Aronia melanocarpa (Michx.) Elliot, Chaenomeles superba Lindl. and Cornus mas L. Leaf Extracts as Natural Preservatives for Pork Meat Products.

The aim of this study was to investigate the possibility of using Aronia melanocarpa, Chaenomeles superba, and Cornus mas leaf extracts as natural preservatives for pork meat products. Pork sausages were stored in modified atmosphere packaging (MAP) (80% N2 and 20% CO2) at 4 °C for 29 days. The total psychrotrophic counts (TPC) were determined during the storage period, along with the numbers of Enterobacteriaceae and lactic acid bacteria (LAB). The extracts improved the microbial quality of the meat products but to a lesser extent than sodium nitrate (III). They reduced the amounts of Enterobacteriaceae and LAB. The A.melanocarpa leaf extract showed the strongest preservative effect. The bacterial biodiversity of the meat products was investigated based on high-throughput sequencing of the 16S rRNA gene. Two predominant bacteria phyla were identified, Proteobacteria and Firmucutes, mostly consisting of genera Photobacterium, Brochothrix, and Carnobacterium. The extracts also influenced microbial community in sausages decreasing or increasing bacterial relative abundance. The extracts significantly inhibited lipid oxidation and improved the water-holding capacity of the meat, with C. superba extract showing the strongest influence. In addition, A. melanocarpa and C. superba improved the redness (a*) of the sausages. The results of this study show that A. melanocarpa, C. superba, and C. mas leaf extracts can extend the shelf life of meat products stored in MAP at 4 °C.

Antibacterial mechanisms of Aronia melanocarpa (Michx.), Chaenomeles superba Lindl. and Cornus mas L. leaf extracts.

The aim of this study was to investigate the in vitro antibacterial mechanisms of Aronia melanocarpa, Chaenomeles superba, and Cornus mas leaf extracts towards meat spoilage and pathogenic bacteria. The extracts decreased bacterial viability after 24 h and 48 h of incubation. Acting as prooxidants, the extracts induced intracellular ROS (reactive oxygen species) generation in bacteria cells, with C. mas having the strongest influence. The leaf extracts increased the release of UV intracellular absorbing components, suggesting a reduction in membrane integrity. They also increased the outer-membrane permeability of the Gram-negative bacteria, with C. superba extract being the most active. Following exposure to the leaf extracts, morphological changes in the bacteria were observed, including the formation of aggregates, EPS synthesis, irregular forms, wrinkled cell surfaces, pores in the cell wall, and shriveling of cells. The leaf extracts inhibited DNA synthesis in E. coli cells by suppressing DNA gyrase activity.

Plant extracts rich in polyphenols: antibacterial agents and natural preservatives for meat and meat products.

Plant extracts contain large amounts of bioactive compounds, mainly polyphenols. Polyphenols inhibit the growth of microorganisms, especially bacteria. Their mechanism of action is still not fully understood but may be related to their chemical structure. They can cause morphological changes in microorganisms, damage bacterial cell walls and influence biofilm formation. Polyphenols also influence protein biosynthesis, change metabolic processes in bacteria cells and inhibit ATP and DNA synthesis (suppressing DNA gyrase). Due to the antioxidant and antibacterial activity of phenolic compounds, plant extracts offer an alternative to chemical preservatives used in the meat industry, especially nitrates (III). They can inhibit the growth of spoilage and pathogenic microflora, suppress oxidation of meat ingredients (lipids and proteins) and prevent discoloration. In this paper, we describe the factors that influence the content of polyphenols in plants and plant extracts. We present the antimicrobial activities of plant extracts and their mechanisms of action, and discuss the effects of plant extracts on the shelf-life of meat and meat products.

Characterization of Phytochemicals in Berry Fruit Wines Analyzed by Liquid Chromatography Coupled to Photodiode-Array Detection and Electrospray Ionization/Ion Trap Mass Spectrometry (LC-DAD-ESI-MSn) and Their Antioxidant and Antimicrobial Activity.

