Detecting Listeria in food by keara


									                                                     Merck                                                                           1.07
                                                Newsletter for the laboratory

                    Detecting Listeria in food
                    Rapid test provides prompt diagnosis
                    Food     Listeria monocytogenes is a dangerous,     essential. The earlier the pathogen is identified,
                    highly-resistant bacterium that is endemic          the sooner corrective measures can be taken.
                    throughout the world. It can thrive and multiply    Consumers can be protected effectively, and
                    in foodstuffs that pass through the production      damage suffered by a company – both to
                    process more or less raw. In the case of pregnant   reputation and financial – can be minimized.
                    women and people with weakened immune
                    systems, infection is regarded as very serious.     Find more on Page 4
                    For the food industry, continuous checks are

                                                                         Additional topics
                                                                        Survey: Labmail well received
                                                                        Readership survey scores content and readability highly     Page 2

                                                                        Laboratory: Compulsory inspections in the laboratory
                                                                        Validation, qualification and calibration are essential
                                                                        for proper analysis                                         Page 3

                                                                        Food: Detecting Listeria in food
                                                                        Rapid test provides prompt diagnosis                        Page 4

                                                                        Analysis: Acids control in wine production
                                                                        RQeasy speeds up detection of malic acid                    Page 6

                                                                        Service: A step-by-step guide to the world of
                                                                        preparative chromatography
                                                                        New interactive CD explains preparative column packing      Page 7
Photo: Merck KGaA

                                                                        Microbiology: Monitoring powdered baby milk
                                                                        Chromocult differential medium for Enterobacter sakazakii   Page 8

                                                                        Internet innovation: The Merck4Pharma internet portal
                                                                        improves online accessibility                               Page 8

                              L’Mono test with positive result
Labmail well received
Readership survey scores content and readability highly

                                                                                                         Photo: Merck KGaA
                                                                                                                             The labmail editorial
                                                                                                                             team at the draw-
                                                                                                                             ing of the winners
                                                                                                                             (from left: Christiane
                                                                                                                             LaBelle, Martina
                                                                                                                             Andrea Lingler and
                                                                                                                             Julia Meyer).

                      Survey The editorial team at labmail was             quarters rated labmail ‘good’, with only 4%
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                      questionnaire that was included in the last issue.   covered were interesting and informative, and
                      Around one thousand of you took the time to let      commented positively on the readability of the
                      us know what you like – and don’t like – about       content. That labmail includes a wide range of
                      the newsletter.                                      themes was also well received. The vast
                      ‘It’s always good to get direct feedback from our    majority of readers mentioned that even where
                      readers’ said Christiane LaBelle, editorial team     stories were not directly concerned with their
                      member, ‘and it was particularly satisfying to       immediate area of work, they were stimulating.
                      hear that we are meeting their expectations of
Information:          labmail.’                                            New product information      Close to 30% of respondents said labmail was         Labmail is designed to inform you about new
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                                                                           to hear. In addition, the majority of survey
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                                                                           events section and the science articles included
      And the winner is …                                                  in each issue, were all useful. Suggestions for
                                                                           more items on chromatography, food &
      Everyone that returned a completed survey was
                                                                           environmental analysis and microbiology, as
      entered into a prize draw. The winners are:
                                                                           well as specialist interests such as wine analysis,
      n 1st prize – Arg Ah Bee from Singapore,                             are now being considered by the editorial team.
        won the Panasonic Lumix digital camera                             Our readership is balanced across the
      n 2nd prize – Wu Qioing Ying from Taiwan,                            pharmaceutical, chemical and food industries,
        won an iPod Nano MP3 player                                        and includes significant numbers in
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        won a spa set                                                      you have become regular readers – every 4th
                                                                           survey respondent having read all 4 issues!

2      labmail 1.07
Compulsory inspections
in the laboratory
Validation, qualification and calibration are essential for proper analysis
Laboratory         Exacting legislation requires       first step is Design Qualification (DQ), a process                            Information:
producers of pharmaceuticals to conduct regular        that shows the equipment is fit for purpose. The                    
inspections of their raw materials, intermediates      next steps are Installation Qualification (IQ) and
and end products. In order to ensure the required      Operation Qualification (OQ), which both aim
levels of accuracy, not only do analytical             to ensure that devices function correctly after
laboratories need highly qualified personnel           installation. The final step, the Performance
but they also require up-to-date software and          Qualification (PQ), takes place periodically
hardware. This is because laboratory teams must        during routine work, or sometimes before each
constantly validate, qualify and calibrate their       individual measurement.
methods and apparatus, including measuring
instruments such as weighing scales and                Merck’s unrivalled reference materials
pipettes.                                              For method validation, an inspection should
“Validation and qualification regulations are          cover e. g. accuracy, precision, linearity,
among the most strict to which analytical              repeatability and ruggedness, and should make
laboratories must adhere”, says Dr Julia               use of traceable, certified reference materials
Meyer from Merck. “In the USA and the EU,              (CRMs), such as Merck‘s Certipur reagents.

