SEARCH · PubMed Health

Results for “Food samples”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources

PubMed2003

The screening of hydrogen peroxide-producing lactic acid bacteria and their application to inactivating psychrotrophic food-borne pathogens.

Lactic acid bacteria were isolated from various food samples and evaluated for hydrogen peroxide (H2O2) production. Cells suspended in 0.5% (wt/vol) glucose plus 0.5% (wt/vol) lactate (pH 7.0) were incubated for 5 h at 37 degrees C under aeration. Among 193 strains, 27 strains accumulated 201-300 ppm H2O2, and 4 strains accumulated more than 301 ppm H2O2 in the cell suspensions. Among the 9 high-level H2O2-producing strains, 8 strains were identified as Lactococcus lactis subsp. lactis. The cell-free filtrate from Lc. lactis subsp. lactis AI 62, which contained approximately 350 ppm H2O2, was evaluated for antimicrobial activity against Enterococcus faecalis, Ent. faecium, enterotoxigenic Escherichia coli, Listeria ivanovii, Staphylococcus aureus, Yersinia enterocolitica, and Aeromonas hydrophila. After 1 h incubation at 30 degrees C in the cell-free filtrate, the initial viable cell counts of the target bacteria (5.53-6.00 log cfu/mL) were reduced by 0.12-5.00 log units, except in the case of enterococci. The sensitivity varied with the bacterial species and pH. The enterococci were resistant to the treatment. Our results show that H2O2 accumulated by lactic acid bacteria in a cell suspension is very effective in reducing the viable cell count of food-borne pathogens.

Aeromonas hydrophila↗

PubMed2002

Automated measurements of antilisterial activities of lactate and diacetate in ready-to-eat meat.

Standard procedures to enumerate Listeria organisms rely on plating food samples on selective agar media. The procedures are labor-intensive, and because of the limited sensitivity, pre-enrichment step is required for the detection of low numbers of the pathogen. In the present study, an automated rapid optic procedure and the standard procedure were used to determine the behavior of the pathogen in ready-to-eat (RTE) meat and to test the effect of antilisterial agents. Listeria monocytogenes strain Scott A or a six-strain mixture of Listeria was studied using lactate (2.5%), diacetate (0.2%) and their combination in beef bologna and in sterile beef emulsion. Samples stored for up to 60 days at 5 and 10 degrees C were tested at time intervals during storage. Using the plate count method, each of the salts caused a delay in growth of the pathogen, and the salt combination was most effective causing listeriostatic effects and decline in growth of the pathogen at 5 degrees C. High negative correlation (r), ranging from 0.92 to 0.99, was obtained between the detection time (DT) recorded by the optic procedure (BioSys instrument) and cell numbers determined by the plate count procedure. The rapid (< 24 h) optic procedure was reliable in assessing the efficacy of antimicrobials and in rapid detection of low levels of listeriae that are undetectable by direct plating procedure.

Acetates↗

PubMed2000

Oligonucleotide probe for the visualization of Escherichia coli/Escherichia fergusonii cells by in situ hybridization: specificity and potential applications.

There are several occasions when enumeration of Escherichia coli cells is needed. These include examination of urine specimens and water or food samples. Present methods rely on growth in more or less selective media (colony-forming units on agar or the most probable number method using liquid media). Unfortunately, no really selective medium with 100% efficiency of plating is available for E. coli. A 24-mer oligonucleotide probe (Colinsitu), complementary to a piece of 16S ribosomal ribonucleic acid, has been tested for specifically visualizing E. coli cells by in situ hybridization and epifluorescence microscopy. The fluorescent dye-labeled probe was able to stain cells of E. coli, Shigella spp. and E. fergusonii. Shigella spp. are known to belong to the E. coli genomospecies and E. fergusonii is the nomenspecies closest to E. coli by DNA-DNA hybridization. The probe did not stain any strain of 169 other genomospecies of the family Enterobacteriaceae or of a few other species frequently encountered in the environment. Revivification without cell division allowed the visualization of E. coli cells in contaminated water. In situ hybridization using the Colinsitu probe is a potential tool for the confirmation of (atypical) E. coli in reference centers and the rapid (3-6 h) detection and enumeration of E. coli in urine specimens, contaminated water and food. More work is needed to include in situ hybridization in laboratory routine.