Fruits are a valuable source of phytochemicals. However, there is little detailed information about the compounds contained in fruit wines. In this study, wines from six different berries were analyzed using HPLC-DAD-ESI-MSn. About 150 compounds were identified, including anthocyanins (34), hydroxycinnamic acids (12) and flavonols (36). Some of the compounds were identified for the first time in berry wines. The blackberry wines were found to contain the largest number of bioactive compounds (59). Elderberry wines where the richest source of polyphenols (over 1000 mg/L) and contained the largest amounts of all of the analyzed groups of compounds (hydroxycinnamic acids, anthocyanins and flavonols). The lowest concentration of polyphenols was observed in the wines made from cranberries and bilberries (less than 500 mg/L). The antioxidant activity was determined in relation to ABTS+, DPPH, and FRAP. The highest values were observed in the blackberry wines, and the lowest for the cranberry wines. The wines were analyzed to test their antimicrobial activity. Five of the six wines (with the exception of elderberry wine) inhibited Bacillus cereus growth and two (blackberry and cranberry wines) were active against Listeria monocytogenes.

The Profiles of Low Molecular Nitrogen Compounds and Fatty Acids in Wort and Beer Obtained with the Addition of Quinoa (Chenopodium quinoa Willd.), Amaranth (Amaranthus cruentus L.) or Maltose Syrup.

Replacement of a part of malt with unmalted materials is a common practice in beer production. These materials may differ in chemical composition than barley malt, which in turn can contribute to changes in the final composition of the wort. Consequently, it may affect yeast metabolism and final parameters of the obtained products. In this research, two unmalted pseudocereals were used: quinoa (Chenopodium quinoa Willd.) and amaranth (Amaranthus cruentus L.). Maltose syrup was tested as a reference material due to its commercial usage as a substitute of malt in production of worts. Replacement of a part of the malt with quinoa or amaranth favorably influenced the profiles of amino and fatty acids. Due to the fact that the type and concentration of individual amino acids and fatty acids in the fermented wort significantly affect the flavor compounds synthesized by yeast, differences in the profiles of esters and higher alcohol have been noted in beers produced with pseudocereals.

Composition and Antibacterial Activity of Aronia melanocarpa (Michx.) Elliot, Cornus mas L. and Chaenomeles superba Lindl. Leaf Extracts.

The purpose of this study was to investigate the composition of leaf extracts from Aronia melanocarpa, Chaenomeles superba, and Cornus mas, and their antimicrobial activity against typical spoilage-causing and pathogenic bacteria found in meat and meat products. The highest total phenolic content (TPC) was detected in C. superba extract, followed by C. mas and A. melanocarpa extracts. The antioxidant capacity of the extracts was measured by DPPH and ABTS assays. The lowest IC50 values were found for C. superba extract, followed by C. mas and A. melanocarpa extracts. LC-MS and HPLC analysis revealed that A. melanocarpa and C. superba extracts contained hydroxycinnamic acid derivatives and flavonoids (mainly flavonols). Hydroxycinnamic acid derivatives were detected in the C. mas extract, as well as flavonols, ellagitannins, and iridoids. The antibacterial activity of the plant extracts was tested against Gram-negative bacteria (Moraxella osloensis, Pseudomonas fragi, Acinetobacter baumanii, Escherichia coli, Enterobacter aerogenes, Salmonella enterica) and Gram-positive bacteria (Enterococcus faecium, Staphylococcus aureus, Brochothrix thermosphacta, Lactobacillus sakei, Listeria monocytogenes) using the microculture method. The extracts acted as bacteriostatic agents, decreasing the growth rate (µmax) and extending the lag phase (tlag). C. mas showed most potent antibacterial activity, as confirmed by principal component analysis (PCA).

