M1 Content Research Articles

Head Space Sensor Array for the Detection of Aflatoxin M1 in Raw Ewe's Milk

A novel screening method was developed for simple and rapid detection of aflatoxin M1 contamination in raw ewe's milk samples without the need for sample pretreatment. The method was based on the use of a commercial head space sensor array system constituted by 12 metal oxide semiconductor sensors, 10 metal oxide semiconductor field-effect transistor sensors, and a pattern recognition software. Twenty-four raw milk samples collected from two different groups of ewes fed with a formulated feed that contained increasing amounts of aflatoxin B1 and six noncontaminated ewe's milk samples were analyzed. The results obtained by using the head space sensor array, processed by statistical methods, made it possible to group the samples according to the presence or the absence of aflatoxin M1. Sample classification was in complete agreement with the aflatoxin M1 content measured by an enzyme-linked immunosorbent assay procedure. This is the first report, to our knowledge, of detection of aflatoxin M1 in ewe's milk by a multisensor array.

Forecasting Real GDP: What Role for Narrow Money?

This paper analyses the information content of M1 for euro area real GDP since the beginning of the 1980s and reviews theoretical arguments on why real narrow money should help predict real GDP. We find that, unlike in the U.S., in the euro area, M1 has better and more robust forecasting properties for real GDP than yield spreads. This property persists when one controls for a number of other influences. We also evaluate the out-of-sample forecasting performance of different classes of VAR models comprising real M1, GDP and other indicators, using as benchmark a simple univariate model. As a result, only VARs in first differences are able to outperform the benchmark.

The real-time predictive content of money for output

Data on monetary aggregates are subject to periodic redefinitions, presumably in part to improve their link to measures of output. Money data are also revised on a regular basis. Taking these data imperfections into account, we reassess the evidence on the marginal predictive content of M1 and M2 for real and nominal output. In particular, first by using the latest version of the data that is available, and then using sequences of historical time series that would have been available to forecasters in real-time, we are able to provide a comprehensive assessment of whether money is useful for predicting output. We conclude that the generally significant marginal predictive content of M1 or M2 for output that is found using a recently revised data set is not duplicated in a real-time setting, although M2 is shown to remain useful when 1-year ahead forecasts are constructed using fitted vector autoregressive models.

The Real-time Predictive Content of Money for Output

Data on monetary aggregates are subject to periodic redefinitions, presumably in part to improve their link to measures of output. Money data are also revised on a regular basis. Taking these data imperfections into account, we reassess the evidence on the marginal predictive content of M1 and m2 for real and nominal output. In particular, by first using the latest version of the data that is available, and then using sequences of historical time series that would have been available to forecasters in real-time, we are able to provide a comprehensive assessment of whether money is useful for predicting output. We conclude that the generally significant marginal predictive content of M1 and m2 for output that is found using a recently revised data set is not duplicated in a real-time setting, although M2 is shown to remain useful when 1-year ahead forecasts are constructed using fitted vector autoregressive models.

Incidence of Aflatoxin M1 in Thai Milk Products

Two hundred seventy samples of raw milk and off-the-shelf milk products were examined for aflatoxin M1 content using a radioimmunoassay. Aflatoxin M1 was found in the majority of milk samples except 1 sample of raw milk and 11 samples of imported powdered milk. All cases of aflatoxin M1 content greater than 0.5 ppb were found in 18% (48) of the samples including raw milk (17/67), pasteurized milk (20/63), ultra high temperature milk (7/60), sterilized milk (3/60), and pelleted milk (1/7). All powdered milk samples were negative for aflatoxin M1 except two samples with less than 0.1 ppb. The positive aflatoxin M1 test results for five of the raw milk samples were confirmed by HPLC.

Application of Immunoaffinity Column Cleanup to Aflatoxin M1 Determination and Survey in Cheese

Milk products such as cheeses may be contaminated by aflatoxin M1 when manufactured with milk from dairy cattle that have consumed aflatoxin B1-contaminated feeds. The usefulness of immunoaffinity columns to determine aflatoxin M1 content in many kinds of cheeses with very good recoveries is demonstrated. The analysis of aflatoxin M1 in a 1990 to 1995 limited survey in France shows that the occurrence of this mycotoxin in cheeses is rather infrequent. With the exception of samples from 1989 to 1990 when aflatoxin B1-contaminated maize meals were incidentally imported to supplement dairy cattle feed, very few samples were found with above 0.200 μg of aflatoxin M1 per kg of cheese, the maximum acceptable level.

