fish are good indicators for the long term monitoring of metal accumulation in the marine environment. The aim of this study was to determine the levels of Cd, As, Hg, Pb, Zn and Cu in edible part and gill of seven most consumed Bulgarian fish species collected from north-east coast of Black Sea. These fish species are sprat (Sprattus sprattus sulinus), Mediterranean horse mackerel (Trachurus mediterraneus ponticus), Black sea gobies (Neogobius melanostromus), shad (Alosa pontica), Atlantic bonito (Sarda sarda), bluefish (Pomatomus saltatrix) and grey mullet (Mugil cephalus). The fish samples were collected during 2010. The analytical determination of As, Cd, Pb, Zn and Cu were performed by using flame and graphite furnace atomic absorption spectrometry after microwave digestion procedure. The total mercury determination was determined using a direct mercury analyzer (DMA-80). The metal concentration of analyzed elements was highest in the gill for all fish species. The maximum metal concentration was measured for Cu (1.40 mg kg⁻¹ w.w), Zn (11 mg kg⁻¹ w.w) and Pb (0.08 mg kg⁻¹ w.w) in muscle tissues of shad and sprat. The edible part of horse mackerel has the maximum value for Hg (0.12 mg kg⁻¹ w.w) while Atlantic bonito predominantly accumulates As (1.10 mg kg⁻¹ w.w). The analytical results obtained from this study were compared within acceptable limits for human consumption set by various health institutions.     

Determination,content analysis and removal efficiency of fining agents on ochratoxin A in Chinese wines

A simple and convenient HPLC-FD detection method for ochratoxin A (OTA) with a high detection limit and a short run time has been developed. OTA has been found in most samples of Chinese market wine, including domestic and imported wines, but the content was not very high. Only a few wines showed an OTA content that exceeded the EC and OIV limits, indicating that most Chinese market wines were safe. The OTA intake for Chinese from wine was 0.017 ng/kg (bw) per day, which was lower than the SCF and JECFA limits and also lower than in many other countries. This was mainly due to the low per capita wine consumption in China, but it is still necessary for the Chinese government and wine makers to monitor OTA levels in wine and to establish relevant regulations. An egg white treatment (0.20 mg/mL, 48 h) was the best removal method for OTA.     

Vegetable oil as fat replacer inhibits formation of heterocyclic amines and polycyclic aromatic hydrocarbons in reduced fat pork patties

Formation of heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) was examined to evaluate the impact of using vegetable oil as fat replacement on carcinogen formation in meat product. Pork patties were formulated with 40% fat replacement by olive oil, sunflower oil or grape seed oil, respectively and cooked at 180 °C or 220 °C. Control patties contained the highest amount of HCAs compared with all other patties at both temperatures. Olive oil and sunflower oil replacement completely inhibited formation of MeIQ (2-amino-3, 4-dimethylimidazo[4,5-f]quinoline), while grape seed oil completely inhibited MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) in patties. Grape seed oil achieved the highest inhibition capacity compared with sunflower oil and olive oil. HCAs increased significantly with cooking temperature (p < 0.05), but no difference was observed in total PAHs for patties cooked at different temperature (p > 0.05). In conclusion, fat replacement with sunflower oil, olive oil or grape seed oil in pork patties could reduce the formation of HCAs without compromising eating quality.     

Heterocyclic amines and polycyclic aromatic hydrocarbons in commercial ready-to-eat meat products on UK market

Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), which are developed during meat processing, may play key roles in the imposing health risk. The consumption of ready to eat (RTE) meat products has increased dramatically in recent years due to their convenience. Therefore, it is essential to evaluate its health risk and provide dietary intake guidance to the general public. 11 RTE meat products were selected from UK market including chicken, pork and fish to investigate their health risks in concern of HCAs and PAHs levels. HCAs and PAHs were extracted by solid-phase extraction and analysed by HPLC-DAD/FLU. Chargrilled chicken contained the highest amount of HCAs (37.45 ± 4.89 ng/g) and PAHs (3.11 ± 0.49 ng/g), followed by roasted bacon (HCAs 15.24 ± 1.31 ng/g, PAHs 1.75 ± 0.17 ng/g) and honey roast salmon (HCAs 17.12 ± 5.86 ng/g, PAHs 0.38 ± 0.09 ng/g). The high dietary intake of HCAs was from chargrilled chicken and ham, which could contribute to the increase in breast cancer and colorectal adenoma. While cancer risk associated with PAHs intake from RTE meat products was relatively low according to the Lifelong Average Daily Intake of UK consumers.     

