Antimicrobial activity of pomegranate peel extracts as affected by cultivar.

BACKGROUND: Some studies have reported that different parts of the pomegranate fruit, especially the peel, may act as potential antimicrobial agents and thus might be proposed as a safe natural alternative to synthetic antimicrobial agents. The high tannin content, especially punicalagin, found in pomegranate extracts, has been reported as the main compound responsible for such antimicrobial activity. Because the pomegranate peel chemical composition may vary with the type of cultivar (sweet, sour-sweet and sour), pomegranates may also differ with respect to their antimicrobial capacity. RESULTS: The extract from PTO8 pomegranate cultivar peel had the highest antimicrobial activity, as well as the highest punicalagins (α and ß) and ellagic acid concentrations. In the results obtained from both antibacterial and antifungal activity studies, the sour-sweet pomegranate cultivar PTO8 showed the best antimicrobial activity, and the highest ellagic acid concentrations. CONCLUSION: The results of the present study suggest that ellagic acid content has a significant influence on the antimicrobial activity of the pomegranate extracts investigated. The pomegranate peel of the PTO8 cultivar is a good source of antifungal and antibacterial compounds, and may represent an alternative to antimicrobial agents of synthetic origin. © 2016 Society of Chemical Industry.

Antimicrobial activity of coriander oil and its effectiveness as food preservative.

ABTRACT Foodborne illness represents a major economic burden worldwide and a serious public health threat, with around 48 million people affected and 3,000 death each year only in the USA. One of the possible strategies to reduce foodborne infections is the development of effective preservation strategies capable of eradicating microbial contamination of foods. Over the last years, new challenges for the food industry have arisen such as the increase of antimicrobial resistance of foodborne pathogens to common preservatives and consumers demand for naturally based products. In order to overcome this, new approaches using natural or bio-based products as food preservatives need to be investigated. Coriander (Coriandrum sativum L.) is a well-known herb widely used as spice, or in folk medicine, and in the pharmacy and food industries. Coriander seed oil is the world's second most relevant essential oil, exhibiting antimicrobial activity against Gram-positive and Gram-negative bacteria, some yeasts, dermatophytes and filamentous fungi. This review highlights coriander oil antimicrobial activity and possible mechanisms of action in microbial cells and discusses the ability of coriander oil usage as a food preservative, pointing out possible paths for the successful evolution for these strategies towards a successful development of a food preservation strategy using coriander oil.

Effect of edible coatings with essential oils on the quality of red raspberries over shelf-life.

BACKGROUND: The objective of the present work was to develop strategies for increasing the shelf-life of red raspberries (Rubus idaeus L.), by preventing microorganism growth. RESULTS: Fruits coated with alginate plus lemon essential oil (0.2%) or orange essential oil (0.1%) after 15 days of storage had less red skin than the remaining samples. The less red color verified in these samples was also coincident with the lower concentration of anthocyanins at the end of the experiment as well as the lower capacity for scavenging ABTS free radicals or quenching singlet oxygen. Cyanidin and pelargonidin glucosides were found in raspberries fruits. The edible coatings supplemented with the essential oil of orange either at 0.1% or 0.2% were very efficient for controlling yeast and mold growth after 15 days of storage. To control the development of aerobic mesophilic bacteria the use of essential oil of lemon 0.2% and essential oil of orange 0.1% were the most efficient. CONCLUSION: The application of the film improved post-harvest quality of raspberry, since the addition of essential oils of citrus films promoted to the inhibitory effect of fungi and bacteria growth after 15 days of storage, without changing quality parameters. © 2016 Society of Chemical Industry.

Heracleum orphanidis: chemical characterisation, and comparative evaluation of antioxidant and antimicrobial activities with specific interest in the influence on Pseudomonas aeruginosa PAO1.

GC-FID and GC-MS were used to determine the chemical composition of the essential oil of the aerial parts of Heracleum orphanidis Boiss. Also, the HPLC-DAD/ESI-ToF-MS profile of the methanol extracts of aerial parts and roots was determined. The main components of the essential oil were n-octanol, octyl hexanoate and n-octyl acetate, while coumarins were the most prevalent compounds in methanol extracts. An evaluation of antioxidant activity showed that the methanol and aqueous extracts of the aerial parts had the highest potential. In terms of antimicrobial activity determined by microdilution assays, the essential oil and methanol extract of the roots showed the greatest effectiveness. The colonies of Pseudomonas aeruginosa PAO1 treated with H. orphanidis samples produced less toxic pyocyanin, showed lower twitching and flagella mobility and biofilm formatting was reduced. The analyses in this study showed the considerable biological potential of H. orphanidis considering free radicals and various pathogenic strains, including the wild type of P. aeruginosa.

