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FREQUENTLY ASKED QUESTIONS
Q. What is the difference between ComBase Browser and ComBase
Predictor?
A. The ComBase Browser searches a database of kinetics
of spoilage organisms and pathogens in broth and food. The data
come from the scientific literature or were produced by miscellaneous
institutions. The ComBase Predictor gives predictions from
models based on selected data of the ComBase database as
a function of environmental factors such as temperature, pH and
water activity in broth.
COMBASE REGISTRATION PAGE
Q. Are there any costs associated with registration?
A. There is no cost associated with registering. ComBase
is jointly run by the Institute of Food Research, UK, the USDA
Eastern Regional Research Center and the University of Tasmania Food Safety Centre, Australia. It is funded by the UK Food Standards
Agency ,the USDA Agriculture Research Service, and the University of Tasmania Food Safety Centre.
Q. Why should I register?
A. We collect registration data for two main purposes: to
gain information about the customer base, e.g. which part of the
world or which industry or legislative agency are accessing the
data; and also so that we can target users with new information,
e.g. updates and improvements to ComBase. We do not disclose
submitted details to third parties. In due course we intend to introduce
a click-button for those who wish to opt out of email from us.
INTERPRETATION OF THE RESULTS
Q. What does maximum rate [ log10 (cfu/h ] mean exactly?
A. Classical predictive microbiology is based on the assumption
that the rate of growth/death of a given micro-organism in the exponential
phase is characteristic of its environment. The maximum rate is
the maximum slope of the “log(cell-conc.) versus time”
curve, in a given environment. The most important environmental
parameters are temperature, pH and water activity (a quantification
of water available to the cells). Other factors such as the concentration
of additives, preservatives, etc. may also influence the growth
rate.
Q. I get different maximum rates for the same values of temperature,
pH and water activity in the ComBase database. Which is the correct
one?
A.The growth rate not only depends on the temperature, pH
and water activity but also on other environmental factors that
are not necessarily recorded. In addition the nature of the food
can have a big influence on the rate.
Q. I get different maximum rates for the same values of temperature,
pH and water activity in the ComBase database and in ComBase predictor.
Why?
A. The predicted rates from ComBase Predictor are
from models of kinetics in laboratory media whereas some measurements
recorded in the ComBase database are in food. In addition, the models
are “fail safe”, in that they usually predict faster
growth rate or slower death rate than observed.
Q. Can you please let me know of any publications available on the
topic?
A. A document describing technical aspects of the database is
available at http://www.combase.cc/TechnDescr.pdf.
Also a list of publications can be viewed at http://www.combase.cc/about.html#publications.
QUERIES IN THE COMBASE DATABASE
Q. If no record is found for a query, does that mean that bacteria
will not grow in the given conditions?
A. “No record found” means that no record exists
within the database for that particular set of conditions. No conclusion
can be drawn from this regarding the bacterial response to the environmental
factors in question.
Q. I have tried to use ComBase, however it seems that
little information is available for spoilage organisms in real food.
A. Indeed, most of the data are on responses of pathogens observed
in laboratory media. The main reason for this is that the vast majority
of the data underlying ComBase are from the PMP (Pathogen
Modeling Program) and FMM (Food MicroModel) databases and both these
databases were primarily aimed at recognised foodborne pathogens.
However, data are constantly being added to ComBase including
microbial response records for food spoilage organisms. The database
is periodically updated and will eventually reflect these new additions.
Q. What mechanism ensures that ComBase does not include
poor quality or erroneous data?
A. The ComBase Partners conduct Quality Assurance on submitted data, with a final review done by the Institute of Food Research before data are finally published in ComBase. If data have been published in a peer-reviewed
journal, those data will be included in ComBase unchanged
(except for very obvious mistakes.) Therefore ComBase is not
different from other electronic publications.
Interpretation of the data will be highly individual and the ComBase
team assumes no responsibility for how the data are used. We recommend
that expert advice should be sought where necessary.
INTERPRETATION OF THE RESULTS AND MODELLING ASSUMPTIONS IN COMBASE PREDICTOR
ComBase Predictor has its own FAQ's section which can be found at ComBase Predictor FAQ
DATA SUBMISSION
Q. As a scientist interested in food safety, I am keen for the
results of our research to reach a wide audience. Would it be possible
for data that we have generated to be included in the ComBase
database?
A. We would be pleased to discuss this matter further to
ascertain whether a set of data is suitable for inclusion in ComBase.
If it is, we will provide spreadsheets and information describing
the format required for appropriate data entry. The real success
of ComBase is dependant upon the goodwill of those providing
data to further populate the database. In return, the relevant data
are attributed to you (or not, as you see fit).
Q. I have a dataset that I would like to submit to ComBase.
You have the growth rates already from my publications, but I'd
like to contribute the raw data.
A. It is preferable to have the original log-counts data
from which kinetic parameters (specific rates, doubling times /
D-values) were generated. We advise that you collect your data in
an appropriate format to facilitate accurate and speedy inclusion
of your data in the database. We launch a new version of the database
twice annually so there may be a delay before you can browse your
own data. Contact the ComBase team if you plan to submit your data to ComBase, or your dataset
is already there but you would like to modify or complete it.
CONTACTING COMBASE
Q. Is there a contact person for the web site?
A. You can contact the ComBase team in your region through the Contact page on this website.