Ethanol disordering of G M1-enriched Short-Sleep synaptosomal plasma membranes

The Long-Sleep (LS) and Short-Sleep (SS) mouse synaptosomal plasma membranes differ in ethanol sensitivity at superficial membrane regions, which corresponds with the behavioral response of the mice to ethanol hypnosis. The only significant difference between these synaptosomal plasma membranes is the synaptosomal monosialoganglioside (G M1) content, LS > SS. Here, G M1 was examined as a parameter for increasing membrane sensitivity to ethanol effects in the ethanol-resistant SS membranes. Synaptosomal plasma membranes from SS mice were allowed to incorporate exogenous G M1. Membrane order was then studied at the surface, intermediate, and interior regions of the membranes by delayed Fourier transform proton NMR in the presence and absence of perdeuterated ethanol. Differences in membrane order were observed in all three membrane regions with increasing perdeuterated ethanol concentrations depending on the synaptosomal G M1 content.

Studies on the synthesis and properties of copolyesterimide

AbstractA series of copolyesterimides was prepared from bisphenol A, diacid (terephthalic acid [TPA] or isophthalic acid [IPA]), and 4‐carboxy‐N‐(p or m‐hydroxyphenyl) phthalimide (M1 or M2) in the presence of diphenyl chlorophosphate (DPCP) and pyridine as the direct condensation agent. Copolyesterimides derived from M1 showed poorer solubility than that of M2 during polymerization; a lower M1 content should be employed to prevent precipitation of the resulting polymers. The inherent viscosities of copolyesterimides were in the range of 0.33–0.56 dL/g. Some of these copolyesterimides were completely soluble in N‐methyl‐2‐pyrrolidone (NMP), N, N‐dimethylacetamide (DMAC), dimethylformamide (DMF), and m‐cresol. The thermal properties of copolyesterimides were examined by DSC and TGA. These copolyesterimides had glass transition temperatures in the range of 173–220°C and a 5% weight loss was observed in the range of 435–482°C. © 1994 John Wiley & Sons, Inc.

A small percentage of influenza virus M1 protein contains zinc but zinc does not influence in vitro M1-RNA interaction

A peptide containing the CCHH motif, the putative zinc-binding sequence of influenza virus M1 protein, was found to bind zinc in a one-to-one complex with the characteristics of a typical zinc-binding peptide. Intact influenza virus also contained zinc and we show that this zinc is bound to the M1 protein in the virus. However, only a small proportion of M1 contained zinc: 4% in virus and 6 to 9% in isolated protein. One strain, B/Yamagata/16/88, consistently contained more zinc: 15 to 20% both in virus and in isolated protein. We also determined the RNA binding and transcription inhibition activities of various M1 proteins and found that the zinc content of M1 had no influence on either activity. We suggest that the zinc in M1 has a structural role in the virion other than nucleic acid binding.

Development of Milk Powder Reference Materials Certified for Aflatoxin Mt Content (Part II): Certification of Milk Powder RM 283

The development of a full cream milk powder reference material, certified for its aflatoxin M1 content (target concentration: 0.1 microgram/kg), is described. The material (RM 283) was prepared and certified within the Reference Material Programme of the Community Bureau of Reference, along with other members of a series of milk powder reference materials. Homogeneity, evaluated by determining the aflatoxin M1 content of 30 units, was found to be acceptable (coefficient of variation of analysis results: 9.1%); stability has been demonstrated in a long-term study. The certification exercise involved 7 laboratories. Calibration, control of recoveries, blank values, and independence of the replicate measurements were emphasized. All sets of results of the certification exercise were accepted for statistical evaluation. A certified value for the aflatoxin M1 content: 0.09(+0.04)(-0.02) micrograms/kg was derived. The certification of RM 283 completes the series of 4 milk powder reference materials having certified aflatoxin M1 contents.

Aflatoxin M1 in whole milk-powder reference materials.

The development of three full cream milk powder reference materials, certified for their aflatoxin M1 content, is briefly described. The materials were prepared and certified within the Reference Material Programme of the Community Bureau of Reference. The three reference materials RM's 282, 284 and 285 contain aflatoxin M1 at concentrations of: less than 0.05 microgram/kg, 0.31 +/- 0.06 microgram/kg, and 0.76 +/- 0.05 microgram/kg.

Presence of aflatoxin M1 in commercial ultra-high-temperature-treated milk.