Antimicrobial Activity of Ferulic Acid Against Cronobacter sakazakii and Possible Mechanism of Action.

Cronobacter sakazakii is an opportunistic pathogen transmitted by food that affects mainly newborns, infants, and immune-compromised adults. In this study, the antibacterial activity of ferulic acid was tested against C. sakazakii strains. Minimum inhibitory concentration of ferulic acid against C. sakazakii strains was determined using the agar dilution method. Changes in intracellular pH, membrane potential and intracellular ATP concentration were measured to elucidate the possible antibacterial mechanism. Moreover, SYTO 9 nucleic acid staining was used to assess the effect of ferulic acid on bacterial membrane integrity. Cell morphology changes were observed under a field emission scanning electron microscope. The minimum inhibitory concentrations of ferulic acid against C. sakazakii strains ranged from 2.5 to 5.0 mg/mL. Addition of ferulic acid exerted an immediate and sustained inhibition of C. sakazakii proliferation. Ferulic acid affected the membrane integrity of C. sakazakii, as evidenced by intracellular ATP concentration decrease. Moreover, reduction of intracellular pH and cell membrane hyperpolarization were detected in C. sakazakii after exposure to ferulic acid. Reduction of green fluorescence indicated the injury of cell membrane. Electronic microscopy confirmed that cell membrane of C. sakazakii was damaged by ferulic acid. Our results demonstrate that ferulic acid has moderate antimicrobial activity against C. sakazakii. It exerts its antimicrobial action partly through causing cell membrane dysfunction and changes in cellular morphology. Considering its antimicrobial properties, together with its well-known nutritional functions, ferulic acid has potential to be developed as a supplement in infant formula or other foods to control C. sakazakii.

p-Coumaric acid and its conjugates: dietary sources, pharmacokinetic properties and biological activities.

p-Coumaric acid (4-hydroxycinnamic acid) is a phenolic acid that has low toxicity in mice (LD50 = 2850 mg kg(-1) body weight), serves as a precursor of other phenolic compounds, and exists either in free or conjugated form in plants. Conjugates of p-coumaric acid have been extensively studied in recent years due to their bioactivities. In this review, the occurrence, bioavailability and bioaccessibility of p-coumaric acid and its conjugates with mono-, oligo- and polysaccharides, alkyl alcohols, organic acids, amine and lignin are discussed. Their biological activities, including antioxidant, anti-cancer, antimicrobial, antivirus, anti-inflammatory, antiplatelet aggregation, anxiolytic, antipyretic, analgesic, and anti-arthritis activities, and their mitigatory effects against diabetes, obesity, hyperlipaemia and gout are compared. Cumulative evidence from multiple studies indicates that conjugation of p-coumaric acid greatly strengthens its biological activities; however, the high biological activity but low absorption of its conjugates remains a puzzle. © 2015 Society of Chemical Industry.

Influence of the antimicrobial compound allyl isothiocyanate against the Aspergillus parasiticus growth and its aflatoxins production in pizza crust.

Aflatoxins (AFs) are secondary metabolites produced by different species of Aspergillus, such as Aspergillus flavus and Aspergillus parasiticus, which possess mutagenic, teratogenic and carcinogenic activities in humans. In this study, active packaging devices containing allyl isothiocyanate (AITC) or oriental mustard flour (OMF) + water were tested to inhibit the growth of A. parasiticus and AFs production in fresh pizza crust after 30 d. The antimicrobial and anti-aflatoxin activities were compared to a control group (no antimicrobial treatment) and to a group added with commercial preservatives (sorbic acid + sodium propionate). A. parasiticus growth was only inhibited after 30 d by AITC in filter paper at 5 µL/L and 10 µL/L, AITC sachet at 5 µL/L and 10 µL/L and OMF sachet at 850 mg + 850 µL of water. However, AFs production was inhibited by all antimicrobial treatments in a dose-dependent manner. More importantly, AITC in a filter paper at 10 µL/L, AITC sachet at 10 µL/L, OMF sachet at 850 mg + 850 µL of water and sorbic acid + sodium propionate at 0.5-2.0 g/Kg completely inhibited AFs formation. The use of AITC in active packaging devices could be a natural alternative to avoid the growth of mycotoxinogenic fungi in refrigerated bakery products in substitution of common commercial preservatives.

