Technical Directory
Introduction.
Bactron is the unique antimicrobial agent used in the Biosan range of water based
hygiene coatings. The purpose of this document is to explain, substantiate and where
appropriate quantify the properties of Bactron; primarily but not exclusively in the
context of Biosan.
An overview of Bactron.
Bactron is a microbiologically active liquid concentrate based on a unique (patent
pending) formula that imparts exceptional bactericidal properties when incorporated
into a finished product. Although initially developed for use in paint, Bactron can be
added to a wide range of polymer and mineral based products including mastics,
sealants, grouts, plastics and adhesives.
The principal active ingredient in Bactron has been shown to be effective against a
wide range of bacteria including ‘super bugs’. The technology is well understood and
has proven safe over the 40 years of its use, gaining food contact approval in both the
USA and EU. Importantly, scientific opinion concludes that bacteria cannot develop
resistance to this technology, as they have been able to do to certain antibiotics.
Traditionally the active ingredient has been dispersed into finished products as a dry
white powder. The uniqueness of Bactron comes from the fact that the (patent
pending) technology enables the active ingredient to be dissolved into an almost
‘water white’ solution, which is then added to the product. This has two principal
benefits: 

It greatly simplifies the manufacturing process of a product with antimicrobial
properties.
Tests undertaken by an independent DEFRA approved microbiological testing
laboratory, prove that the antibacterial properties of Bactron show significant
improvement over the powder itself. Primarily this is because the active
ingredient contained in Bactron becomes homogenously distributed and is able
to migrate more effectively through the host material.
Adding Bactron does not affect the finished product adversely in any way and at the
levels of incorporation safety data sheets and labels need not refer to its presence.
Bactron exhibits the following notable benefits: 




Bactron is effective against a wide range of gram positive and gram negative
bacteria and viruses (see Section 1).
Bactron does not contribute to the evolution of resistant strains of bacteria (see
Section 2).
Bactron is safe (see Section 3).
Bactron lasts for the normal service life of the treated product (see Section 4).
Bactron is verified by independent testing (see Section 5).
Section 1 : Bactron is effective against a wide range of gram positive and gram
negative bacteria and viruses.
The mechanism of action:The antimicrobial agent in Bactron is incorporated into coatings at the level of 5000
parts per million. This level far exceeds the minimum inhibitory concentration (MIC)
required for an inhibitory antimicrobial effect. (see appendix 1:1).
Studies have shown that the active ingredient in Bactron is effective against a wide
range of gram positive and gram negative bacteria (including antibiotic resistant
strains) and viruses that are important in personal and public hygiene. These include
opportunist, transient and pathogenic (disease causing) bacteria.
Bactron kills through a variety of different mechanisms. One of the ways that Bactron
kills microbes is by acting on the cytoplasmic membrane of the cells, preventing the
uptake of essential amino acids. This disorganization causes leakage of the low
molecular weight cellular contents, bringing about the death of the micro organism.
There are a number of other documented mechanisms by which cells are killed, which
explains why Bactron works even when certain enzymes are absent from the micro
organism.
Incorporation into coatings (Biosan):Bactron is added to the aqueous phase (liquid paint) consisting of the resin, pigment
and solvent (water in the case of Biosan).
The resin and pigments in the liquid paint are surrounded and partly penetrated by
Bactron, which has an affinity for the polymer. Hence Bactron becomes an integral
part of the continuous paint film. Bactron permeates the film and because of the
(patent pending) technology, it retains sufficient mobility within the dry film to be
able to diffuse to the surface or any other areas of the coating that have become
depleted due to wear, tear and mechanical damage. The way in which Bactron is
incorporated in the host product and its ability to ‘recharge’ challenged areas, makes it
uniquely effective at controlling micro organisms (see appendix 1:2).
The antimicrobial effectiveness of Bactron in Biosan can be demonstrated by two
experiments undertaken by an independent DEFRA approved microbiologist:-
1/ The 24 Hour Halo Test on Staphylococcus aureus ATCC 6538 Using a Test
Method Based on AATCC 90:The effectiveness of Bactron in Biosan can be shown qualitatively by the 24 hour halo
test experiment. In this test, two sample disks coated in the same host paint product
were placed in petri dishes containing nutrient agar inoculated with Staphylococcus
aureus. Paint sample B contained Bactron, paint sample A remained as the control
(benchmark).
The Halo Test.
Paint Sample B : Containing Bactron.
Paint Sample A : The Unmodified Control
After 24 hours incubation a zone free of Staphylococcus aureus growth was evident
around sample B. This zone of inhibition or ‘halo’ is a qualitative representation of
the antimicrobial effectiveness of Bactron when compared with sample A.
The results for this experiment can be broadly quantified by measuring the halo in
millimetres from the edge of the sample to the edge of the bacterial growth. The larger
the halo, the more effectively the bacteria have been inhibited or controlled over the
24 hour period.
2/ The 7 day Bactericidal Activity Test on Staphylococcus aureus ATCC 6538 Using
a Test Method Based on AATCC 100.