                                                                                                                 Photo: Merck KGaA
anyone applying for a licence to produce and           These are secondary materials that can be traced
sell drugs must satisfy these requirements.”           back directly to standard reference materials
Under the regulations, inspections must be             (SRM) supplied by the US National Institute of
comprehensively documented as evidence of              Standards & Technology (NIST) or the Federal
effective validation of methods and instruments.       Physical-Technical Institute (PTB).
                                                       Uniquely, Merck certifies many of its
Consistent quality assurance                           reference materials in its own accredited
Laboratory inspection procedure is determined          calibration laboratories. Both of the company‘s
by the Good Laboratory Practice (GLP) code. The        electrochemical and ICP laboratories are
first legal guidance on GLP was published in the       accredited in accordance with ISO 17025 – this
US in 1978; following this, the OECD developed         means that Merck is the only manufacturer in
a set of principles to standardize laboratory work     the world that can guarantee the trueness of its
around the world. Today, these principles have         reference materials to ISO 17025 standard, for a
been incorporated into the legal framework of          wide range of applications.
many countries.
GLP demands a thorough process of validation
and qualification, which also helps improve the
quality of inspection data. For instruments, the

  Methods                 Merck reference material          Term                           Definition
  UV/VIS                  UV/VIS standards                  DQ Design Qualification       Sets out the requirements and
  pH measurement          pH buffers                                                      specifications of the analytical device,
  Conductometry           conductivity standards                                          eg detection level
  ICP-OES/ICP-MS/AAS      single and multi element          IQ Installation Qualification Documentary evidence that the analytical
                          standards                                                       device has been delivered in the correct
  Refractometry           refractive Index standards                                      state, and conforms to the specifications
  Differential scanning                                     OQ Operation Qualification    Documentary evidence of the operational
  calorimetry             DSC standards                                                   capability of the analytical device
  Ion chromatography      ion standards                     PQ Performance Qualification Documentary evidence of the operational
  Titration               volumetric standards                                            capability of the analytical device during
                                                                                          routine operation

                                                                                                                                     labmail 1.07       3
                    Food safety
                    Faster, more secure identification of Listeria monocytogenes

                                                                  A significant challenge
                                                                  Listeria monocytogenes is principally found in
                                                                  foods that are not heated to high temperatures
                                                                  during processing. These include unpasteurised
                                                                  milk cheeses, minced meats, smoked salmon
                                                                  and some ‘convenience foods’. The greater the
                                                                  number of production stages between original
Photo: Merck KGaA

                    4   labmail 1.07
                                                                                                              Photo: Merck KGaA
and final product, as with ready-to-eat but raw
products, for example, the higher the risk that
pathogenic bacteria are present and able to grow.
The post-infection death rate is exceptionally
high. In the United States of America, there are
only 2,500 new cases of listeria infection each
year, but almost 20 percent of these are fatal. By                                                            L’Mono test with
way of comparison, the number of Salmonella                                                                   negative result
infections is 1.4 million per annum, though the
death rate is just 550. Other pathogenic bacteria
that can occur in foods, such as Campylobacter       user that the test has been successful. As Jörg
or E. coli, are also less aggressive. In addition,   Slaghuis explains, “Users can be sure that they
destroying L. monocytogenes is a significant         have carried out the test correctly, and that the
challenge, as organisms can replicate at a           correct quantity of sample was applied. This
temperature of only two degrees. Even a closed       practically rules out the possibility of false results
cool chain is not effective.                         caused by incorrect handling.”