The Maillard reaction of a shrimp by-product protein hydrolysate: chemical changes and inhibiting effects of reactive oxygen species in human HepG2 cells.

Recently, much attention has been given to improving the antioxidant activity of protein hydrolysates via the Maillard reaction, but little is known about the cellular antioxidant activity of Maillard reaction products (MRPs) from protein hydrolysates. We first investigated chemical characterization and the cellular antioxidant activity of MRPs in a shrimp (Litopenaeus vannamei) by-product protein hydrolysate (SBH)-glucose system at 110 °C for up to 10 h of heating. Solutions of SBH and glucose were also heated alone as controls. The Maillard reaction greatly resulted in the increase of hydroxymethylfurfural (HMF) and browning intensity, high molecular weight fraction, and reduction of the total amino acid in SBH with the heating time, which correlated well with the free radical scavenging activity of MRPs. MRPs had stronger inhibiting effects on oxidative stress of human HepG2 cells than the original SBH, and its cellular antioxidant activity strongly correlated with free radical scavenging activity, but less affected by the browning intensity and HMF level. The caramelization of glucose partially affected the HMF level and free radical scavenging activity of MRPs, but it was not related to the cellular antioxidant activity. The cellular antioxidant activity of MRPs for 5 h of heating time appeared to reach a maximum level, which was mainly due to carbonyl ammonia condensation reaction. In conclusion, the Maillard reaction is a potential method to increase the cellular antioxidant activity of a shrimp by-product protein hydrolysate, but the higher HMF levels and the lower amino acid content in MRPs should also be considered.

Effect of Essential Oils on Germination and Growth of Some Pathogenic and Spoilage Spore-Forming Bacteria.

The use of essential oils as a food preservative has increased due to their capacity to inhibit vegetative growth of some bacteria. However, only limited data are available on their effect on bacterial spores. The aim of the present study was to evaluate the effect of some essential oils on the growth and germination of three Bacillus species and Geobacillus stearothermophilus. Essential oils were chemically analyzed using gas chromatography and gas chromatography coupled to mass spectrometry. The minimal inhibitory and bactericidal concentrations of vegetative growth and spore germination were assessed using the macrodilution method. Germination inhibitory effect of treated spores with essential oils was evaluated on solid medium, while kinetic growth was followed using spectrophotometry in the presence of essential oils. Essential oil from Drypetes gossweileri mainly composed of benzyl isothiocyanate (86.7%) was the most potent, with minimal inhibitory concentrations ranging from 0.0048 to 0.0097 mg/mL on vegetative cells and 0.001 to 0.002 mg/mL on spore germination. Furthermore, essential oil from D. gossweileri reduced 50% of spore germination after treatment at 1.25 mg/mL, and its combination with other oils improved both bacteriostatic and bactericidal activities with additive or synergistic effects. Concerning the other essential oils, the minimal inhibitory concentration ranged from 5 to 0.63 mg/mL on vegetative growth and from 0.75 to 0.09 mg/mL on the germination of spores. Spectrophotometric evaluation showed an inhibitory effect of essential oils on both germination and outgrowth. From these results, it is concluded that some of the essential oils tested might be a valuable tool for bacteriological control in food industries. Therefore, further research regarding their use as food preservatives should be carried out.

Efficiency of Artemisia nilagirica (Clarke) Pamp. essential oil as a mycotoxicant against postharvest mycobiota of table grapes.

