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PubMed2003

Estimation of inorganic food additive (nitrite, nitrate and sulfur dioxide), antioxidant (BHA and BHT), processing agent (propylene glycol) and sweetener (sodium saccharin) concentrations in foods and their daily intake based on official inspection results in Japan in fiscal year 1998.

The mean concentration and daily intake of inorganic food additives (nitrite, nitrate, and sulfur dioxide), antioxidants (BHA and BHT), a processing agent (propylene glycol), and a sweetener (sodium saccharin) were estimated based on the results of an analysis of 34,489 food samples obtained in official inspections by 106 local governments in Japan in fiscal year 1998. The ratios of mean concentrations of these seven food additives to each allowable limit were 20.0%, 53.9%, 15.5%, 6.2%, 0.4%, 18.5%, and 5.7%, respectively. The daily intakes of these food additives estimated from their concentrations in foods and the daily consumption of foods were 0.205, 0.532, 4.31, 0.119, 0.109, 77.5, and 7.27 mg per person, respectively. These amounts were 6.8%, 0.3%, 12.3%, 0.5%, 0.7%, 6.2%, and 2.6% of the acceptable daily intake (ADI), respectively, when body weight was assumed to be 50 kg. No remarkable differences in the daily intakes of these seven food additives or the ratios to the ADI were observed compared with the results based on the official inspections in fiscal years 1994 and 1996.

Antioxidants↗

PubMed1991

[A review of the studies on fungi and mycotoxins in foodstuffs in Beijing during 1976-1986].

Fungi and mycotoxins contaminating foods in Beijing during 1976-1986 were studied. A total of more than 5,000 food samples classified into 104 kinds of 16 types were examined of analysed. The results showed that the natural occurrence of Aflatoxin B1 in foods in Beijing was not serious, but from the results of analysis 59 cases of food poisoning and food seriously contaminated with moulds, the hazards of fungal contamination of food should receive serious consideration. In order to improve food hygiene and facilitate supervision the author suggested that a mycological standard should be established for marketing foods in China, such as grain, and beverage which are highly susceptible to fungal contamination.

Aflatoxin B1↗

PubMed1998

Feline calicivirus as a model system for heat inactivation studies of small round structured viruses in shellfish.

Commercial heat treatment procedures for molluscan shellfish are based on data obtained for the inactivation of hepatitis A virus (HAV) in cockles. However, the most frequently reported illness associated with consumption of bivalve molluscs is gastroenteritis caused by small round structured viruses (SRSVs) of the Norwalk group. Conditions for inactivation of SRSVs are unknown. In this study a feline calicivirus was used as a model for the SRSV group and conditions for its heat inactivation determined. Experiments showed that feline calicivirus is more readily inactivated in shellfish than HAV, and confirmed that current heating recommendations to the UK shellfish industry are adequate. A reverse transcription polymerase chain reaction (RT-PCR) assay for the detection of calicivirus in shellfish was developed and results compared with isolation in cell culture. The RT-PCR detected virus in some samples that failed to yield virus on culture. This has important implications if molecular virology techniques are to be used in the design and monitoring of shellfish treatment procedures and for routine testing of food samples.

Animals↗

PubMed2006

Evaluation of immunomagnetic separation-polymerase chain reaction in direct detection of Brucella abortus and Brucella melitensis from cheese samples.

The current study was carried out to assess the use of immunomagnetic separation-polymerase chain reaction (IMS-PCR) in direct detection of Brucella abortus and B. melitensis from soft cheese and to examine a relatively small number of field samples for the presence of these species. Two methodologies, one with IMS and the other without IMS, were employed for recovery of the Brucella species from cheese samples. IMS in conjunction with the PCR assay was determined to detect as low as 3x10(2) bacteria/mL, while the limit of detection with the other extraction procedure was 3x10(3) bacteria/mL. In the analysis of 40 cheese samples collected from various markets, only B. abortus was detected by PCR using both DNA extraction procedures in two (5%) samples. No positive results were obtained by culture and B. melitensis was not found in any cheese samples examined. The results suggest that this technique is promising owing to its pace and high sensitivity and should aid in direct detection of Brucella species from complex food samples.

