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PubMed2004

Mineral content of water and food in fluorotic villages and prevalence of dental fluorosis.

The fluoride (F), calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), and phosphorus (P) content in potable water and food samples from endemic and nonendemic villages for fluorosis were analyzed. It was found that the F content in water was significantly higher (p<0.01) in endemic villages (4.20+/-1.6 ppm) than control villages (0.63+/-0.15 ppm), whereas the Ca, Cu, and Mg contents were found to be significantly lower (p<0.05) in endemic villages compared to control villages. However, there was no significant difference in Zn and P contents between the villages. Foods grown in endemic villages contained significantly higher (p<0.01) fluoride content as compared to control villages. There was no significant difference in Ca, Mg, P, and Zn contents in food grown in endemic and control villages. Copper content in cereals (p<0.05), pulses (p<0.01), and vegetables (p<0.01) in endemic villages was found significantly higher as compared to control villages. The overall prevalence of dental fluorosis in six endemic villages was 97.4% in boys and 96% in girls, which was significantly higher (p<0.01) than that of control villages, where it was 10.5% in boys and 8.3% in girls. The prevalence of dental fluorosis was positively correlated (r=0.125, p<0.01) to fluoride and negatively correlated to Ca and Cu content in drinking water in endemic villages.

Adolescent↗

PubMed2006

Prevalence of some bacteria yeasts and molds in meat foods in San Luis, Argentina.

In this work we evaluate the microbiological quality and the hygiene degree of meat foods consumed in the city of San Luis. A total of 515 meat food samples (315 from fresh sausages, 100 from hamburgers and 100 from ground beef) were processed, being the most of them non-industrial products. The microbiological quality was determined by counts of total mesophilic bacteria, coliforms, Escherichia coli, molds and yeasts, and Clostridium perfringens. The number of total mesophilic aerobes was within the 10(6) cfu/g limit set by the Argentinaan Alimentary Code (AAC). Two hundred seventy six samples exhibited E. coli levels between 10(1) and 10(3) cfu/g. The 58.26% of the samples with E. coli counts above > 10(1) cfu/g came from hamburgers and fresh sausages exceeding the AAC limits. Counts of molds and yeasts ranged between 10(3) and 10(6) cfu/g. From a total of 515 samples, 126 exhibited C. perfringens, out of which 80 (64.08%) gave counts > 10(2)/g, exceeding the limits set by the AAC. Out of these 80 samples, C. perfringens counts were above 10(5) cfu/g in 12 of them, and E. coli was also detected in 48 samples (38.10%). The samples with counts > 10(5) C. perfringens/g are potentially responsible for alimentary intoxication. The results obtained indicate the need to improve the processing and handling conditions of these products.

Argentina↗

PubMedDate not supplied

Atomic absorption spectrophotometric determination of chromium in foods.

A method is reported for determination of chromium in foodstuffs. Organic matter is digested with nitric acid, followed by oxidation to Cr(VI) and extraction with methyl isobutyl ketone (MIBK) after HCl addition. Chromium determinations are performed by flame absorption spectroscopy. Absence of interferences is verified and recovery tests are performed on food samples. Quantitation limit (3.8 ng/mL), accuracy (NBS Standard Reference Material 1,573 Tomato Leaves, 4,500 +/- 500 ng/g, found 3,860 +/- 409 ng/g), and precision (CV for vegetable matrix = 9.05%, CV for animal matrix = 14.95%) of the procedure are evaluated.

Chromium↗

PubMed1985

[Modified rapid method for the quantitative determination of S. aureus in food products and washings].

Suggested is the use of a modified rapid method for the quantitative determination of Staphylococcus aureus in food products and washings, worked out on the basis of the method described by Lachica [8]. In the modified method a yolk-salt agar is substituted for Baird-Parker's medium. Provided is inactivation of the thermolable nucleases at 65 degrees C for one hour and additional incubation at 37 degrees C for 2 hours following the overlaying of the agar with toluidineblue DN-ase agar. Comparative investigations on the quantitative determination of Staphylococcus aureus in experimentally and naturally contaminated food samples and washings showed that there were no essential differences between the microbial counts as established by the two methods. The modified method made it possible to shorten the investigation by 2 hours. It proved specific and readily applicable for rapid laboratory diagnostics.

Bacteriological Techniques↗

PubMed2002

Influence of composition of diluent on populations of yeasts and moulds recovered from raw fruits.