Inhibition of Fusarium culmorum by carboxylic acids released from lactic acid bacteria in a barley malt substrate

The effect of carboxylic acids, composed by both organic and phenolic acids, released in a barley malt substrate fermented by lactic acid bacteria was tested against Fusarium culmorum macroconidia and compared under different fermentation conditions. Phenolic acids released by Lactobacillus plantarum FST1.7 and Lactobacillus brevis R2Δ were quantified using a QuEChERS method coupled with a HPLC-UV/PDA system. Their concentration improved with increasing extract content of the barley malt-based substrate and reached maximal concentrations after 48 h of fermentation performed at optimum growth temperature. Generally, phenolic acids were produced at levels far below their minimal inhibitory concentration (MIC), and limited synergistic effects were observed when mixed with organic acids. The fungal growth suppression by the wort fermented by Lb. brevis R2Δ (95 ± 9 h total inhibition) could be fully explained by the presence of antifungal carboxylic acids, whereas only partially accounted for Lb. plantarum FST1.7 (198 ± 19 h). Organic acids were mainly responsible for the ability of LAB fermented wort to cause fungal inhibition, whereas phenolic acids took only a secondary role at the low concentrations released. Longer fermentation times favoured primarily organic acid release, whereas fermentation of higher malt extract substrates encouraged both organic and phenolic acids production. The understanding on how synergy works between antifungal compounds could help to identify strategies to further increase their concentration in wort, with potential to replace synthetic broths and for direct application in food application.     

Identification of antifungal peptides produced by Lactobacillus plantarum IS10 grown in the MRS broth

The use of secondary metabolites of lactic acid bacteria for preservation of foods is increasingly gaining interest to the food industry to replace synthetic preservatives. In this study, the cell free supernatant containing peptides obtained from Lactobacillus plantarum IS10 was fractionated by size exclusion chromatography using sephadex G-25, and tested against Aspergillus flavus MD3, Penicillium roqueforti MD4 and Eurotium rubrum MD5. Among the fractions, fraction number 10 showed 60% antifungal activity at a concentration of 0.02 mg peptide/mL. Four novel peptides out of twenty peptides obtained from fraction 10 were identified and determined by de novo sequencing. Peptide FPSHTGMSVPPP with a net charge +1, hydrophobicity ratio 58% and molecular weight of 1253 was further studied. The selected peptide showed a good activity at a concentration of 5 mg/mL against selected fungi and poor activity at low concentrations. This work indicates that L. plantarum IS10 has the capability of producing peptides which are affective against spoilage fungi.     

Antibiotic and synthetic growth promoters in animal diets: Review of impact and analytical methods

Food quality and safety have been a significant and pressing issue in recent years. In light of the FAO's definition of food security – the physical, social and economic access to sufficient and nutritious food – food safety plays a fundamental role. Animal feed and feeding is pivotal to the livestock industry, but the use of veterinary antibiotics (VAs) and synthetic growth promoters (SGP) diminishes the sustainability of the diets and can cause an accumulation of residues in animals (meat, milk and eggs) and the environment (water and soil pollution). Wastewater systems are another major pathway through which antibiotics and hormones can enter the environment, with negative consequences. In order to protect the planet through more sustainable feeding, the reduction of antibiotics and synthetic growth promoters is a key aim, in particular with the goal of reducing antibiotic resistance and allergies. Analytical methods play a crucial role in food analysis, to determine the presence of antibiotics and other additives. Recent methods are based on liquid chromatography with ultraviolet, fluorescence, or mass spectrophotometry detection, which is recognized as an essential technique in food analysis, able to identify more than 300 compounds in feed samples. In general, a monitoring program put in place to educate the population on the hazards of residues in animal products is necessary, in conjunction with a continuous decrease in the use of antibiotics and synthetic growth promoters in animal diets.     