Brucella abortus↗

PubMed2000

Biotechnical use of polymerase chain reaction for microbiological analysis of biological samples.

Since its introduction in the mid-80s, polymerase chain reaction (PCR) technology has been recognised as a rapid, sensitive and specific molecular diagnostic tool for the analysis of micro-organisms in clinical, environmental and food samples. Although this technique can be extremely effective with pure solutions of nucleic acids, it's sensitivity may be reduced dramatically when applied directly to biological samples. This review describes PCR technology as a microbial detection method, PCR inhibitors in biological samples and various sample preparation techniques that can be used to facilitate PCR detection, by either separating the micro-organisms from PCR inhibitors and/or by concentrating the micro-organisms to detectable concentrations. Parts of this review are updated and based on a doctoral thesis by Lantz [1] and on a review discussing methods to overcome PCR inhibition in foods [2].

Animals↗

PubMed2000

Comparison between HPLC and MALDI-TOF MS analysis of anthocyanins in highbush blueberries.

High-performance liquid chromatography (HPLC) has been widely used as a reliable technique to quantify anthocyanins in food samples. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a new technique that is having a great impact on food analysis. This study is the first to compare HPLC and MALDI-TOF MS quantifications of anthocyanins. The analyses were carried out for highbush blueberries at different stages of anthocyanin formation. In general, both techniques provided comparable quantitative anthocyanin profiles for the samples. HPLC could distinguish anthocyanin isomers, whereas MALDI-TOF MS proved to be more rapid in the accurate identification and quantification of anthocyanins with different masses. A single MALDI-TOF MS run took just 4 min. MALDI-TOF MS analysis can serve as a rapid alternative to HPLC for the analysis of anthocyanins in fruits.

Anthocyanins↗

PubMed1992

A study of the incidence of different fluorescent Pseudomonas species and biovars in the microflora of fresh and spoiled meat and fish, raw milk, cheese, soil and water.

Of 182 various foodstuffs and environmental samples examined, 86% had microflora containing fluorescent Pseudomonas in differing proportions. A computer-aided technique was used to identify most of the 445 fluorescent strains. Pseudomonas fluorescens biovar V-1 was most frequently isolated (24%); it either predominated or was present in all types of samples. Other strains, belonging to the other subgroups of biovar V (V-2, V-4, V-5, V-6 and V-7), together represented 14.3%. We also identified Ps. fluorescens biovars I-1 and I-2 (13.9%), II-1 and II-3 (3.6%), III-1 and III-2 (8.7%), IV-2 (0.7%); Ps. putida A and B (11%); Ps. lundensis (10.3%); group B3 (2%) and Ps. aeruginosa (0.7%). Unidentified strains accounted for 10.6% of the flora, many resembling Ps. fluorescens biovar V. Although the presence of Ps. fluorescens V-1 was often marked, other taxa predominated or were present in large quantities in some particular samples, such as Ps. fluorescens I-1 in raw milk and cheese, Ps. lundensis in spoiled meat and Ps. fluorescens III-1 in spoiled fish. Pseudomonas putida A and B were evident in environmental rather than in food samples.

Animals↗

PubMed1992

Use of the polymerase chain reaction for specific detection of type A, D and E enterotoxigenic Staphylococcus aureus in foods.

By comparison with the DNA sequences coding for Staphylococcus aureus enterotoxins (ents) A, B, C, D and E, oligonucleotides unique to the entA, entD and entE genes were synthesized and used as polymerase-chain-reaction (PCR) primers for the specific detection of type A, D or E enterotoxigenic S. aureus. The relative molecular weights of the PCR products amplified with these primers were 210, 333 and 456 bp, respectively. Despite the high relatedness among these S. aureus enterotoxin genes, each primer pair allows specific detection with total discrimination from other types of enterotoxigenic S. aureus. DNA from non-enterotoxigenic S. aureus or from non-S. aureus would not interfere with the PCR results either. Primers designed for entE detection allow the discrimination of entE strains that when assayed by a serological method might be classified as entA-producing strains. Study of the detection sensitivity showed that by using these primers, DNA from 10(0) cells of enterotoxigenic S. aureus could be detected unambiguously. When these oligonucleotide primers were used for the detection of S. aureus in foods, 10(0)-10(1) cells per gram of food could be detected and the naturally contaminating microflora in the food sample did not interfere with the detection.