AIMS: The aims of this study were (i) to determine the retention of viability of mycoflora removed from raw fruits, and how this affected diluents used to prepare samples for enumeration of propagules, and (ii) to evaluate the performance of recovery media for supporting colony development. METHODS AND RESULTS: Yeasts and moulds removed from seven types of raw fruit were held in seven diluents for 1 h before plating on dichloran rose bengal chloramphenicol (DRBC) agar and plate count agar supplemented with chloramphenicol (100 micro g ml-1) (PCAC). Significant reductions (P=0.05) in populations of yeasts, moulds, and yeasts plus moulds occurred within the 1 h holding period, regardless of diluent composition. Overall, retention of viability was not influenced by diluent composition, and neither DRBC agar nor PCAC were superior in supporting colony development. CONCLUSIONS: The composition of diluents used to prepare food samples for mycological analysis has little affect on the number of yeasts and moulds recovered from seven types of naturally contaminated raw fruit. Both DRBC agar and PCAC are suitable as enumeration media. SIGNIFICANCE AND IMPACT OF THE STUDY: Diluents and media most often recommended for enumerating yeasts and moulds in foods are appropriate for raw fruits.

Colony Count, Microbial↗

PubMed1997

Urinary excretion of ethylenethiourea in five volunteers on a controlled diet (multicentric study).

Urinary excretion of ethylenethiourea (ETU) was monitored for 8 days in a group of five male non-smoker volunteers on a diet, the items of which were assayed for ETU and carbon sulphide. Urinary excretion of ETU reflected the consumption of wine, fruit and vegetables. Urinary ETU concentrations ranged from 0.6 to 6.7 micrograms/g creatinine. ETU concentrations in the food eaten by the volunteers were generally below the detection limit whereas in wine 8.8 micrograms/l ETU was detected. Evolution of carbon sulphide by food samples ranged from 0.03 to 0.17 mg/kg. Mean (+/- S.D.) daily intake of ETU in wine was 3.5 +/- 0.2% of the acceptable daily intake (ADI): 0.070 +/- 0.004 micrograms/kg body wt. During the 8 days of the study, an average of 48.3% of the ETU ingested in wine was excreted unmodified by the kidneys. Twenty-four hour urinary excretion of ETU was significantly correlated with daily intake of ETU (r = 0.768) and CS2 evolved by the daily food items (r = 0.414).

Adult↗

PubMedDate not supplied

Real-time polymerase chain reaction detection of cauliflower mosaic virus to complement the 35S screening assay for genetically modified organisms.

Labeling of genetically modified organisms (GMOs) is now in place in many countries, including the European Union, in order to guarantee the consumer's choice between GM and non-GM products. Screening of samples is performed by polymerase chain reaction (PCR) amplification of regulatory sequences frequently introduced into genetically modified plants. Primers for the 35S promoter from Cauliflower mosaic virus (CaMV) are those most frequently used. In virus-infected plants or in samples contaminated with plant material carrying the virus, false-positive results can consequently occur. A system for real-time PCR using a TaqMan minor groove binder probe was designed that allows recognition of virus coat protein in the sample, thus allowing differentiation between transgenic and virus-infected samples. We measured the efficiency of PCR amplification, limits of detection and quantification, range of linearity, and repeatability of the assay in order to assess the applicability of the assay for routine analysis. The specificity of the detection system was tested on various virus isolates and plant species. All 8 CaMV isolates were successfully amplified using the designed system. No cross-reactivity was detected with DNA from 3 isolates of the closely related Carnation etched ring virus. Primers do not amplify plant DNA from available genetically modified maize and soybean lines or from different species of Brassicaceae or Solanaceae that are natural hosts for CaMV. We evaluated the assay for different food matrixes by spiking CaMV DNA into DNA from food samples and have successfully amplified CaMV from all samples. The assay was tested on rapeseed samples from routine GMO testing that were positive in the 35S screening assay, and the presence of the virus was confirmed.

Base Sequence↗

PubMed1994

A 16S rDNA-based PCR method for rapid and specific detection of Clostridium perfringens in food.

A 16S rDNA-based polymerase chain reaction (PCR) method was developed for the rapid and specific detection of Clostridium perfringens in food. The PCR primers were designed by a GenBank computer search and they are complementary only with the 16S rRNA gene of C. perfringens by sequence alignment. The PCR product is a 279 BP DNA fragment. All C. perfringens strains tested were positive in the PCR assay and all other species tested were negative, including 11 other species of Clostridium and 38 species of other common bacteria. As few as two cells of C. perfringens in pure culture were detectable. High numbers of other bacterial species did not interfere with the detection of C. perfringens. The PCR amplification required only 30 min to complete. The method can be used for detection of C. perfringens in contaminated food. Samples from 100 g of chicken drumsticks which were inoculated with 20, 200 or 2000 cells of C. perfringens were subjected to the PCR assay and all produced positive results.