Simultaneous determination of mycotoxin in commercial coffee

Mycotoxins are secondary metabolites produced by filamentous fungi that usually contaminate food products. Coffee is a natural product susceptible to mycotoxin contamination. The present study evaluates the presence of nivalenol, deoxynivalenol, T-2 and HT-2 Toxin, diacetoxyscirpenol, aflatoxin B₁, aflatoxin B₂, aflatoxin G₁, aflatoxin G₂, fumonisin B₁, fumonisin B₂, ochratoxin A, zearalenone, enniatin A, enniatin A₁, enniatin B, enniatin B₁, and beauvericin in coffee samples, using liquid chromatography tandem mass spectrometry (LC-MS/MS). The results show that zearalenone was not present in any sample. In the positive samples the contents of fumonisins ranged from 58.62 to 537.45 μg/kg, emerging mycotoxins ranged from 0.10 to 3569.92 μg/kg, aflatoxins ranged from 0.25 to 13.12 μg/kg, and trichothecenes, excepting nivalenol, ranged from 5.70 to 325.68 μg/kg. Nivalenol presented the highest concentrations, from 0.40 to 25.86 mg/kg. Ochratoxin A ranged from 1.56 to 32.40 μg/kg, and five samples exceeded the maximum limit established by the European Commission.     

Concentration and survey of phthalic acid esters in edible vegetable oils and oilseeds by gas chromatography-mass spectrometry in China

Now, there is a lack of information regarding the occurrence and the content of phthalic acid esters (PAEs) contamination in edible vegetable oils and oilseeds used for oil production in China. In this study, a method for determination of five PAEs was developed based on gas chromatography-mass spectrometry. Method recoveries for oils and oilseeds were 72.4–103.0% and 77.2–98.8%, respectively. RSDs of five analytes in oils and oilseeds were ranging from 1.22 to 8.64% and 0.62–9.37%, respectively. The LODs and LOQs were ranging from 0.10 to 0.79 and 0.33–2.60 μg/kg, respectively. Based on the established method, PAE concentrations in thirty-four edible oils and twenty-eight oilseeds were evaluated. Five and thirteen oil samples exceeded the upper limits 1.5 and 0.3 mg/kg set for di(2-ethtlhexyl) phthalate and dibutyl phthalate in China, respectively. The results obtained indicated that more concern and comprehensive legislation are still needed and mulriple issues should be considered when it comes to the PAEs contamination in edible vegetable oils.     

Occurrence and co-occurrence of Fusarium mycotoxins in wheat grains and wheat flour from Romania

In this study, the presence of fourteen Fusarium mycotoxins, legislated by the European Union – deoxynivalenol, zearalenone, HT-2 and T-2 toxins (EC/1881/2006; 2013/165/EU), or non-legislated (five trichothecens and five “emerging” mycotoxins), was evaluated in 31 whole unprocessed wheat samples and 35 white wheat flour samples from different areas of Romania. For this purpose, a validated multi-mycotoxins liquid chromatography tandem mass spectrometry method was applied. Seventy three percent of the analyzed samples contained at least one mycotoxin. The highest occurrence was for enniatin B, 71% of the analyzed samples being positive (21–407 μg kg⁻¹). Regarding the legislated mycotoxins, deoxynivalenol was detected in 14% (111–1787 μg kg⁻¹) of the samples, while zearalenone was detected in 9% (51–1135 μg kg⁻¹). Only one sample was positive for neosolaniol. Concerning the co-occurrence, 42% of the samples were contaminated with two to five mycotoxins, the most frequent being the binary or tertiary combinations of enniatins. This is the first study applied to Romanian wheat grains and flour samples using a high sensitive multi-mycotoxins method, and which included also “emerging” mycotoxins.     

Minerals in vitro bioaccessibility and changes in textural and structural characteristics of uncooked pre-germinated brown rice influenced by ultra-high pressure

Ultra-high pressure (UHP) is considered as an effective processing method to enhance micronutrients utilization efficiency in germinated brown rice (GBR), but there is little information available for the effects of UHP treatments on mineral bioaccessibility and related structural characteristics. Therefore, this work examined the changes induced by UHP in the in vitro bioaccessibility of selected minerals and structural and textural properties at pressures, as well as their potential relationship. UHP treatments were applied at 100, 300 and 500 MPa for 10 min, and 0.1 MPa as control. Proximate analysis showed that free fatty acids (FFA) and moisture in GBR greatly increased after UHP treatment. Three representative minerals with different levels were chosen to assess the bioaccessibility, including phosphorus (P), magnesium (Mg) and manganese (Mn). The results demonstrated that the minerals bioaccessibility, measured by percentage solubility, were the highest when at 300 MPa whereas it decreased at 500 MPa. Correspondingly, microstructure imaging by scanning electron microscope (SEM) showed that the gelatinization of starch granule occurred at 300 MPa and it became more obvious when increased to 500 MPa. Starch gelatinization significantly lowered the hardness of GBR grains, simultaneously accompanied with the decrease of cohesiveness, gumminess and resilience through texture profile analysis (TPA). Multivariate analysis by principal component analysis and canonical correspondence analysis indicated a highly intra-associated (p < 0.01) TPA parameters and a close correlation between the bioaccessibility and hardness, chewiness and springiness. These results provide information on minerals bioaccessibility and structural properties of uncooked GBR after UHP treatment, which could lay the foundation for further elucidating the correlation between structure and micronutrients bioaccessibility.     