Escherichia↗

PubMed2004

Regulation of interleukin-8 secretion in human intestinal epithelial Caco-2 cells by alpha-humulene.

It is well known that various cytokines such as interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha are expressed and secreted from intestinal epithelial cells and that these cytokines affect the immune cells beneath the intestinal epithelial monolayers. As the secretion of these cytokines is likely to be regulated by food-derived substances, we focused on those food substances which regulate the secretion of IL-8 in human intestinal epithelial Caco-2 cells. 72 food samples extracted with 40% ethanol were tested, and the extracts of peppermint and dokudami significantly increased the IL-8 secretion. Among the compounds known to be contained in peppermint and dokudami, alpha-humulene substantially increased the IL-8 secretion.alpha-Humulene had no significant effect on the secretion of such other soluble factors as TNF-alpha, IL-1beta, IL-6, or NGF, suggesting that the effect of alpha-humulene was specific for IL-8 secretion. The expression level of IL-8 mRNA was significantly increased by treating with alpha-humulene. These results suggest that the secretion of IL-8 by alpha-humulene is regulated at the transcriptional level.

Cell Line, Tumor↗

PubMed2000

A sandwich enzyme-linked immunosorbent assay for the detection of almonds in foods.

An enzyme-linked immunosorbent assay was developed to detect almonds as potential allergenic contaminants in food. Polyclonal antibodies directed against roasted almonds were partially purified from immunized sheep and rabbits and used as capture and secondary antibodies, respectively, in a sandwich-type, 96-well plate format. Food samples and almond-spiked samples were extracted 1:10 in phosphate-buffered saline at 60 degrees C for 2 h, centrifuged, and applied to wells coated with sheep anti-almond antibody. After incubation, washing, and the addition of rabbit anti-almond antibody, the amount of almond present was detected with the subsequent addition of goat anti-rabbit immunoglobulin G-alkaline phosphatase conjugate and p-nitrophenyl phosphate substrate. Plate absorbances were read at 410 nm, and standard curves were developed in all matrices to quantify unknowns. Antibodies developed were specific for almond; however, some cross-reactivity was observed with extracts of some tree nuts and sesame seeds. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and Western immunoblotting indicated that sheep anti-almond antibody recognized proteins extracted from black walnuts, Brazil nuts, cashews, hazelnuts, macadamia nuts, pistachios, and sesame seeds in addition to those from almond. The assay was optimized to detect less than 1 ppm of almond and was used successfully to determine almond residues in cereal and chocolate without cross-reacting interferences. A retail survey of 20 brands of cereal demonstrated that the assay produced statistically consistent results. This assay provides a useful quality control tool for the food industry for the protection of consumers allergic to almonds.

Animals↗

PubMed2005

Human exposure to metals through the diet in Tarragona, Spain: temporal trend.

The concentrations of arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), and vanadium (V) were determined in a number of food items purchased in zones of Tarragona County (Catalonia, Spain) near a hazardous waste incinerator (HWI), which has been operating since 1999. Food samples corresponded to the following groups: meat, fish and seafood, pulses, cereals, vegetables, fruits, tubers, whole milk, yogurt, eggs, and sugar. Be and Tl were under their respective limits of detection in all samples. For the analyzed trace elements, the dietary intake by the general population of Tarragona was 458.5 microg/d for As, 14.3 microg/d for Cd, 88.3 microg/d for Cr, 5.3 microg/d for Hg, 2421.4 microg/d for Mn, 138.3 microg/d for Ni, 44.8 microg/d for Pb, 34.6 microg/d for Sn, and 28.9 microg/d for V. Results were compared with those found in a baseline survey carried out in the same area during the construction of the HWI (1996-1998). In general terms, the dietary intake of metals in 2003 was comparatively similar to those found in the baseline survey. For the most toxic elements (As, Cd, Hg, and Pb), it was under their respective Provisional Tolerable Weekly Intake (PTWI) established by the FAO/WHO.

Adult↗

PubMed2004

Detection of tet(M) gene from raw milk by rapid DNA extraction followed by a two-step PCR with nested primers.