Structurally Different Pectic Oligosaccharides Produced from Apple Pomace and Their Biological Activity In Vitro.

This study set out to identify the composition and the biological activity of pectin-derived oligosaccharides (POS) generated from mild acid or enzymatic hydrolysis of apple pomace (AP). The effect of the polymerization of the structural units of POS contained in the AP hydrolysate on the growth and metabolism of microbiota from the human gastrointestinal tract and the adhesion of lactic acid bacteria (LAB) or pathogens to human gut epithelial cells was investigated in vitro. Mild acid hydrolysis followed by pectinolysis with Rohapect MaPlusT yielded the highest concentration of POS. In contrast, pure enzymatic processing of the AP performed with a mixed preparation of cellulase and Rohapect MaPlusT resulted in 1.8-fold lower overall POS. The concentration of higher-order oligosaccharides (degree of polymerization (DP) 7-10), however, was 1.7-fold higher. The increased ratio of higher-order oligosaccharides caused an increase in the bifidogenic effect, as well as affecting the amount and nature of short-chain fatty acid produced. Inhibition of Enterobacteriaceae was also observed. The strongest stimulation of LAB adhesion to the human epithelial cells occurred in the presence of the preparation containing the highest concentration of higher-order oligosaccharides. The fecal bacteria and pathogens showed much weaker adhesion to intestinal cells in the presence of all the tested AP hydrolysates. Both of the tested POS preparations, containing structurally different oligosaccharides (DPs 2-10 with different ratios of higher-order oligosaccharides), have the potential to be used as prebiotics for humans and animals. They stimulate bowel colonization with lactic acid bacteria and inhibit the development of infections caused by pathogens.

Activity of Mentha piperita L. Ethanol Extract against Acetic Acid Bacteria Asaia spp.

Acetic acid bacteria belonging to the genus Asaia spp. are relatively new microbial contaminants in the beverage industry. These bacteria cause organoleptic changes such as increased turbidity, haziness and sour odor. In addition, they are able to form biofilms on the inner parts of production lines, and finally they can cause secondary contamination of final products. For this reason, new methods using effective and safe preservatives are being developed to improve microbial stability of soft beverages. The aim of the research was to investigate the effects of Mentha piperita L. ethanol extract against Asaia spp. biofilm formation. The bacterial adhesion was evaluated by a plate count method and luminometry, as well as fluorescence microscopy. The polyphenolic profile of the mint extract was determined on the basis of high-performance liquid chromatography (HPLC). The obtained microbiological results indicate bacteriostatic effect of mint extract at 10% (v/v) concentration. The plant extract also reduces the number of adhered bacterial cells on polystyrene surface.

Food waste co-digestion with slaughterhouse waste and sewage sludge: Digestate conditioning and supernatant quality.

In this study, the anaerobic mesophilic co-digestion of food waste (FW) with municipal sewage sludge (MSS) and slaughterhouse waste (SHW) was undertaken in 3-dm3 laboratory reactors as well as in 50-dm3 reactors operated in semi-continuous conditions. The highest methane yield of around 0.63 m3 CH4/kgVSfed was achieved for the mixture of FW and SHW treated in the laboratory digester operated at solids retention time (SRT) of 30 days, whereas the co-digestion of FW with MSS under similar operating conditions produced 0.46 m3 of methane from 1 kgVSfed. No significant differences between methane yields from laboratory digesters and large-scale reactors were reported. The conditioning tests with the digestates from reactor experiments revealed the highest efficiency of inorganic coagulants among all investigated chemicals, which applied in a dose of 10 g/kg allowed to reduce capiliary suction time (CST) of the digestate below 20 s. The combined conditioning with coagulants and bentonite did not further reduce the CST value but improved the quality of the digestate supernatant. In particular, the concentrations of suspended solids, COD as well as metals in the supernatant were considerably lowered.