Multiple mycotoxin co-occurrence in maize grown in three agro-ecological zones of Tanzania

In this study, the co-occurrence of multiple mycotoxins in maize kernels collected from 300 households' stores in three agro-ecological zones in Tanzania was evaluated by using ultra high performance liquid chromatography/time-of-flight mass spectrometry (TOFMS) with a QuEChERS-based procedure as sample treatment. This method was validated for the analysis of the main eleven mycotoxins of health concern that can occur in maize: aflatoxin B₁ (AFB₁), aflatoxin B₂ (AFB₂), aflatoxin G₁ (AFG₁), aflatoxin G₂ (AFG₂), ochratoxin A (OTA), deoxynivalenol (DON), fumonisin B₁ (FB₁), fumonisin B₂ (FB₂), HT-2 toxin, T-2 toxin and zearalenone (ZEN). From each zone one major maize producing district for home consumption was chosen and 20 villages for each district were randomly selected for sampling. All mycotoxins of health concern, except for T-2 toxin, were detected in the maize samples. Particularly high levels of AFB₁ (50%; 3–1,081 μg kg⁻¹), FB₁ (73%; 16–18,184 μg kg⁻¹), FB₂ (48%; 178–38,217 μg kg⁻¹) and DON (63%; 68–2,196 μg kg⁻¹) were observed. Some samples exceeded the maximum limits set in Tanzania for aflatoxins or in European regulations for other mycotoxins in unprocessed maize. Eighty seven percent of samples were contaminated with more than one mycotoxin, with 45% of samples co-contaminated by carcinogenic mycotoxins, aflatoxins and fumonisins. Significant differences in contamination pattern were observed among the three agro-ecological zones. The high incidence and at high levels (for some) of these mycotoxins in maize may have serious implications on the health of the consumers since maize constitute the staple food of most Tanzanian population. Effective strategies targeting more than one mycotoxin are encouraged to reduce contamination of maize with mycotoxins.     

Latex bead and colloidal gold applied in a multiplex immunochromatographic assay for high-throughput detection of three classes of antibiotic residues in milk

Two rapid and sensitive high-throughput immunochromatographic assays were successfully developed for simultaneous determination of 12 sulfonamide, 18 quinolone and six tetracycline residues in milk. Under optimized conditions, residues from these three classes of antibiotics can be qualitatively and quantitatively determined on a single strip within 10 min. The detection limits were much lower than the maximum residue limits established by the European Union. Comparative evaluations of sensitivity, antibody consumption, coefficient of variation and user experience between these two immunochromatographic assays showed that latex beads have advantages over colloidal gold when employed as a label in the assay. Therefore, the latex bead-based high-throughput immunochromatographic assay has the best potential for on-site testing of a large number of samples as part of food safety applications.     

Three years of monitoring of PCDD/F,DL-PCB and NDL-PCB residues in bovine milk from Lombardy and Emilia Romagna regions (Italy): Contamination levels and human exposure assessment

In the three-years period 2012–2014, 160 cow milk samples from farms located in Lombardy and Emilia Romagna regions (Italy) were analyzed during the implementation of the Italian National Residues Monitoring Plan to assess the presence of PCDD/F, DL-PCB and NDL-PCB residues. The obtained contamination data were combined with cow milk consumption data from the Italian national dietary survey to estimate PCDD/F, DL-PCB and NDL-PCB human dietary exposure through the consumption of whole, semi skimmed and skimmed bovine milk. The exposure assessment was carried out separately for children, teenagers, adults and elderly. Average contamination levels of the analyzed samples were found to be 1.26 pg WHO-TEQ/g fat for the sum of PCDD/Fs and DL-PCBs and 9.30 ng/g fat for the sum of the 6 NDL-PCB indicators. PCB 126 was found to be the main contributor to the total WHO-TEQ. Using the upper bound approach, the estimated mean dietary intakes ranged from 0.07 pg WHO-TEQ/kg bw per day to 0.39 pg WHO-TEQ/kg bw per day for the sum of PCDD/Fs and DL-PCBs and considering exposure from whole milk. NDL-PCB mean dietary intakes resulted between 0.52 ng/kg bw per day and 2.86 ng/kg bw per day for consumption of whole milk. Children and teenagers were found to be the most exposed groups. This is the first time that Italian consumers exposure to NDL-PCBs is assessed using contamination data of cow milk produced in Italy.     