The likelihood that milk and milk products may act as a vehicle for antibiotic-resistant bacterial genes has become a concern to the food industry and a public health issue, and the demand for rapid tests has increased. The purity of DNA extracted from food samples is a key issue in the sensitivity and usefulness of biological analyses, such as PCR for pathogens and nonpathogens. A rapid, phenol-chloroform free method based on a modification of a sodium iodide DNA extraction, followed by a two-step PCR was developed for direct detection of the tet(M) gene in milk samples within a single working day. This study compares the proposed method with a traditional phenol solvent extraction method and with a commercial kit (QIAamp DNA blood mini kit, Qiagen). The three DNA extraction methods were used to ensure access to the tet(M) gene from 1 ml of raw milk, inoculated with a strain of Enterococcus faecalis, which carries the tet(M) gene. The proposed method, followed by a two-step PCR with nested primers specific for the tet(M) gene, was able to reach a detection limit below 10 CFU/ml in less than 4 h, including the two amplification cycles, thus outperforming in sensitivity and rapidity both the traditional and the commercial method.

Animals↗

PubMed2003

Thorium concentration in Pakistani diet.

To evaluate radiation doses due to ingestion of thorium activity by members of the public, baseline analytical data on thorium concentration in a typical Pakistani diet was generated. Food samples were collected from major districts/ cities of the country using the market basket method, and typical daily diets were prepared. Thorium concentration was determined by instrumental neutron activation analysis. It was found to vary from 1.6 ng g(-1) to 12 ng g(-1). The median value was 4.6 ng g(-1). This leads to median daily thorium intake of 2.7 microg d(-1). The geometric mean was 2.6 microg d(-1), which was 13% less than the ICRP value. Based on these measurements the average intake of 232Th activity was 10 mBq d(-1), and the average annual and committed effective doses for adults were estimated to be 8.8 x 10(-7) Sv y(-1) and 4.4 x 10(-5) Sv, respectively.

Diet↗

PubMed2003

Levels of polychlorinated biphenyls in foods from Catalonia, Spain: estimated dietary intake.

From June to August 2000, food samples were randomly acquired in seven cities in Catalonia, Spain. Polychlorinated biphenyl (PCB) concentrations were determined for 108 samples of vegetables, fruits, pulses, cereals, fish and shellfish, meats and meat products, eggs, milk and dairy products, and oils and fats. Levels of 11 PCB congeners (IUPAC 28, 52, 77, 101, 105, 118, 126, 138, 153, 169, and 180) were determined by high-resolution gas chromatography-high-resolution mass spectrometry. For toxic equivalent (TEQ) calculations, World Health Organization (WHO) toxicity equivalent factors (WHO-TEFs) were used. The highest levels of most congeners were found in fish and shellfish (11,864.18 ng/kg [wet weight]), and the next highest levels, which were substantially lower, were found in milk and dairy products (674.50 ng/kg [wet weight]). For the general population of Catalonia, the total dietary intake of PCBs was found to be 150.13 pg WHO-TEQ/day. The largest contribution to this intake came from fish and shellfish (82.87 pg WHO-TEQ/day) and dairy products (29.38 pg WHO-TEQ per day). A relatively large contribution was also noted for cereals (11.36 pg WHO-TEQ/day). Among the PCB congeners determined in this study, PCB 126 showed the largest contribution to total TEQ intake (50.56%). The data obtained in this study should be useful in risk assessment with regard to human PCB exposure through food in Catalonia.

Animals↗

PubMed1998

Diet, lifestyle, and the etiology of coronary artery disease: the Cornell China study.