Forty-seven samples of commercial ultra-high-temperature-treated milk from a dairy facility in the northwest part of Spain were analyzed for the presence of aflatoxin M1. A total of 14 samples (29.8%) were positive for aflatoxin M1 (4 in May, 3 in November, 3 in December, 1 in January, 1 in April, 1 in July, and 1 in August), 29 (61.7%) were negative, and 4 (8.5%) were doubtful, i.e., they showed trace quantities of aflatoxin M1. The range of aflatoxin M1 content was 0.02 to 0.1 ng/ml.

Development of mycotoxin reference materials

The analytical difficulties in mycotoxin determination have given rise to the development of mycotoxin reference materials by the European Community Bureau of Reference (BCR) in cooperation with several European Laboratories, among them the National Institute of Public Health and Environmental Protection. The first project undertaken concerned four milk powders certified for their aflatoxin M1 content (concentrations 0, 0.1, 0.3 and 0.8 μg/ kg). Projects that are well-advanced include two peanut meals (aflatoxin B1 contents 0 and ca. 200 μg/kg) and two compounded animal feedingstuffs (aflatoxin B1 contents 0 and 10 μg/kg). Mycotoxin reference materials are also under development for zearalenone in wheat and maize, and for ochratoxin A in wheat.

Development of Milk Powder Reference Materials Certified for Aflatoxin M1 Content (Part I)

The development of 3 full-cream milk powder reference materials, certified for their aflatoxin M1 content, is described. The materials were prepared and certified within the Reference Material Programme of the Community Bureau of Reference (BCR). The 3 reference materials, RMs 282, 284, and 285, contain aflatoxin M1 at concentrations of less than 0.05, 0.31 +/- 0.06, and 0.76 +/- 0.05 micrograms/kg, respectively. The preparation, testing for homogeneity, stability of the reference materials, and the certification exercise, which was preceded by 2 intercomparisons of methods, are discussed. Particular emphasis was placed on the independence of the measurements in the certification exercise and the control of errors associated with extraction efficiency and the aflatoxin M1 calibrant. Finally, some guidance is given on avoiding the principal sources of errors in the determination of aflatoxin M1. Details concerning the supply of the reference materials will be provided by BCR on request.

Implications to garnet-clinopyroxene geothermometry of non-ideal solid solution in jadeitic pyroxenes

Garnet-clinopyroxene geothermometry has been applied to numerous rock types from the blueschist and eclogite terrain of the Sesia zone in the Western Alps. Discrepancies in apparent temperatures of up to 600° C have been found suggesting substantial deviation from ideal behaviour of the garnet-clinopyroxene equilibria in certain assemblages. Assemblages containing jadeitic pyroxenes rather than omphacitic or diopsidic pyroxenes yield very low KD (2.0) values and correspondingly high apparent temperatures (> 1,000° C). The garnets coexisting with high-Na pyroxenes have compositions similar to those coexisting with omphacitic pyroxenes. Departure from ideal behaviour of these garnets is likely to be minor and is accomodated in the formulation of the geothermometer. Numerous examples of coexisting garnet-clinopyroxene pairs indicate that there is no obvious relationship of KD with jadeite content in pyroxenes with jadeite content less than ∼70%, but at higher values, KD varies inversely with the jadeite content. The dependence of KD upon the jadeite content in the high-Na pyroxenes is believed to be due to the preference of M2 sites for Fe2+ in the enstatite-jadeite substitution (Fe2+MgNa−1Al−1). This substitution is usually very limited and has no demonstrable effect upon X Fe Cpx when the M1 (Fe2++Mg) content of the pyroxenes is high as in omphacitic and diopsidic pyroxenes. However, when the M1 (Fe2++Mg) content is low, as in jadeitic pyroxenes, the non-ideality of the enstatite type exchange has a marked effect on X Fe Cpx and consequently on garnet-clinopyroxene calculations.

Fate of Aflatoxin M1 in Parmesan and Mozzarella Cheese

Three batches each of Parmesan and mozzarella cheese were prepared, using milk which was naturally contaminated with aflatoxin M1. These cheeses were analyzed for aflatoxin M1 content at intervals while Parmesan was ripened for 43 weeks or mozzarella was stored for 17 weeks. There was a 5.8-fold enrichment of AFM1 in the Parmesan cheese over that in the milk from which the cheese was made. Apparent levels of aflatoxin M1 in Parmesan cheese started high, decreased until about the 22nd week of age and then slowly increased until the cheese was 43 weeks old, but the final concentration was less than that found initially. There was an 8.1-fold enrichment of AFM1 in mozzarella cheese over that in the milk from which it was made. Levels of aflatoxin M1 in mozzarella cheese varied slightly but remained near initial concentrations throughout the storage period.