Base Sequence↗

PubMed1984

Selenium intake of infants and young children, healthy children and dietetically treated patients with phenylketonuria.

In 20 healthy infants and children, 5-20 months old, the Se intake was estimated by analysing food samples by instrumental neutron activation analysis. The intake was calculated by weighing the portions offered and actually consumed. The median Se content of the food amounted to 27 ng/g wet weight (gww) and median daily Se intake to 33.5 micrograms. The Se intake was not equally distributed over the day. About 50% of the daily Se intake was derived from the supper. The main Se sources (41%) for young children were cereal paps. Commercially available meals (30 ng/g) contained less Se than home-made ones (50 ng/g). In nine dietetically treated patients with phenylketonuria the median Se intake amounted only to 6.9 micrograms/day corresponding to a mean Se content of the diet of 7.9 ng/g. The main Se source in the diet was vegetables (36.3%) and 20% derived from their protein supplements. The Se intake of young children, healthy or dietetically treated, cannot be calculated accurately from tables but must be estimated by measuring the Se content of the local food because cereals and vegetables--the main Se sources--exhibit great regional variations.

Age Factors↗

PubMed1997

A universal protocol for PCR detection of 13 species of foodborne pathogens in foods.

A universal protocol for PCR detection of 13 species of foodborne pathogens in foods was developed. The protocol used a universal culture medium and the same PCR conditions with 13 sets of specific primers. The 13 species of foodborne pathogens examined were Escherichia coli, E. coli-ETEC, E. coli-O157:H7, Shigella spp., Salmonella spp., Yersinia enterocolitica, Y. pseudotuberculosis, Vibrio cholerae, V. parahaemolyticus, V. vulnificus, Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus. No interference was observed using the PCR assay when food sample was artificially inoculated with each individual bacterial species. Twelve different seafood samples and two soft cheese samples without artificial inoculation were examined by this protocol. Vibrio vulnificus, Salmonella spp., E. coli, Listeria monocytogenes and Bacillus cereus were detected in some foods. Internal probe hybridization and nested PCR procedures were used to confirm the above findings.

Bacteria↗

PubMed2001

Emergence of Salmonella enteritidis phage type 4 in the Caribbean: case-control study in Trinidad and Tobago, West Indies.

A prospective case-control study involving 46 case patients and 92 age- and neighborhood-matched control subjects was conducted in Trinidad and Tobago (T&T) between March 1998 and May 1999 to determine the etiology, sources, and risk factors for Salmonella enteritidis (SE) infection. SE infection in T&T was found to be associated with the consumption of shell eggs, and in particular raw or undercooked eggs. SE isolates from 30 (88%) of 34 patients and from 9 implicated egg or egg-containing food samples were phage type 4. Homemade eggnog and ice cream, cake batter, and egg-containing beverages were the main raw egg-containing foods, reflecting the cultural practices of the people of T&T. Public health education on the risks of eating raw or undercooked eggs, thorough cooking of all egg dishes, and refrigeration of shell eggs and egg dishes; studies tracing infected eggs to their sources; and testing of flocks of layer chickens for SE are needed to reduce the incidence of this infection.

Adolescent↗

PubMed2002

Rapid and quantitative detection of the microbial spoilage of meat by fourier transform infrared spectroscopy and machine learning.

Fourier transform infrared (FT-IR) spectroscopy is a rapid, noninvasive technique with considerable potential for application in the food and related industries. We show here that this technique can be used directly on the surface of food to produce biochemically interpretable "fingerprints." Spoilage in meat is the result of decomposition and the formation of metabolites caused by the growth and enzymatic activity of microorganisms. FT-IR was exploited to measure biochemical changes within the meat substrate, enhancing and accelerating the detection of microbial spoilage. Chicken breasts were purchased from a national retailer, comminuted for 10 s, and left to spoil at room temperature for 24 h. Every hour, FT-IR measurements were taken directly from the meat surface using attenuated total reflectance, and the total viable counts were obtained by classical plating methods. Quantitative interpretation of FT-IR spectra was possible using partial least-squares regression and allowed accurate estimates of bacterial loads to be calculated directly from the meat surface in 60 s. Genetic programming was used to derive rules showing that at levels of 10(7) bacteria.g(-1) the main biochemical indicator of spoilage was the onset of proteolysis. Thus, using FT-IR we were able to acquire a metabolic snapshot and quantify, noninvasively, the microbial loads of food samples accurately and rapidly in 60 s, directly from the sample surface. We believe this approach will aid in the Hazard Analysis Critical Control Point process for the assessment of the microbiological safety of food at the production, processing, manufacturing, packaging, and storage levels.