The Effect of Different Starch Liberation and Saccharification Methods on the Microbial Contaminations of Distillery Mashes, Fermentation Efficiency, and Spirits Quality.

The aim of this study was to evaluate the influence of different starch liberation and saccharification methods on microbiological contamination of distillery mashes. Moreover, the effect of hop α-acid preparation for protection against microbial infections was assessed. The quality of agricultural distillates was also evaluated. When applying the pressureless liberation of starch (PLS) and malt as a source of amylolytic enzymes, the lactic acid bacteria count in the mashes increased several times during fermentation. The mashes obtained using the pressure-thermal method and malt enzymes revealed a similar pattern. Samples prepared using cereal malt exhibited higher concentrations of lactic and acetic acids, as compared to mashes prepared using enzymes of microbial origin. The use of hop α-acids led to the reduction of bacterial contamination in all tested mashes. As a result, fermentation of both mashes prepared with microbial origin enzyme preparations and with barley malt resulted in satisfactory efficiency and distillates with low concentrations of aldehydes.

Suitability of the probiotic lactic acid bacteria strains as the starter cultures in unripe cornelian cherry (Cornus mas L.) fermentation.

This study examines the influence of lactic acid fermentation on iridoid and polyphenolic compounds in unripe Cornus mas L. fruits. Fermentation was carried out at room temperature over 6 weeks. Eight versions of the fermentation process were conducted: with inoculation by microflora isolated from black olives, Lb. brevis 18 M, Lb. casei 0919, Lb. paracasei 920, Lb. rhamnosus 0900, Lb. rhamnosus 0908, and spontaneous fermentation with and without summer savory (Satureja hortensis). The polyphenolic compounds, iridoids and antioxidant activities were examined in the products obtained. After fermentation, the polyphenols detected were: gallic acid and one of its derivatives, protocatechuic and ellagic acids, neochlorogenic and chlorogenic acids, and a chlorogenic acid derivative. Loganic acid and cornuside were found to be present in both the fermented fruits and the brines. The tested microorganisms produced varying amounts of lactic acid and had varying degrees of impact on the content of biologically active compounds. Lb. rhamnosus 908 proved to be the most effective strain. Unripe cornelian cherries fermented with probiotic strains could be used as an innovative pro-health product.

Phenolic Compounds Contained in Little-known Wild Fruits as Antiadhesive Agents Against the Beverage-Spoiling Bacteria Asaia spp.

The aim of the study was to evaluate antioxidant activity and total phenolic content of juice from three different types of fruits: elderberry (Sambucusnigra), lingonberry (Vacciniumvitis-idaea) and cornelian cherry (Cornusmas), and their action against adhesion of bacterial strains of Asaialannensis and Asaiabogorensis isolated from spoiled soft drinks. The antioxidant profiles were determined by total antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl, DPPH), and ferric-reducing antioxidant power (FRAP). Additionally, total polyphenol content (TPC) was investigated. Chemical compositions of juices were tested using the chromatographic techniques: high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Adhesion properties of Asaia spp. cells to various abiotic materials were evaluated by luminometry, plate count and fluorescence microscopy. Antioxidant activity of fruit juices expressed as inhibitory concentration (IC50) ranged from 0.042 ± 0.001 (cornelian cherry) to 0.021 ± 0.001 g/mL (elderberry). TPC ranged from 8.02 ± 0.027 (elderberry) to 2.33 ± 0.013 mg/mL (cornelian cherry). Cyanidin-3-sambubioside-5-glucoside, cyanidin-3-glucoside, and cyanidin-3-sambubioside were detected as the major anthocyanins and caffeic, cinnamic, gallic, protocatechuic, and p-coumaric acids as the major phenolic acids. A significant linear correlation was noted between TPC and antioxidant capacity. In the presence of fruit juices a significant decrease of bacterial adhesion from 74% (elderberry) to 67% (lingonberry) was observed. The high phenolic content indicated that these compounds may contribute to the reduction of Asaia spp. adhesion.