BACKGROUND: In order to get a potent botanical fungicide for the management of fungal decay of table grapes, an experiment was conducted in which 20 essential oils of higher plants were screened at 0.33 µL mL(-1) against dominant fungi causing decay of table grapes, including Aspergillus flavus, A. niger and A. ochraceus. Furthermore, the minimum inhibitory/fungicidal concentration, fungitoxic spectrum and mycotoxin inhibition activity of the most potent oil were determined. The efficacy of the most potent oil in preservation of table grapes, along with organoleptic evaluation, was also carried out by storing 1 kg of grapes in the oil vapour. RESULTS: Artemisia nilagirica oil was found to be most toxic, exhibiting 100% mycelia inhibition of all test fungi. Moreover, 0.29 µL mL(-1) A. nilagirica oil was fungistatic and 0.58 µL mL(-1) was fungicidal for all tested species of Aspergillus. The oil exhibited a broad range of fungitoxicity against other grape berry-rotting fungi. Artemisia nilagirica oil completely suppressed the growth and mycotoxin (AFB1 and OTA) secretion of aflatoxigenic and ochratoxigenic strains of Aspergillus at 1.6 µL mL(-1) . During the in vivo experiment, fumigation of 1 kg of table grapes with 200 and 300 µL dosage of A. nilagirica oil enhanced the shelf life for up to 9 days. The oil did not show any phytotoxic effect. Besides, oil application did not substantively change the sensory properties of the fruits. CONCLUSION: Artemisia nilagirica oil can be used as an alternative botanical fungicide for the control of fruit-rotting fungi of stored grapes.

Synergy of licorice extract and pea protein hydrolysate for oxidative stability of soybean oil-in-water emulsions.

Previously developed radical-scavenging pea protein hydrolysates (PPHs) prepared with Flavourzyme (Fla-PPH) and Protamex (Pro-PPH) were used as cosurfactants with Tween 20 to produce soybean oil-in-water (O/W) emulsions, and the suppression of lipid oxidation was investigated. Both PPHs significantly retarded oxidation (P < 0.05) of the emulsions when stored at 37 °C for 14 days. Electron microscopy revealed an interfacial peptidyl membrane around oil droplets, which afforded steric restrictions to oxidation initiators. When licorice extract (LE) was also used in emulsion preparation, a remarkable synergistic oxidation inhibition was observed with both PPHs. LE adsorbed onto oil droplets either directly or through associating with PPH to produce a thick and compact interfacial membrane enabling the defense against oxygen species. Liquiritin apioside, neolicuroside, glabrene, and 18ß-glycyrrhetic acid were the predominant phenolic derivatives partitioning at the interface and most likely the major contributors to the notable synergistic antioxidant activity when coupled with PPHs.

Industrial production of L-ascorbic Acid (vitamin C) and D-isoascorbic acid.

L-ascorbic acid (vitamin C) was first isolated in 1928 and subsequently identified as the long-sought antiscorbutic factor. Industrially produced L-ascorbic acid is widely used in the feed, food, and pharmaceutical sector as nutritional supplement and preservative, making use of its antioxidative properties. Until recently, the Reichstein-Grüssner process, designed in 1933, was the main industrial route. Here, D-sorbitol is converted to L-ascorbic acid via 2-keto-L-gulonic acid (2KGA) as key intermediate, using a bio-oxidation with Gluconobacter oxydans and several chemical steps. Today, industrial production processes use additional bio-oxidation steps with Ketogulonicigenium vulgare as biocatalyst to convert D-sorbitol to the intermediate 2KGA without chemical steps. The enzymes involved are characterized by a broad substrate range, but remarkable regiospecificity. This puzzling specificity pattern can be understood from the preferences of these enyzmes for certain of the many isomeric structures which the carbohydrate substrates adopt in aqueous solution. Recently, novel enzymes were identified that generate L-ascorbic acid directly via oxidation of L-sorbosone, an intermediate of the bio-oxidation of D-sorbitol to 2KGA. This opens the possibility for a direct route from D-sorbitol to L-ascorbic acid, obviating the need for chemical rearrangement of 2KGA. Similar concepts for industrial processes apply for the production of D-isoascorbic acid, the C5 epimer of L-ascorbic acid. D-isoascorbic acid has the same conformation at C5 as D-glucose and can be derived more directly than L-ascorbic acid from this common carbohydrate feed stock.

Extraction and quantitation of coumarin from cinnamon and its effect on enzymatic browning in fresh apple juice: a bioinformatics approach to illuminate its antibrowning activity.