Investigators collected and analyzed mortality data for >50 diseases, including 7 different cancers, from 65 counties and 130 villages in rural mainland China. Blood, urine, food samples, and detailed dietary data were collected from 50 adults in each village and analyzed for a variety of nutritional, viral, hormonal, and toxic chemical factors. In rural China, fat intake was less than half that in the United States, and fiber intake was 3 times higher. Animal protein intake was very low, only about 10% of the US intake. Mean serum total cholesterol was 127 mg/dL in rural China versus 203 mg/dL for adults aged 20-74 years in the United States. Coronary artery disease mortality was 16.7-fold greater for US men and 5.6-fold greater for US women than for their Chinese counterparts. The combined coronary artery disease mortality rates for both genders in rural China were inversely associated with the frequency of intake of green vegetables and plasma erythrocyte monounsaturated fatty acids, but positively associated with a combined index of salt intake plus urinary sodium and plasma apolipoprotein B. These apolipoproteins, in turn, are positively associated with animal protein intake and the frequency of meat intake and inversely associated with plant protein, legume, and light-colored vegetable intake. Rates of other diseases were also correlated with dietary factors. There was no evidence of a threshold beyond which further benefits did not accrue with increasing proportions of plant-based foods in the diet.

Adult↗

PubMed2003

Real-time application of automated ribotyping and DNA macrorestriction analysis in the setting of a listeriosis outbreak.

A cluster of three cases of listeriosis cases occurred against a background of endemic listeriosis in Western Australia. Human and environmental isolates of Listeria monocytogenes obtained during the outbreak investigation were rapidly subtyped by automated ribotyping using an EcoRI protocol and a RiboPrinter. DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) was used to confirm the relatedness of isolates. Serogroup 1/2 predominated among the food samples and the four clinical isolates from the outbreak cluster were also of this serogroup. All isolates from chicken material were serogroup 1/2 and indistinguishable by ribotype pattern. PFGE subdivided strains of this ribotype into four subtypes. The preliminary analysis had an immediate impact on hypothesis generation, environmental health investigations, environmental specimen collection and initial control measures. Sufficient typing data to guide environmental health and disease control initiatives was generated in less than one week by combining automated ribotyping with PCR-based detection of L. monocytogenes in suspect foodstuffs and an L. monocytogenes DNA probe. There were no further cases of bacteriologically confirmed listeriosis in Western Australia for six months after completion of the investigation.

Automation↗

PubMed2004

Evaluation of large volume-difficult matrix introduction-gas chromatography-time of flight-mass spectrometry (LV-DMI-GC-TOF-MS) for the determination of pesticides in fruit-based baby foods.

The European Union Baby Food Directive (1999/39/EC), which came into force on 1 July 2002, set legal maximum residue levels at 0.01 mg kg(-1) for all pesticides in baby foods. The combination of large volume-difficult matrix introduction (LV-DMI) with gas chromatography-time of flight-mass spectrometry (GC-TOF-MS), described herein, provides the analyst with a simple but rapid alternative GC-MS technique for the multiresidue analysis of pesticides in fruit-based baby foods. Samples were extracted with ethyl acetate in the presence of Na2SO4 and NaHCO3 and the crude extracts were analysed directly using LV-DMI-GC-TOF-MS. The best overall results (98 pesticides quantified satisfactorily at a spiking level of 0.01 mg kg(-1)) were obtained by analysis of concentrated extracts (2.5 g crop ml(-1)) using a 30-m column, with a chromatographic run time of 25 min. A good signal-to-noise ratio was obtained at the lowest calibrated level (0.0125 microg ml(-1)), with excellent linearity achieved over the range 0.0125-0.25 microg ml(-1) (equivalent to 0.005-0.1 mg kg(-1)). Average recoveries for the analysis of five replicate determinations at a spiking level of 0.01 mg kg(-1) were between 79 and 114% with relative standard derivations generally less than 20%.

Calibration↗

PubMedDate not supplied

Recovery of 1,3-, 2,3-dichloropropenes, 1,2-dibromo-3-chloropropane, and o-, p-dichlorobenzenes from fatty and non-fat foodstuffs by liquid extraction technique.

Food samples including fatty, non-fatty, grain-based, and nongrain-based types were fortified with the following five nematocides and fumigants: 1,3-dichloropropene, 2,3-dichloropropene, 1,2-dibromo-3-chloropropane, o-dichlorobenzene, and p-dichlorobenzene. Then, depending on sample consistency and type, the samples were diluted in, or extracted with organic solvent such as isooctane. A few of the high-fat extracts were passed through Florisil to remove excess fat or endogenous interferences. Analysis of the initial or cleaned up extracts was done by gas chromatography (GC) at 90 degrees C. The dichloropropenes were determined on 20% OV-101 columns with electron-capture and Hall electroconductivity detectors. The dichlorobenzenes and 1,2-dibromo-3-chloropropane, which elute beyond 30 min on the above columns, were determined on 5%-loaded columns using the same detectors. All five analytes were recovered from these techniques. Mean analyte recovery following a direct dilution or extraction was 83%, and following the Florisil cleanup step, was 52%. In 1986, a fumigant survey of about 200 foodstuffs by using this overall technique gave no findings of the five compounds studied here.