Structural, physicochemical and biological properties of spray-dried wine powders.

Different fruit wines, chokeberry, blackcurrant and blueberry, were spray-dried using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and inulin (IN). The structural, physicochemical, and biological properties of the spray-dried wine powders were studied over 12months of storage in darkness at 8°C. Identification and quantification of single phenolic compounds before and after storage revealed that HP-ß-CD had a positive effect on anthocyanin retention during storage for all microcapsules tested. Similar decreases in anthocyanin were found for blackcurrant and chokeberry powders, ranging from 7.3 to 8.9% with HP-ß-CD and 12.3 to 12.5% with IN. Levels of anthocyanin losses in blueberry wine microcapsules were much greater: 19.9% (HP-ß-CD) and 22.7% (IN). The high antiradical activities of blackcurrant and chokeberry wine microcapsules were stable and remained unchanged during storage. All wine microcapsules revealed significant activity against medically important bacterial strains. The HP-ß-CD samples showed generally higher activity against the test microorganisms compared to IN microcapsules, especially at concentrations of 100mg/mL.

Antibacterial and Antiadhesive Activities of Extracts from Edible Plants against Soft Drink Spoilage by Asaia spp.

This study was conducted to investigate the antibacterial and antiadhesive activities of ethanol extracts from five edible plant parts: cinnamon bark ( Cinnamomum zeylanicum ), licorice root ( Glycyrrhiza radix ), nettle leaves ( Urtica dioica ), green tea leaves ( Camellia sinensis ), and elderberry flowers ( Sambucus nigra ). The chemical constituents of the extracts were identified using high-performance liquid chromatography and liquid chromatography plus mass spectrometry. Six strains of Asaia lannensis and Asaia bogorensis bacteria isolated from spoiled commercial fruit-flavored noncarbonated mineral water were used. Bacterial adhesion to polystyrene as an attachment substrate in culture media supplemented with 10% plant extract was evaluated using luminometric measurement of the ATP extracted from adhered cells. The viability of the adhered and planktonic cells was assessed using the plate count method, and the relative adhesion coefficient was calculated. All tested crude extracts contained flavonols (kaempferol, quercetin, and their derivatives), flavanols (catechin and derivatives), flavanones (glabrol, licorice glycoside A, and liquiritin), and phenolic acids (gallic, quinic, chlorogenic, neochlorogenic, caffeic, coumaric, and ferulic). The culture medium with 10% elderberry extract provided the least favorable environment for all tested bacterial strains. Extracts from green tea, cinnamon, and licorice also had significant inhibitory effects on the adhesion of the tested bacterial strains. This research suggests that the addition of selected edible plant extracts could improve the microbial stability of noncarbonated soft drinks.

Black Currant (Ribes nigrum L.) and Bilberry (Vaccinium myrtillus L.) Fruit Juices Inhibit Adhesion of Asaia spp.

The aim of the study was to evaluate the activity of high-polyphenolic black currant (Ribes nigrum L.) and bilberry (Vaccinium myrtillus L.) juices against bacterial strains Asaia lannensis and Asaia bogorensis isolated as spoilage of commercial soft drinks. The composition of fruit juices was evaluated using chromatographic techniques HPLC and LC-MS. The adhesion to glass, polystyrene, and polyethylene terephthalate in two different culture media was evaluated by luminometry and the plate count method. The major anthocyanins in the V. myrtillus were petunidin-3-glucoside, malvidin-3-glucoside, cyanidin-3-glucoside, and delphinidin-3-glucoside, while in R. nigrum delphinidin-3-rutinoside and cyanidin-3-rutinoside were detected. The LC-MS analysis showed presence of anthocyanins (delphinidin, cyanidin, petunidin, and malvidin derivatives), phenolic acids (chlorogenic and neochlorogenic acids), flavonols (quercetin-3-glucoside, quercetin-3-rutinoside), and flavanols (procyanidin B2 and procyanidin type A2). Additionally, in the bilberry juice A type procyanidin trimer was detected. The adhesion of Asaia spp. cells depended on the type of medium, carbon sources, and the type of abiotic surfaces. We noted that the adhesion was significantly stronger in minimal medium containing sucrose. The addition of bilberry and black currant juices notably reduced bacterial growth as well as cell adhesion to polyethylene terephthalate surfaces.