In this test sample disks coated in the same host paint product were inoculated with a
liquid culture containing 560,000 CFU’s of Staphylococcus aureus. Paint sample B
contained Bactron, paint sample A remained as the control (benchmark). The number
of CFU’s of bacteria in each case, were counted at 24 hour, 72 hour and 7 day time
intervals following inoculation.
The 7 Day Bactericidal Activity Test for Biosan Ultra.
Product
Number of CFU’s
expressed linearly
Number of CFU’s
expressed as an
index
Biosan Ultra with
Bactron @ 24hrs
94,000
9.4 x 104
Number of
CFU’s
expressed
logarithmically
4.97
Unmodified Control
@ 24hrs
100,000
1.0 x 105
5
Biosan Ultra with
Bactron @ 72hrs
360
3.6 x 102
2.56
Unmodified Control
@ 72hrs
18,000
1.8 x 104
4.26
Biosan Ultra with
Bactron @ 7 days
<10
<10
<1
Unmodified Control
@ 7 days
7,100
7.1 x 103
3.85
The results of this experiment can be shown graphically using the logarithmic scale as
per industry standards:-
Biosan Ultra.: Graphical Representation of The 7 day Bactericidal Activity Test.on
Staphylococcus aureus ATCC 6538 Using a Test Method Based on AATCC 100.
The experiment shows that after the initial 48 hour period 99% of bacteria have been
killed by the sample containing Bactron, with numbers of bacteria declining from
560,000 to approximately 5000 CFU’s. After 7 days the bacteria cannot be detected
on the Bactron protected sample whereas significant numbers of potentially
pathogenic bacteria are still surviving on the unprotected coating.
Based on the results of this experiment it can be stated that after 7 days, Biosan Ultra
containing Bactron antibacterial protection has reduced the bacteria count by greater
than a log reduction of 4.75. By way of comparison, the unprotected control has
reduced the bacteria count by less than a log reduction of 2.
These results enable us to conclude that ‘the antimicrobial treated product (Biosan
with Bactron) exhibits excellent bacteriostatic and bactericidal activity,’ as verified
by a DEFRA approved microbiologist commissioned to undertake independent testing
on the Biosan range (see Section 5).
Section 2 : Bactron does not contribute to the evolution of resistant strains of
bacteria.
Bactron’s active ingredient has been widely used for almost forty years without any
convincing evidence of resistant strains of bacteria being encountered in real life
situations.
The emergence of resistant strains of bacteria is a significant health issue that relates
to the over prescription of antibiotics and the incorrect usage of disinfectants. Bactron
contains an antimicrobial agent used at bactericidal concentrations; it is not an
antibiotic. In fact, the active ingredient in Bactron has been used successfully in
hospitals to control outbreaks of the antibiotic resistant strains of the bacteria
‘Methicillin Resistant Staphylococcus aureus (MRSA)’.
Scientific opinion concludes that bacteria cannot develop resistance to Bactron for
two principal reasons (see appendix 2:1:1):1/ The level of incorporation.
Bactron is incorporated into coatings at a level of 5000ppm. This level far exceeds the
minimum inhibitory concentrations and so kills the micro organisms outright (see
appendix 1:1). If the bacteria are killed outright there is no theoretical possibility of
these bacteria being able to pass on any form of resistance to a subsequent generation.
2/ The multifaceted mechanisms of action.
Evidence published over a number of years shows that Bactron’s active ingredient
kills bacteria in a variety of different ways. These varied mechanisms ultimately result
in a breakdown or failure in the organism’s cell wall. Cell wall failure affects the
bacteria’s most vital processes and ultimately causes cell death. As there is no single
mechanism of action it is not possible for a specific resistance to be developed.
The European Commission has asked its Scientific Steering Committee (SSC) for an
opinion on whether the active ingredient in Bactron could lead to the development of
resistant strains of bacteria. Their report was adopted at a meeting held in July 2002
and concluded that:‘There is no convincing evidence that the active ingredient in Bactron poses any risk
to humans or to the environment by inducing or transmitting antibacterial resistance
under current conditions of use.’
In 1997 the US Food & Drug Administration convened an independent panel to
determine whether antimicrobial products presented any risk of promoting antibiotic
resistance. This panel also concluded that there was no evidence linking the use of
antimicrobial products with antibiotic resistance.
Section 3 : Bactron is Safe.
Bactron is not classified as harmful to humans and as the likely human exposure
levels due to handling products that contain Bactron are extremely low, it is
completely safe to do so.
The active ingredient has an extensive safety record and is regarded as being so safe
that it is widely used in personal care products such as mouthwash, toothpaste, liquid
soap and deodorant. There are extensive publications relating to its toxicology and
efficacy.
The antimicrobial contained in Bactron conforms to the safety requirements of the
United States Pharmacopeia (USP26) Antimicrobial Effectiveness Test and each
batch of the ingredient is certified as pure by an independent analytical laboratory.