Animals↗

PubMed2000

Comparison of three enrichment media for the isolation of Campylobacter spp. from foods.

AIM: This study compared the performance of three Campylobacter enrichment broths: Bolton broth (BB), Campylobacter Enrichment broth (CEB) and Preston broth (PB). METHODS AND RESULTS: Pure cultures of target and competitor organisms, and naturally-contaminated food samples, were used to establish the performance of these media. In pure culture the PB supported the growth of the greatest number of strains of Campylobacter spp. but failed to inhibit some competitor organisms. The CEB showed the opposite result, inhibiting all 15 competitor organisms used but failing to support the growth of five Campylobacter strains. By comparison, BB showed the best compromise between inhibition of competitors and growth of Campylobacter. CONCLUSIONS: Plates inoculated with BB and CEB food enrichments resulted in more Campylobacter growth than those inoculated with PB, which supported significantly less typical growth (P < or = 0.001). The most common competitor organism isolated from PB was Escherichia coli, and Pseudomonas spp. were frequently isolated from BB and CEB. Both BB and CEB were better than PB for the isolation of Campylobacter from naturally-contaminated foods, although BB yielded more confirmed Campylobacter growth than CEB. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlighted differences in performance of media used to isolate Campylobacter spp. from foods.

Campylobacter↗

PubMedDate not supplied

Analytical challenges: bridging the gap from regulation to enforcement.

An overview is presented of the analytical steps that may be needed to determine the presence of genetically modified organisms (GMOs) or for analysis of GMO-derived produce. The analytical aspects necessary for compliance with labeling regulations are discussed along with bottlenecks that may develop when a plant product or a food sample is analyzed for conformity with current European Union GMO legislation. In addition to sampling and testing, other topics deal with complications that arise from biological and agricultural realities that may influence testing capabilities. The issues presented are intended to serve as elements to examine the different challenges that enforcement laboratories might face.

Crops, Agricultural↗

PubMed2004

Enhancement of data collection from Welsh 'shopping basket' ready-to-eat food surveillance programme.

The method of data collection from the Welsh 'shopping basket' ready-to-eat food sampling programme has recently been reviewed, with the principal aim of reducing the resources required for inputting and audit of data. The subsequent improvements made have been primarily software based and they have made data collection, audit and analysis significantly faster and more efficient.

Data Collection↗

PubMed1976

Selenium in foods: evaluation of atomic absorption spectrometric techniques involving hydrogen selenide generation and carbon furnace atomization.

The performance of hydrogen selenide generation- and carbon furnace atomization-atomic absorption spectrometry, with a semiautomated trace metal accessory and a carbon rod atomizer, respectively, was evaluated for the determination of selenium in foods. Samples were digested with nitric, perchloric, and sulfuric acids for both procedures. Hydrogen selenide was generated with stannous chloride/potassium iodide/zinc from 20 ml aliquots in a hydrochloric-sulfuric acid medium and directed into an argon-hydrogen-entrained air flame. Sample matrix interferences in the carbon furnace technique were minimized by isolating selenium by precipitation with ascorbic acid and redissolution in nitric-perchloric acid prior to taking 5 mul aliquots for estimation; precision was significantly improved by incorporating 5000 mug nickel/ml into analytical solutions. For the hydrogen selenide and carbon furnace techniques, respectively, the following data were obtained for untreated standard solutions: sensitivity, 0.13 and 10.0 ng/ml; absolute sensitivity, 2.6 and 0.05 ng; detection limit, 0.4 and 90 ng/ml; absolute detection limit, 7 and 0.45 ng. The detection limit and absolute detection limit for samples were 2.5 ng/ml and 50 ng, respectively, for the hydrogen selenide method, and 25 ng/ml and 0.13 ng, respectively, for the carbon furnace method. Taking into consideration these figures and the practical aspects of both methods, the overall performance of the hydrogen selenide method was superior.

Evaluation Studies as Topic↗

PubMedDate not supplied

Analysis of nitro-PAHs in food matrices by on-line reduction and high performance liquid chromatography.

Two different approaches to the analysis of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) in food samples are presented, based on liquid chromatography with fluorescence detection and gas chromatography with a mass selective detector as the alternative method. For the HPLC analysis the nitro-PAHs at trace level concentrations are efficiently reduced to primary aromatic amines on a catalyst column packed with 5 microns alumina coated with platinum and rhodium. The particulate extraction/fractionation procedure is discussed and the results of both methods are compared. The concentrations of seven nitro-PAHs in grilled and smoked food are presented.