Polyphenolic extracts of cherry (Prunus cerasus L.) and blackcurrant (Ribes nigrum L.) leaves as natural preservatives in meat products.

The objective of this study was to evaluate the possibility of using polyphenolic extracts from cherry and blackcurrant leaves as natural antimicrobial agents in meat products. The polyphenolic composition of the extracts was analyzed and their impact on the microbial quality, lipid oxidation, color, and sensory evaluation of pork sausages was studied. Polyphenolic extracts were obtained from leaves collected in September. The total polyphenolic content in sour cherry leaf extract was 1.5 times higher than that found in blackcurrant leaf extract. Analysis of the polyphenol profile of each extract revealed two major groups: phenolic acids and flavonoids, including epigallocatechin and glycosides of quercetin and kaempferol. After chilling the sausages for 14 and 28 days, the extracts caused significantly lower MDA generation, indicating an antioxidant effect. Color changes after 28 days of storage were perceptible in the case of all treatments, with and without polyphenols. The application of sour cherry and black currant leaf extracts increased the shelf life of vacuum-packed sausages. Both extracts enhanced the microbial quality of the pork sausages over 14 days of refrigerated storage. Sour cherry leaf polyphenols were more effective against almost all studied groups of microorganisms.

Prebiotics and age, but not probiotics affect the transformation of 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) by fecal microbiota - An in vitro study.

Heterocyclic aromatic amines (HAAs) are carcinogens which are formed in meat cooked using high-temperature methods. The human gastrointestinal (GI) microbiota plays a crucial role in maintaining health in humans of different ages, and especially in the elderly. However, the GI microbiota, whose metabolism and composition changes with age, may also be responsible for the activation of mutagenic substances reaching the colon with diet. Probiotics and prebiotics are promising in terms of reducing the destructive effects of HAAs. The aim of the study was to determine if fecal microbiota derived from the feces of 27 volunteers: infants (up to 18 months), adults (aged 23-39 years), the sub-elderly (aged 64-65 years), and the elderly (aged 76-87 years), and the presence of probiotics or prebiotics, affected the transformation of IQ (2-amino-3-methylimidazo[4,5-f]quinoline) to 7-OH-IQ (2-amino-3,6-dihydro-3-methyl-7H-imidazo[4,5-f]quinoline-7-one). The compounds were identified using LC-MS(n), NMR, and FTIR. Their genotoxicity was compared in the comet assay. Individual strains capable of IQ transformation were also identified. 7-OH-IQ was detected in six persons (two children and four elderly individuals). The degree of IQ conversion ranged from 26% (4-month-old girl) to 94% (81-year-old woman) of the initial quantity. Four Enterococcus isolates: two Enterococcus faecium and two Enterococcus faecalis strains, as well as one Clostridium difficile strain (LOCK 1030, from the culture collection) converted IQ to 7-OH-IQ. The genotoxicity of samples containing 7-OH-IQ was even three times higher (P < 0.05) than those with IQ and was correlated with the degree of IQ conversion and 7-OH-IQ concentration.

The Impact of Ozone Treatment in Dynamic Bed Parameters on Changes in Biologically Active Substances of Juniper Berries.