Enzymatic browning by polyphenoloxidase (PPO) affects food quality and taste in fruits and vegetables. Thus, the study was designed to reduce browning in apple juice by coumarin. The ethanolic extract of cinnamon was prepared and its coumarin content was quantitated by HPLC, using authentic coumarin (AC) as standard. The effect of cinnamon extract (CE) and AC on enzymatic browning, its time dependent effects, and the specific activity of PPO and peroxidase (POD) were studied in apple juice. The docking of coumarin with PPO and POD was also performed to elucidate its antibrowning mechanism. The CE (73%) and AC (82%) showed better reduction in browning, maintained its antibrowning effect at all time points, and significantly (p < 0.05) reduced the specific activity of PPO and POD when compared with controls. Coumarin showed strong interaction with binding pockets of PPO and POD, suggesting its potential use as inhibitor to enzyme mediated browning in apple juice.

Characterization of nitrated phenolic compounds for their anti-oxidant, pro-oxidant, and nitration activities.

Coffee is one of the most widely consumed beverages worldwide. Evidence of the health benefits and the important contribution of coffee brew to the intake of anti-oxidants in the diet has increased coffee consumption. Chlorogenic acid (ChA) and caffeic acid (CaA) are the major phenolic compounds in coffee. However, phenolic compounds, which are generally effective anti-oxidants, can become pro-oxidants in the presence of Cu(2+) to induce DNA damage under certain conditions. On the other hand, sodium nitrite (NaNO(2)) is widely used as a food additive to preserve and tinge color on cured meat and fish. It is possible that phenolic compounds react with NaNO(2) under acidic conditions, such as gastric juice. In this study, we identified compounds produced by the reaction between ChA or CaA in coffee and NaNO(2) in artificial gastric juice. The identified phenolic compounds and nitrated phenolic compounds were assessed for their anti-oxidant, pro-oxidant, and nitration activities by performing an in vitro assay. The nitrated phenolic compounds seemed to show increased anti-oxidant activity and decreased pro-oxidant activity. However, one nitrated CaA compound that has a furoxan ring showed the ability to release NO(2)(-) in the neutral condition.

Organic and inorganic dietary phosphorus and its management in chronic kidney disease.

Dietary phosphorus control is often a main strategy in the management of patients with chronic kidney disease. Dietary protein is a major source of phosphorus intake. Recent data indicate that imposed dietary phosphorus restriction may compromise the need for adequate protein intake, leading to protein-energy wasting and possibly to increased mortality. The two main sources of dietary phosphorus are organic, including animal and vegetarian proteins, and inorganic, mostly food preservatives. Animal-based foods and plant are abundant in organic phosphorus. Usually 40% to 60% of animal-based phosphorus is absorbed; this varies by degree of gastrointestinal vitamin-D-receptor activation, whereas plant phosphorus, mostly associated with phytates, is less absorbable by human gastrointestinal tract. Up to 100% of inorganic phosphorus in processed foods may be absorbed; ie, phosphorus in processed cheese and some soda (cola) drinks. A recent study suggests that a higher dietary phosphorus-protein intake ratio is associated with incremental death risk in patients on long-term hemodialysis. Hence, for phosphorus management in chronic kidney disease, in addition to absolute dietary phosphorus content, the chemical structure (inorganic versus organic), type (animal versus plant), and phosphorus-protein ratio should be considered. We recommend foods and supplements with no or lowest quantity of inorganic phosphorus additives, more plant-based proteins, and a dietary phosphorus-protein ratio of less than 10 mg/g. Fresh (nonprocessed) egg white (phosphorus-protein ratio less than 2 mg/g) is a good example of desirable food, which contains a high proportion of essential amino acids with low amounts of fat, cholesterol, and phosphorus.

Antioxidant properties, total phenols and pollen analysis of propolis samples from Portugal.

Pollen analysis, total phenols content and antioxidant activity were studied for the first time in Portuguese propolis samples from Bornes and Fundão regions. Total phenols content was determined by colorimetric assay and their amount was of 329 mg/g of GAE in Bornes sample and 151 mg/g of GAE in Fundão propolis. The antioxidant capacity of propolis extracts was assessed through the scavenging effects on DPPH (2,2-diphenyl-1-picrylhydrazyl) and reducing power of iron (III)/ ferricyanide complex assays. A concentration-dependent antioxidative capacity was verified in DPPH and reducing power assays. Low values of EC50 on DPPH scavenging assay were obtained for Bornes and Fundão propolis (of 6.22 microg/mL and 52.00 microg/mL, respectively). For reducing power the values were 9.00 microg/mL, for Bornes propolis, and 55.00 microg/mL, for Fundão propolis. The high activity of propolis from Bornes could be related with their different pollen composition. The results obtained indicate that Portuguese propolis is an important source of total phenols showing antioxidant properties that could be beneficial for human health.