Fate of Aflatoxin M1 in Cheddar Cheese and in Process Cheese Spread

Four batches of stirred-curd Cheddar cheese were prepared, using milk which was naturally contaminated with aflatoxin M1. This cheese was analyzed for aflatoxin M1 content at intervals while the cheese ripened for about 1 year. Levels of aflatoxin M1 detected in cheese started low, increased and then leveled off for the remainder of the ripening period. This cheese was used to make process cheese spread. The spread appeared to contain as much or more aflatoxin M1 as the cheese from which it was made. The aflatoxin M1 content of cheese spread appeared to increase, and then return to near original levels during storage at 7°C. Contaminated Cheddar cheese was treated with heat (90°C for 20 min), emulsifying salt (5% Na2HPO4) or both to determine the influence of processing conditions on aflatoxin M1. Samples treated with emulsifying salt or heat showed an increase in aflatoxin M1 content but not as much as when samples were treated with both. The apparent increased in aflatoxin M1 content in natural cheese and in process cheese spread may be associated with greater recovery of toxin by the analytical method as cheese ripens or is treated to make the process cheese spread.

On the presence and the content of aflatoxin M1 in milk shipped to a dairy plant (author's transl)

Between March 4 and April 15, 1976, the aflatoxin M1 content of milk shipped to a dairy plant was investigated. Out of 419 samples, 79 (19%) were positive. 33% of these samples showed values of 0.05--0.1 microng/1, 38% of more than 0.1 microng/1 and the highest value was at 0.54 microng/1. Other aflatoxins were not found. From samples of milk producers showing positive reactions, feed samples (n = 105) were taken, 45 of which (43%) were also positive. 40% of the positive samples contained up to 20 microng/kg, 36% were in the range between 20--50 microng/kg and the highest values were at 280 resp. 300 microng/kg, especially in mixed feed. Out of these samples, 47% (DLG Standard IV) resp. 36% (DLG Standard III) were higher than the tolerated maximum level of 20 microng/kg. There is a qualitative relationship between the aflatoxin M1 content in milk and the aflatoxin B1 content in feed. In 61 cases where milk samples were positive, in 41 feed samples (67%) aflatoxin B1 was detected.

Distribution of aflatoxin M1 in whey and curd during cheese processing (author's transl)

In model experiments on the distribution of aflatoxin M1 in whey and curd, the influence of the different processing steps was investigated. Taking the same weight ratio between whey and curd, the following results were obtained: a) The aflatoxin M1-distribution in whey and curd was not changed with increasing amounts of rennet, thus decreasing the renneting time at constant renneting temperatures. b) With increasing renneting temperatures, however, the toxin's percentage in the curd decreased at constant amounts of rennet, whereas the whey's content remained stable. For the commonly used temperature variations between 28 and 35 degrees C, the toxin content of the cheese varied in the range of about 12%. c) Processing of curd by acidification with different organic acids at constant temperatures did not show any change in the aflatoxin M1 distribution as compared to rennet coagulation. d) Curd processing by means of starter cultures led to a decrease in the aflatoxin M1 in curd only at higher temperatures; the toxin's percentage in whey remained practically the same. e) Washing of the curd with the 2 1/2 volumes of water decreased the aflatoxin M1 content of cheese by 22%.

Über das Vorkommen und den Gehalt von Aflatoxin M1 in Käsen des Handels

Between May 10 and August 9 1976, a total of 197 commercial cheese samples were tested on their aflatoxin M1 content; 136 samples (69%) were positive. The highest value was at 0.23 mug/kg, the average value of all positive samples was at 0.09 mug/kg. In more than half of the positive samples (54%), only traces of aflatoxin M1 could be detected, 21% contained up to 0.1 mug/kg and 14% more than 0.1 mug/kg. In soft cheese definitely less aflatoxin was found (57% positive samples) than in other cheese varieties (83--85% positive samples). Supplemental feeding of concentrates during spring season and pasture grazing of dairy cows resulted in more respectively less aflatoxin-positive cheese samples. This was especially true in soft cheese. The other cheeses with longer ripening periods showed the same effect, however, less pronounced with a clear lag phase. Inspite of many positive identity reactions on aflatoxin M1, a routine control of cheeses so far cannot be recommended because of the negative results on mass spectrometry.