Artificial Intelligence↗

PubMed2005

Intakes of calcium and other nutrients related to bone health in Japanese female college students: a study using the duplicate portion sampling method.

The purposes of this study were to determine intakes of nutrients related to bone health, such as calcium (Ca), phosphorus (P), sodium (Na), potassium (K), and protein, in Japanese female college students, using the duplicate portion sampling method, and to identify possible lifestyle factors explaining their calcium intakes. Subjects were 106 Japanese female college students aged 19-23 years. All foods in the duplicate portions, as eaten by the subjects during a three-weekday period, were collected. The minerals and protein in the food samples were analyzed. Life-style information was obtained by interview. Levels of cognitive eating restraint (CER) were assessed by the Three-Factor Eating Inventory. Average intakes of dietary Ca, P, Na, K, and protein were 380 (SD 209) mg/day, 649 (SD 212) mg/day, 2,535 (SD 847) mg/day, 1,108 (SD 429) mg/day, and 41.7 (SD 12.6) g/day, respectively. Ca intake was significantly associated with the frequency of milk intake (R2 = 0.278, p < 0.001), intake of other dairy products (R2 = 0.338, p < 0.001), and meal skipping (R2 = 0.161, p < 0.001), but not with CER score (p = 0.378). Female college students are at high risk for poor Ca nutrition. Low intake of nutrients relevant to bone health is considered to adversely affect bone metabolism in young women.

Adult↗

PubMed2006

Flow injection spectrophotometric determination of bromoxynil herbicide by diazotization method.

A flow injection spectrophotometric method is proposed for the determination of bromoxynil herbicide. Bromoxynil was hydrolyzed with HCl and the resulting product, 3,5-dibromo-4-hydroxyaniline, was diazotized with nitrite and coupled with aniline. The absorbance of the azo dye was measured at 500 nm. The conditions were optimized for diazotization using FIA. The range of linearity was found to be 0.01 to 5 ppm with a molar absorptivity of 1.27 x 10(5) L mol(-1) cm(-1). The % recovery for the determination of bromoxynil was found to be 91%. The sampling frequency was 80 samples per hour for FIA. The method is simple, fast, and has been successfully applied to the determination of bromoxynil in commercial formulations and food samples.

Azo Compounds↗

PubMed1999

Microbiological quality of prepared foods from selected kitchen outlets in Lahore, Pakistan.

Following UK PHLS guidelines, a total of 166 food samples from a variety of different kitchen outlets were examined for microbiological quality. Over 60% of the samples had satisfactory aerobic plate counts, and only 10% (8.5-18.7% of the samples, depending on the nature of the product) were classified as unsatisfactory. Almost 85% of samples presented with low coliform counts, and 6.6% were found to have unsatisfactory or unacceptable levels. Salmonella was found in only one sample, which had been purchased from a street trader.

Developing Countries↗

PubMed1985

Trace determination and isotopic analysis of the elements in life sciences by mass spectrometry.

The main ionization methods in a mass spectrometer for isotope ratio determinations of the elements are discussed in this review. These methods are thermal ionization, spark source, electron impact, inductively coupled plasma and field desorption. As concerns thermal ionization, electron impact and field desorption, a survey of the possibilities of isotope analyses in the periodic table of the elements is given. Besides kinetic studies, trace element determination by isotope dilution technique is the main application for isotope ratio measurements of the elements. The definitive method, isotope dilution mass spectrometry, is discussed as a potential tool for achieving accurate and precise trace analyses. Using field desorption mass spectrometry, one example of calcium kinetics in man and one example of thallium trace determination in an animal tissue are given. Other metal trace analyses with the isotope dilution technique are presented for biological and medical samples using positive thermal ionization mass spectrometry. Negative thermal ions are formed for the mass spectrometric analysis of non-metals and non-metal compounds in food samples, e.g. for iodine and nitrate in milk powder. Preliminary results with the isotope dilution technique are presented for a new quadrupole thermal ionization mass spectrometer which is a low-cost instrument and can be easily handled.