The development of the parameters of ozone decontamination method assuring the least possible losses of biologically active substances (essential oils and polyphenols) and their activity in common juniper (Juniperus communis (L.)) berries was studied. Ozone treatment in dynamic bed was conducted 9 times. The process was conducted under different ozone concentrations (100.0; 130.0; 160.0 g O3/m3) and times (30, 60, 90 min). After each decontamination, the microbiological profile of the juniper berries was studied, and the contaminating microflora was identified. Next to the microbiological profile, the phenolic profile, as well as antioxidant activity of extracts and essential oils were determined. The total polyphenol content (TPC), composition of essential oils, free radical-scavenging capacity, total antioxidant capacity, ferric-reducing antioxidant power (FRAP), beta-carotene bleaching test (BCB) and LC-MS polyphenol analysis were carried out. The study reveals that during short ozone contact times, higher amounts of TPC, 15.47 and 12.91 mg CE/g of extract, for samples 100/30 and 130/30, respectively, were demonstrated. Whereas samples 100/60, 130/60, 100/90, and 160/90 exhibited the lowest amount of phenolics. The highest antioxidant activity was found in the methanol extract obtained from ozonated berries which exhibited the lowest IC50 in all the antioxidant assays, such as DPPH, FRAP, and BCB assays. Ozone treatment showed noteworthy potential and its usage in food manufacturing and as an alternative decontamination method should be considered.

Influence of silver nanoparticles on metabolism and toxicity of moulds.

The unique antimicrobial features of silver nanoparticles (AgNPs) are commonly applied in innumerable products. The lack of published studies on the mechanisms of AgNPs action on fungi resulted in identification of the aim of this study, which was: the determination of the influence of AgNPs on the mould cytotoxicity for swine kidney cells (MTT test) and the production of selected mycotoxins, organic acids, extracellular enzymes by moulds. The conducted study had shown that silver nanoparticles can change the metabolism and toxicity of moulds. AgNPs decrease the mycotoxin production of Aspergillus sp. (81-96%) and reduce mould cytotoxicity (50-75%). AgNPs influence the organic acid production of A. niger and P. chrysogenum by decreasing their concentration (especially of the oxalic and citric acid). Also, a change in the extracellular enzyme profile of A. niger and P. chrysogenum was observed, however, the total enzymatic activity was increased.

Protective activity of probiotic bacteria against 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine (PhIP) - an in vitro study.

Heterocyclic aromatic amines (HAAs) are carcinogenic compounds present in a typical Western diet rich in thermally processed meat. These nutritional factors can modulate the cytotoxicity of faecal water (FW) and induce tumours in the human gastrointestinal tract. Supplementation with probiotics is promising in terms of reducing the harmful effects of HAAs in the human body. The aim of the study was in vitro assessment of the protective activity of the probiotic strains Lb. rhamnosus 0900, Lb. rhamnosus 0908, Lb. casei 0919 and Lb. casei DN 114001 against IQ (2-amino-3-methyl-3H-imidazo[4,5-f]quinoline) and PhIP (2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine) after incubation with faeces from 15 persons aged 4 months to 82 years (children, adults and the elderly). The highest mean cytotoxicity of FW was observed for the elderly (63.2% ± 3.7%) and the lowest for children (28.0% ± 9.5%), as estimated by a neutral red uptake assay. The probiotics lowered the average cytotoxicity of FW exposed to IQ or PhIP. The concentration of IQ and PhIP in FW was most effectively reduced by Lb. rhamnosus 0900 (47.5%) and Lb. casei 0919 (45.8%), respectively, as determined by high -performance liquid chromatography. All the tested strains bound PhIP to a higher extent than IQ. In an alkaline comet assay, Lb. casei 0919 and Lb. rhamnosus 0908 displayed the strongest protective effect against IQ and PhIP (up to 80% reduction of DNA damage). Also in a comet assay, Lb. rhamnosus 0908 exhibited antioxidative activity toward H2O2 and PhIP (up to 63% and 69.5% reduction of oxidative DNA damage, respectively). The protective activity of the probiotic strains was specific to a given person's FW, which implies the involvement of intestinal microbiota in the process.