Allyl Compounds↗

PubMed2004

Recommended methods of fatty acid methylester preparation for conjugated dienes and trienes in food and biological samples.

In this study, we compared three acid-catalyzed methods and three base-catalyzed methods for the methylester preparation of conjugated dienoic fatty acids and conjugated trienoic fatty acids in food and biological samples. Among the six methods examined, the sodium methoxide/methanol (NaOCH3/MeOH) method and the tetramethylguanidine/ methanol (TMG/MeOH) method of methylester preparation from tung oil were most efficient in preventing the artificial isomerization of alpha-eleostearic acid (alpha-ESA; 9c,11t,13t-18:3) to beta-eleostearic acid (beta-ESA: 9t,11t,13t-18:3) and for avoiding the artificial generation of unknown byproducts. Hydrochloric acid/methanol (HCl/MeOH), sulfuric acid/methanol (H2SO4/MeOH) and AOCS (boron trifluoride/methanol (BF3/MeOH)) methods of methylester preparation from tung oil resulted in the breakdown of alpha-ESA due to their long reaction periods and high reaction temperatures. In addition, these three methods did not prevent the generation of beta-ESA. For the methylester preparation of tung oil free fatty acids, the BF3/MeOH method (30 min at room temperature) did not lead to artificial beta-ESA formation or byproducts, while the trimethylsilyldiazomethane (TMSN2CH3) method did form artifacts. For the methylation of conjugated linoleic acid (CLA, free fatty acid), the BF3/ MeOH and TMSN2CH3 methods completely suppressed artificial isomerization of c,t-CLA and t,c-CLA to t,t-CLA. The results indicated that the BF3/MeOH method for free fatty acids is the best method for the methylester preparation of both conjugated dienoic and trienoic fatty acids with respect to preventing artificial isomerization and the formation of byproducts. The BF3/MeOH method was applicable to both food and biological samples.

Aleurites↗

PubMed2005

Speciation of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Multiple strains of Campylobacter coli, C. jejuni, C. helveticus, C. lari, C. sputorum, and C. upsaliensis isolated from animal, clinical, or food samples have been analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Whole bacterial cells were harvested from colonies or confluent growth on agar and transferred directly into solvent and then to a spot of dried 3-methoxy-4-hydroxycinnamic acid (matrix). Multiple ions in the 5,000- to 15,000-Da mass range were evident in spectra for each strain; one or two ions in the 9,500- to 11,000-Da range were consistently high intensity. "Species-identifying" biomarker ions (SIBIs) were evident from analyses of multiple reference strains for each of the six species, including the genome strains C. jejuni NCTC 11168 and C. jejuni RM1221. Strains grown on nine different combinations of media and atmospheres yielded SIBI masses within +/-5 Da with external instrument calibration. The highest-intensity C. jejuni SIBIs were cytosolic proteins, including GroES, HU/HCj, and RplL. Multiple intraspecies SIBIs, corresponding probably to nonsynonymous nucleotide polymorphisms, also provided some intraspecies strain differentiation. MALDI-TOF MS analysis of 75 additional Campylobacter strains isolated from humans, poultry, swine, dogs, and cats revealed (i) associations of SIBI type with source, (ii) strains previously speciated incorrectly, and (iii) "strains" composed of more than one species. MALDI-TOF MS provides an accurate, sensitive, and rapid method for identification of multiple Campylobacter species relevant to public health and food safety.

Animals↗

PubMed2002

Applicability of the draft standard method for the detection of Escherichia coli O157 in dairy products.