Animals↗

PubMed2004

Evaluation of a 5'-nuclease (TaqMan) assay with the thin agar layer oxyrase method for the detection of Yersinia enterocolitica in ground pork samples.

A 5'-nuclease (TaqMan) assay was evaluated for its capability to recover and detect stressed Yersinia enterocolitica. Sensitivity studies of a 5'-nuclease assay for detecting Y. enterocolitica 0:8 in a pure culture system and spiked ground pork samples demonstrated that the assay has reliable sensitivity with a detection limit of 3 to 4 log CFU/ml or CFU/g. The PCR 5'-nuclease (TaqMan) assay was evaluated with the Thin Agar Layer Oxyrase method (TALO, overlaying 14 ml of Trypticase soy agar with a 1:30 dilution of "Oxyrase for Agar" onto a prepoured pathogen-specific, selective medium), and it was compared against the selective medium cefsulodin-irgasan-novobiocin (CIN) for recovering and detecting Y. enterocolitica from inoculated nonfrozen and frozen (-15 degrees C, 2 days) ground pork samples. The TALO method showed more sensitivity (detection limit, 2 log CFU/ml), and it has greater recovery capability (0.5 to 1 log CFU/ml) than CIN (P < 0.05). The 5'-nuclease assay provided rapid detection processing (5 versus 24 h after an 18-h enrichment). The sensitivity per PCR was calculated to as low as 0 to 1 log CFU per PCR reaction; however, in the method's current developmental stage, target pathogens should be enriched to 3 to 4 log CFU/ml or CFU/g to show consistent results. In a survey of 100 ground pork samples using TALO, CIN, and PCR methods, no Y. enterocolitica was recovered. A combined cultivation and an automated PCR TaqMan could be used as a presumptive screening test for detecting Y. enterocolitica in food samples.

Animals↗

PubMed2004

Highly sensitive analysis of multiple pesticides in foods combining solid-phase microextraction, capillary electrophoresis-mass spectrometry, and chemometrics.

A highly sensitive procedure to detect multiple pesticides at trace levels in foods is presented. Initially a comparative study between capillary electrophoresis (CE)-UV and CE-mass spectrometry (MS) is carried out analyzing five pesticides not studied up to now (pyrimethanil, pyrifenox, cyprodinil, cyromazine, and pirimicarb). The comparison between CE-UV and CE-MS is established in terms of separation efficiency, speed of analysis, reproducibility, and sensitivity. A good separation of these compounds is achieved by both techniques using a volatile aqueous buffer containing 0.3 M ammonium acetate/acetic acid at pH 4. Time analysis reproducibility is studied for the same day (n = 5) and three different days (n = 15), showing no significant differences between CE-UV and CE-MS. The study on peak areas reproducibility shows a slightly worse reproducibility for CE-MS compared with CE-UV. The best limit of detection (LOD) that can be achieved for these pesticides using CE-UV was 0.6 microg/mL. CE-MS provides LODs one order of magnitude better than CE-UV. Chemometrics are used to optimize the multiple parameters that play a role in solid-phase microextraction (SPME) and CE-MS analysis (e.g., extraction and desorption times, nebulizer pressure, dry gas flow, dry gas temperature, percentage of organic solvent and acid in the sheath liquid, etc.). The combined use of chemometrics and SPME-CE-MS clearly improves the LODs that can be achieved allowing the detection of pesticides at concentrations down to 15 ng/mL. The usefulness of this approach is demonstrated detecting multiple pesticides in different food samples as grapes and orange juice in a single run. The concentrations detected are below the maximum residue limits (MRLs) permitted for these pesticides in foods corroborating the value of our approach. This work demonstrates, to our knowledge for the first time, the good possibilities of the combined use of SPME-CE-MS and chemometrics.

Absorption↗