Listeria as a yardstick of hygiene                   Proof positive
Continuous checks for the presence of Listeria       A study carried out by Professor Michael Bülte,
have become routine for the food industry, and       of the Institute for Veterinary Nutrition at the
the presence of any strain of the bacteria serves    Justus-Liebig-Universität in Giessen, Germany
as a yardstick of hygiene.                           has demonstrated that the test is not only rapid,
In order to ensure that the checks are               but that it is reliable as well. Summarizing the
reliable, five samples of 25 grams each must         results of his tests, Professor Bülte stated that
be examined. No sample that is capable of            “After 48 hours’ enrichment, this simple-to-apply
supporting Listeria must be found to contain the     test provided the correct result in all cases”.
bacteria. “Irrespective of the strain, if Listeria
is found, it means that there are problems with
regard to hygiene…” explains Dr Jörg Slaghuis,
Head of Laboratory Immunological Rapid Tests,
“…but it is more important to know whether
Listeria monocytogenes is present.”
Establishing this has traditionally been a process              Rapid tests for pathogens in
that takes up to five days to give a clear result.              foods and the
Valuable time was lost, during which the bacteria
could reproduce more extensively. Many tests
                                                                Merck provides a range of rapid tests for
simply confirm the presence of Listeria, without
                                                                pathogenic bacteria, including:
differentiating between the different strains.
                                                                n E. coli 0157
New direct test                                                 n Verotoxin producing E. coli
Now, Merck’s Lateral Flow Test directly                         n Salmonella
demonstrates the presence of Listeria                           n Campylobacter
monocytogenes in food samples. Merck                            n Listeria
also supplies everything that is required for                   n Listeria monocytogenes
enrichment, detection and verification.                         n Legionella
All components are designed to work together                    n Enterotoxinogenic Bacillus cereus
to eliminate any false positive or false negative
results. An internal control confirms to the

                                                                                                                 labmail 1.07     5
                                    Acids control in wine production
                                    RQeasy speeds up detection of malic acid

                                    Information:             Analysis Acids, together with residual
                                   sugars and alcohol, are central elements that          The RQeasy test solves this problem by
                                                             contribute to the taste and character of wine.         allowing winemakers to measure malic acid
                                                             But if it is too acidic, a wine can taste sharp,       content on site. Such rapid determination
                                                             strong and unpleasant; this is particularly true       greatly improves the process, allowing the
                                                             with too much malic acid, a naturally occurring        winemaker to:
                                                             constituent of grapes.
                                                             Merck’s RQeasy is a rapid, on-the-spot test for        n Determine the optimum point at which to
                                                             malic acid content. RQeasy avoids the inevitable          end the decomposition process.
                                                             delays associated with external testing; this is       n Move on to the next stages of produc-
                                                             a major advantage for the winemaker, as malic            tion – such as sulfurating and bottling
                                                             acid data is essential for many time-critical            – immediately after acid decomposition
                                                             aspects of production.                                   has ceased.
Photo: Merck KGaA

                                                                                                                    n Ensure the absence of malic acid before
                                                             Harnessing a natural process                             bottling – in warm regions, it is par-
                                                             When malic acid is converted by bacteria                 ticularly important that wine contains
                           Acid is essential for             into lactic acid, the wine gains a much softer           no malic acid before bottling as there is
                           the taste of wine, but            character. Wine producers first observed this            a danger that remaining malic acid will
                           with too much acid                                                                         continue to decompose, adversely affect-
                                                             process in the mid-20th century, noticing that
                           it tastes unpleasant.
                                                             spontaneous biological acid decomposition                ing the taste.
                                                             occurred when temperatures rose in springtime.         n Reduce time to market. Faced with
                                                             Today, malolactic acid conversion is a standard          increasing economic pressure, it is
                                                             process in the manufacture of red wine. After            becoming increasingly important that
                                                             fermentation, winemakers specifically trigger            winemakers get their bottles into the
                                                             malolactic conversion by heating the wine and            shops as fast as possible.
                                                             – in some cases – by injecting it with lactic acid
                                                             A side effect, however, is the removal of fruit
                                                             aromas so traditionally the process has rarely       a fruit bouquet is highly regarded. But as
                                                             been used in white wine production, where            consumers become ever more sensitive to acid
                                                                                                                  in wine, the use of malolactic fermentation has
                                                                                                                  increased in this sector too.

                                    The new RQeasy                                                                Controlled acid decomposition
                                    Malic for detection of                                                        In the acid conversion process, lactic acid
                                    malic acid.
                                                                                                                  bacteria produce CO2, resulting in the formation
                                                                                                                  of bubbles. Successful decomposition cannot,
                                                                                                                  however, be determined by visual inspection
                                                                                                                  alone as bubbling can also stem from other
                                                                                                                  reactions. Instead, acid conversion testing
                                                                                                                  requires the regular measurement of malic acid
                                                                                                                  Larger vineyards often have their own
       Photo: Merck KGaA

                                                                                                                  laboratories for this task, but smaller winemakers
                                                                                                                  generally rely on external testing, which
                                                                                                                  can waste valuable time. Biological acid
                                                                                                                  decomposition generally takes between ten and
                                                                                                                  forty days, and so if a winemaker has to wait a
                                                                                                                  few days for measurement results, the data may
                                                                                                                  be obsolete by the time it is received.