According to the draft standard method, EN ISO 16654 for the detection of Escherichia coli O157 in foods, samples of milk products inoculated with E. coli O157 were cultured in modified Tryptone Soya Broth supplemented with novobiocin. After immuno-magnetic separation (IMS) of the micro-organisms with magnetic beads coated with an antibody against E. coli O157 (Dynabeads anti E. coli O157, Dynal), the enrichment broth was subcultured onto both Cefixim Tellurite Sorbitol MacConkey agar and CHROMagar O157. IMS alone appeared not to be very specific to E. coli O157; however, IMS combined with CT-SMAC plating enabled a greater exclusivity. The method displayed a low limit of detection (1-2 cfu/25 g) of E. coli O157 strains in milk products after only 6 h of incubation of the enrichment broth. However, the detection was affected by storage of the inoculum at 4 degrees C, and another 12 to 18 h of incubation was necessary to recover potentially stressed cells.

Animals↗

PubMed1992

Nonspecific reactions of a commercial enzyme-linked immunosorbent assay kit (TECRA) for detection of staphylococcal enterotoxins in foods.

A staphylococcal enterotoxin visual immunoassay kit (TECRA) has recently become commercially available. Since the kit is an enzyme-linked immunosorbent assay system equipped with polyvalent antisera against staphylococcal enterotoxin types A to E (SEA to SEE) and the test is simple and rapid to perform (4 h), it has been widely used for screening purposes. In this study, the sensitivity of the kit for detection of SEA, SEB, and SEC in ham, cheese, and mushrooms was similar to those of kits based on an enzyme immunoassay and reversed passive latex agglutination: 0.75 to 1.0 ng of SEA per ml, 0.5 to 0.75 ng of SEB per ml, and 1.0 to 1.25 ng of SEC per ml. However, the TECRA kit showed nonspecific reactions with food samples contaminated by microorganisms other than Staphylococcus aureus, such as Enterobacter agglomerans, Enterobacter cloacae, Proteus mirabilis, Pseudomonas aeruginosa, and Serratia marcescens. The substance contributing to the false-positive results differed from true staphylococcal enterotoxins in that it was (i) heat labile (completely inactivated by heating for 2 min at 100 degrees C, whereas true staphylococcal enterotoxins were inactivated by about 10% with this treatment), (ii) lower in molecular weight than staphylococcal enterotoxins, and (iii) not bound to a copper chelate Sepharose gel (all of the substance remained in the unbound wash fraction, whereas staphylococcal enterotoxins were quantitatively bound to the gel). The problem of false-positive results with the TECRA kit could be resolved by heat treatment (2 min at 100 degrees C) or by cleanup procedures involving metal chelate affinity chromatography with copper chelate Sepharose for 4 h before use of the TECRA kit.

Enterotoxins↗

PubMed2003

Synergistic interaction between aflatoxin B1 and hepatitis B virus in hepatocarcinogenesis.

Chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1), two of the major risk factors in the multifactorial aetiology of hepatocellular carcinoma (HCC), co-exist in those countries with the highest incidences of and the youngest patients with this tumour, raising the possibility of a synergistic carcinogenic interaction between the two agents. Experimental studies in HBV-transgenic mice and woodchucks infected with woodchuck hepatitis virus were the first to show a synergistic hepatocarcinogenic effect between hepadnaviral infection and AFB1 exposure. With the availability of urinary and serum biomarkers that more accurately reflect dietary exposure to AFB1 than did the initially used food sampling and dietary questionnaires, cohort studies of patients with HCC in China and Taiwan have provided compelling evidence for a multiplicative or sub-multiplicative interaction between HBV and AFB1 in the genesis of human HCC. A number of possible mechanisms for the interaction have been suggested. Chronic HBV infection may induce the cytochrome P450s that metabolise inactive AFB1 to the mutagenic AFB1-8,9-epoxide. Hepatocyte necrosis and regeneration and the generation of oxygen and nitrogen reactive species resulting from chronic HBV infection increase the likelihood of the AFB1-induced p53 249ser and other mutations and the subsequent clonal expansion of cells containing these mutations. Nuclear excision repair, which is normally responsible for removing AFB1-DNA adducts, is inhibited by HBV x protein, favouring the persistence of existing mutations. This protein also increases the overall frequency of DNA mutations, including the p53 249ser mutation, and may contribute to uncontrolled cell cycling when p53 is non-functional.

Aflatoxin B1↗