Total phenols, antioxidant potential and antimicrobial activity of walnut (Juglans regia L.) green husks.

The total phenols content and antioxidant and antimicrobial activities were studied in walnut (Juglans regia L.) green husks aqueous extracts of five different cultivars (Franquette, Mayette, Marbot, Mellanaise and Parisienne). Total phenols content was determined by colorimetric assay and their amount ranged from 32.61 mg/g of GAE (cv. Mellanaise) to 74.08 mg/g of GAE t (cv. Franquette). The antioxidant capacity of aqueous extracts was assessed through reducing power assay, scavenging effects on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and beta-carotene linoleate model system. A concentration-dependent antioxidative capacity was verified in reducing power and DPPH assays, with EC50 values lower than 1 mg/mL for all the tested extracts. The antimicrobial capacity was screened against Gram positive and Gram negative bacteria, and fungi. All the extracts inhibited the growth of Gram positive bacteria, being Staphylococcus aureus the most susceptible one with MIC of 0.1 mg/mL for all the extracts. The results obtained indicate that walnut green husks may become important in the obtainment of a noticeable source of compounds with health protective potential and antimicrobial activity.

Sodium benzoate, a food additive and a metabolite of cinnamon, modifies T cells at multiple steps and inhibits adoptive transfer of experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) is the animal model for multiple sclerosis. This study explores a novel use of sodium benzoate (NaB), a commonly used food additive and a Food and Drug Administration-approved nontoxic drug for urea cycle disorders, in treating the disease process of relapsing-remitting EAE in female SJL/J mice. NaB, administered through drinking water at physiologically tolerable doses, ameliorated clinical symptoms and disease progression of EAE in recipient mice and suppressed the generation of encephalitogenic T cells in donor mice. Histological studies reveal that NaB effectively inhibited infiltration of mononuclear cells and demyelination in the spinal cord of EAE mice. Consequently, NaB also suppressed the expression of proinflammatory molecules and normalized myelin gene expression in the CNS of EAE mice. Furthermore, we observed that NaB switched the differentiation of myelin basic protein-primed T cells from Th1 to Th2 mode, enriched regulatory T cell population, and down-regulated the expression of various contact molecules in T cells. Taken together, our results suggest that NaB modifies encephalitogenic T cells at multiple steps and that NaB may have therapeutic importance in multiple sclerosis.

The depletion of sodium nitrite by lactic acid bacteria isolated from kimchi.

Nitrites, whether added or naturally occurring in foods, are potential carcinogens, and controlling their concentrations is important for maintaining a safe food supply. In this study we investigated the depletion of sodium nitrite (150 microg/mL) during the fermentation in Lactobacilli MRS broth at 5, 10, 15, 20, 25, 30, and 36 degrees C by lactic acid bacteria (LAB-A, -B, -C, and -D) isolated from kimchi and Leuconostoc mesenteroides strain KCTC3100. The four species of lactic acid bacteria isolated from kimchi were identified as L. mesenteroides, and all produced depletion of less than 20% of sodium nitrite after 10 days of incubation at 5 degrees C. There was less than 40% depletion after 9 days at 10 degrees C, 86.4-92.8% after 7 days at 15 degrees C, 81.4-87.8% after 4 days and more than 90.0% after 5 days at 20 degrees C, 76.3-85.7% after 3 days and more than 90.0% after 5 days at 25 degrees C, and more than 90.0% after 2 days at 30 and 36 degrees C. The depletion by LAB isolates was similar or higher than that by L. mesenteroides strain KCTC3100, and in particular, the LAB-D strain showed the highest depletion effect of all the strains tested, up to 15 degrees C. From these results, the strains isolated from kimchi were very effective for the depletion of sodium nitrite at high temperature, and all sodium nitrite was depleted at the initial period of incubation (1-2 days) at 30 and 36 degrees C. But as the temperature was lowered, the depletion effect of sodium nitrite was decreased in all the strains tested from kimchi. This illustrates that the depletion of nitrite by each strain is subject to the influence of temperatures.