                                    6        labmail 1.07
                    A step-by-step guide to the world of
                    preparative chromatography
                    New interactive CD explains preparative column packing
                                                                        Users are also given helpful advice on the
                                                                        procedure itself. For example, the CD explains
Photo: Merck KGaA

                                                                        that the packing material should never be stirred
                                                                        with a magnetic stirrer when preparing the
                                                                        suspension, as this can create shear forces that
                                                                        may damage the material.
                                                                        It also explains how a vacuum can be created
                                                                        and the desired compression pressure retained.
                                                                        Finally, the CD describes how to clean the
                                                                        chromatography column, and how to prepare it
                                                                        for future use.

                                                                        Individual training
                                                                        “Customers have often asked if we could
                                                                        provide a flexible means of explaining standard
                                                                        chromatography methods, so that staff could be
                                     To obtain the CD, please send an   trained at a place and time to suit them best”,
                                     e-mail to       says Frank Appel, Marekting Manager Process
                                                                        Separations. “The CD answers this need. Now
                                                                        all laboratory employees can be trained on site,
                                                                        without significant additional expense.”
                    Service      How do you pack columns for            And it‘s not only newcomers to chromatography
                    preparative chromatography in the laboratory?       who can benefit. There is also a wealth of
                    For experienced laboratory staff this is a          general information on the subject, details of
                    straightforward and routine task. However, for      additional and replacement components, and
                    new employees, or those who only occasionally       technical handbooks (in PDF Format), providing
                    require a chromatography column, this could be      an extra resource for more experienced users.
                    an unfamiliar process.
                    Now Merck has compiled an interactive CD
                    that provides a step-by-step guide on how to
                                                                                                                            Every working step is
                    pack columns for preparative chromatography.                                                            precisely explained
                    “The CD not only enables new employees to                                                               and illustrated on
                    learn the process, but also provides invaluable                                                         the CD
                    information for experienced users”, explains
                    Dr Michael Schulte, Merck Director of Research
                    and Development.

                    Each click brings you closer to the
                    finished column
                    The CD begins by describing the components
                    that make up the column, what columns look
                    like, and how they can be properly linked. Users
                    can identify component names by moving the
                    mouse over an interactive picture. By clicking
                    on the corresponding term in the text, the
                                                                                                                                                    Photo: Merck KGaA

                    component within the picture turns red. At the
                    next stage, the components of the column are
                    assembled to form a complete picture.

                                                                                                                            labmail 1.07        7
        Monitoring powdered baby milk
        Chromocult medium for detection of Enterobacter sakazakii

        Microbiology            Powdered infant milk        survivers severe lasting complications can result.                                          Published by
        formula is not sterile and may occasionally         A report by the FAO and WHO recommends
                                                                                                                                                        Merck KGaA
        contain pathogens. Intrinsic contamination with     that the infant food industry should implement                                              Performance &
        Enterobacter sakazakii is of particular concern     environmental monitoring programmes                                                         Life Science Chemicals
                                                                                                                                                        Frankfurter Straße 250
        as infection in infants can lead to serious         to reduce the prevalence of E. sakazakii in                                                 64293 Darmstadt · Germany
        developmental problems, and even death.             powdered baby milk. The report advises                                            
        The mortality rate is very high. 20 – 50 % of the   that Enterobacteriaceae should be used as
                                                                                                                                                        Editing: Merck KGaA +
        infants who contracted the disease died and for     an indicator of hygiene control in factory                                                  Profilwerkstatt
                                                            production lines.
                                                                                                                                                        Layout: Profilwerkstatt,
                                                            Merck offers many innovative products for                                                   Corporate Publishing,
labmail 1.07 is also online                                 microbiological analysis in the food industry,                                              64295 Darmstadt
                                                            including the Chromocult E. sakazakii Agar. This
                                                                                                                                                        Photos: Merck KGaA
With immediate effect, an electronic version of labmail     differential medium is ideal for the detection in
1.07 is available unter            infant food and hygenic control in baby milk                                                Printing: Frotscher Druck GmbH,
Just click on the name to view the content.                 production - E. sakazakii colonies are easily
                                        Your labmail team   identified by a color change from blue to green,
                                                            while other bacteria are inhibited or grow

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Internet innovation              The Merck4Pharma           Feb 25–
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internet portal greatly simplifies customer access
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by providing a simple means of accessing                                              Annual Meeting & Exposition
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        8       labmail 1.07

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