Determination and occurrence of 5-hydroxymethyl-2-furaldehyde in white and brown sugar by high performance liquid chromatography

5-hydroxymethyl-2-furaldehyde (HMF) is not only indicator of food freshness and quality, but also contaminant forming during Maillard reaction, or by dehydratation of saccharides, respectively. While data about presence of HMF in white and brown sugar are scarce, 13 kinds of white sugar and 25 kinds of brown sugar were analysed. Sugar was dissolved in deionised water, clarified with Carrez solutions, filtered and content of HMF was determined using high performance liquid chromatography with diode array detector (HPLC-DAD) with detection at 284 nm when separation run on Poroshel 120 EC C18 at 32 °C. Elution was performed under isocratic conditions using 95:5 water/acetonitrile mobile phase at a flow rate of 0.9 mL/min and analysis run 5 min. Method was validated in in house regime and its parameters such as limit of detection – (LOD = 0.05 mg/kg), limit of quantification (LOQ = 0.15 mg/kg), specificity, repeatability and recovery enabled its application for sugar analysis. While white sugar was free of HMF, all kinds of brown sugar exhibited presence of HMF, when content in 15 kinds varied between 0.17 and 6.45 mg/kg, content in other 10 kinds was under LOQ. On the base of obtained results was postulated that brown sugar contains HMF either due to absence of refining processes, or it is re-contaminated by treacle adding to white sugar during production of brown sugar.     

Effect of sulfur dioxide and ethanol concentration on fungal profile and ochratoxin a production by Aspergillus carbonarius during wine making

Fungal profiles and ochratoxin A (OTA) accumulation during wine making were investigated using five different wine grape cultivars, Cabernet Sauvignon, Pinot Noir, Merlot, Syrah and Petit Verdot and the intrinsic influences caused by sulfur dioxide, ethanol and combine effect of ethanol and reducing sugar were analyzed using Cabernet Sauvignon and inoculation of Aspergillus carbonarius. Aspergillus spp. and Penicillium spp. were found as the major fungi in all winemaking processes and were highly correlated with OTA accumulation in wine. Most fungi died and OTA production decreased after 48 h of alcoholic fermentation, being consistent with the period when ethanol accumulation increased. The addition of SO₂ significantly inhibited the growth and OTA production of A. carbonarius with complete inhibition at 500 mg/L. When the ethanol concentration in the must increased to the range of 2–4%, growth and OTA production of A. carbonarius were significantly inhibited. Reducing sugar concentration had no significant effect on the growth and OTA production of A. carbonarius within the levels changing during the winemaking. Therefore, the increase of ethanol concentration played an important role in causing the decrease of fungal contamination and OTA accumulation during winemaking.     

Combination treatment of ohmic heating with various essential oil components for inactivation of food-borne pathogens in buffered peptone water and salsa

Consumer preference for minimally processed foods has steadily increased for several years, while foodborne outbreaks from under-processed foods continue to be reported worldwide. We investigated the combination effect of ohmic heating with various essential oil components for inactivation of foodborne pathogens in buffered peptone water and salsa. We choose carvone, eugenol, thymol, and citral to combine with ohmic heating, which are registered for use as flavorings in foodstuffs. Combination treatment of ohmic heating with citral showed the most synergistic bactericidal effect against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in buffered peptone water followed by thymol, eugenol, and carvone. When enumerated on selective media, the reductions were 4.8, 5.7, and 4.3 log CFU/ml for E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. Cell membrane destruction by combination treatment and the loss of cell membrane potential by essential oil components were proposed as the bactericidal mechanism. When applied in salsa, inactivation of bacterial pathogens was the greatest with the ohmic and thymol combination treatment followed by citral, eugenol, and carvone. A synergistic virucidal effect was observed for MS -2 bacteriophage, which was used as a norovirus surrogate. Color (b* values) of salsa were improved by combination treatment of ohmic heating and thymol compared to ohmic treated samples. Therefore, the combination treatment of ohmic heating and thymol could be used effectively to pasteurize salsa.