Animals↗

PubMed1996

An alanine racemase gene as a new index for detecting Escherichia coli in foods.

A gene of alanine racemase, a typical prokaryotic enzyme, was evaluated as a new index for detecting Escherichia coli in foods. An alanine racemase gene fragment containing a non-conserved sequence of the gene was amplified from genomic DNA of E. coli by a polymerase chain reaction, and then labeled with digoxigenin as a probe for detecting E. coli. Food samples and bacteria were each treated as at 25 degrees C for 10 min in 0.1N NaOH containing 0.5% SDS, before being directly spotted on to nylon membranes for DNA hybridization. The probe was specific for E. coli; all 48 strains of E. coli examined, including such pathogenic strains as E. coli O157:H7, showed positive signals, whereas all 59 strains of non-E. coli species, except for one strain (Shigella sonnei), did not show a signal. Various foods inoculated with E. coli K-12 showed positive signals whereas no uninoculated foods showed any signal. Quantification of E. coli cells in the death phase by the hybridization method showed good correlation with that by the plate culture method. The alanine racemase gene could prove useful as an index for detecting E. coli in foods.

Alanine Racemase↗

PubMed1985

Determination of total iron in foods by isotope dilution fast atom bombardment mass spectrometry.

A method employing isotope dilution fast atom bombardment mass spectrometry has been developed for the quantitative determination of iron in foods. Samples were spiked with an enriched source of 54Fe, digested with concentrated HNO3/H2SO4 and the iron extracted from 6 M HCl into diethyl ether. Bracketing procedures gave precisions ranging from 1.30-4.49% relative standard deviation (RSD) for isotope ratio measurements and 1.26-6.44% RSD for iron measurements.

Food Analysis↗

PubMed1999

2-Alkylcyclobutanones as markers for irradiated foodstuffs. III. Improvement of the field of application on the EN 1785 method by using silver ion chromatography.

The inclusion of a purification step by silver ion chromatography in the EN 1785 analytical protocol for 2-alkylcyclobutanones (validated by the European Committee for Standardization for the detection of ionizing radiation treatment) has considerably improved the quality of the chromatograms obtained, allowing the detection of food samples irradiated at very low doses (0.1 kGy) or irradiated ingredients included in low proportions in non irradiated foodstuffs. This analytical modification of the protocol EN 1785 ought thus to permit a very considerable extension of its current field of application.

Butanones↗

PubMed2006

Effectiveness of ionizing radiation in reducing furan and acrylamide levels in foods.

Furan and acrylamide are two possible carcinogens commonly found in many thermally processed foods. The possibility of using ionizing radiation to reduce the levels of thermally induced furan and acrylamide in water and selected foods was investigated. Aqueous furan solutions, and foods (frankfurters, sausages, infant sweet potatoes) that contained furan were irradiated to various doses of gamma-rays. Water and oil spiked with acrylamide and potato chips (a known acrylamide-containing food) were also irradiated. In addition, possible irradiation-induced formation of acrylamide in glucose and asparagine solutions was analyzed. Results showed that irradiation at 1.0 kGy destroyed almost all furan in water. In frankfurters, sausages, and infant sweet potatoes, the rate of irradiation-induced destruction of furan was much lower than the rate in water, although significant reductions in furan levels were observed in all foods. Irradiation at 2.5-3.5 kGy, doses that can inactivate 5-log of most common pathogens, reduced furan levels in the food samples by 25-40%. Similarly to furan, acrylamide in water was also sensitive to irradiation. After 1.5 kGy of irradiation, most of the acrylamide was degraded. Irradiation, however, had a very limited effect on acrylamide levels in oil and in potato chips, even at a dose of 10 kGy. No detectable acrylamide was formed in the mixture of asparagine and glucose upon irradiation. These results suggest that a low dose of irradiation easily destroys furan and acrylamide in water. In real foods, however, the reduction of furan was less effective than in water, whereas the reduction in acrylamide was minimal.

Acrylamide↗

PubMed2004

Updated perspectives on emerging vibrios associated with human infections.

This review describes the ecological, clinical and epidemiological features of emerging vibrios and discusses what laboratory methods are being used for the detection of pathogenic vibrios in clinical, environmental and food samples. After selecting articles illustrative of the current scientific research on pathogenic vibrios, the review focuses on the need for better insight into the risk factors of emerging infections to establish adequate prevention procedures.

Bacteremia↗