Bactron is manufactured to our own recipe by an ISO9002 accredited company.
Separate studies have shown that Bactron’s ingredients, when diluted in the
environment, are biodegradable and do not accumulate because biological and
photolytic processes break them down. Additionally, as Bactron forms an integral part
of the coating and is only added as a tiny percentage, any concentration present in the
environment is negligible.
Regulatory information
Bactron is recommended as an additive for paints that are intended for use as
disinfectants or sterilants to control bacteria or viruses. As such Bactron does not fall
within the scope of The Control of Pesticides Regulations 1986.
Products modified with Bactron do fall within the remit of the Biocidal Products
Directive (98/8/EC) as implemented in the UK by the Biocidal Products Regulations
2001.
Under the EC Review of Existing Biocidal Active Substances : First Review
Regulations (1996/2000), producers and/or formulators of biocidal active substances
were required to inform the European Chemicals Bureau. This was done for the active
component of Bactron in 1999.
As the antimicrobial in Bactron is included in the preliminary list of the European
Chemicals Bureau, it means that products containing it may be marketed in member
states of the EC, subject to any existing national legislation, until a decision is made
on the antimicrobials included in the list. The Directive gives 10 years for all existing
antimicrobials to be reviewed and there is no reason to believe that the status of the
antimicrobial in Bactron will not be confirmed following the review.
Bactron is also registered with the UK National Poisons Information Service because
of the biocidal activity of the product and not because of any hazards relating to its
use or composition.
4. Bactron lasts for the normal service life of the host product.
The resin and pigments are surrounded and partly penetrated by Bactron, which has
an affinity for the polymer yet remains able to diffuse evenly throughout the coating.
Bactron is only removed at the surface of the coating in negligible amounts through
wear, cleaning and it’s bactericidal action. The unique property of Bactron to migrate
through the coating to recharge depleted areas means that antimicrobial protection is
constantly maintained (see appendix 1:2).
The relatively high level of Bactron in the coating (5000ppm of the active ingredient)
is far in excess of the minimum inhibitory concentrations to micro organisms and this
reservoir is sufficient to recharge depleted areas for at least the normal service life of
the host product (see appendix 1:1).
Scientific opinion states that at the recommended level of incorporation there is
sufficient Bactron present in a host product to exert a broad spectrum antimicrobial
action for at least 5 years (see appendix 2:1:2). This would exceed the normal service
life of a coating in a hygiene sensitive area.
5 : Bactron is verified by independent testing.
All testing on Bactron in Biosan hygiene coatings has been undertaken by a DEFRA
approved microbiologist:
Appendix 1:1.
BACTRON™ efficacy
The minimum inhibitory concentrations for the active ingredient of Bactron™ are
shown below for a wide range of standard strains of micro organisms that are of
importance to hygiene and public health.
The antimicrobial content of Bactron™ containing coatings is 5000ppm. This is the
reservoir of active ingredient that gives the coating the ability to remain active
throughout its service life.
Gram-positive bacteria
Bacillus cereus
Bacillus cereus var.mycoides
Bacillus megatherium
Bacillus pumilus
Bacillus subtilis
Bacillus subtilis
Bacillus subtilis
Brevibacterium ammoniagenes
Clostridium botulinum
Clostridium tetani
Corynebacterium acnes
(Propionibacterium acnes)
Corynebacterium diphtheriae
Corynebacterium diphtheriae
Corynebacterium diphtheriae
Corynebacterium melassecola
Corynebacterium minutissium
Corynebacterium minutissium
Diplococcus pneumoniae
Enterococcus faecalis
Enterococcus faecalis
Enterococcus faecalis
Enterococcus faecalis
Lactobacillus arabinosus
Lactobacillus arabinosus
Lactobacillus fermenti
Listeria monocytogenes
Listeria monocytogenes
Micrococcus luteus
Micrococcus luteus
Mycobacterium phlei
Mycobacterium smegmatis
Mycobacterium tuberculosis
Propionibacterium acnes
Sarcina lutea
Sarcina ureae
Strain
A
A
A
ATCC 7061
ATCC 6051
ATCC 6633
NCTC 8236
ATCC 6871
NCTC 3805
NCTC 9571
ATCC 6919
MIC ( ppm )
3
3
3
0.3
0.1
0.3
0.1
1.0
3
3
3
A
ATCC 6917
NCTC 3984
ATCC 17965
ATCC 23348
ATCC 6501
NCTC 7465
ATCC 10541
ATCC 29212
ATCC 6055
ATCC 6057
ATCC 8014
CITM 706
CITM 707
ATCC 15313
NCTC 7973
ATCC 7468
ATCC 9341
A
NCTC 8152
A
ATCC 6919
NCTC 196
ATCC 6473
3
3
3
3.0
3.0
5
3
3.0
4.0
5.0
3.0
33
33
33
1.0
1.0
3.0
1.0
0.3
1
100
3.0
3
0.1
Sporosarcina ureae
Staphylococcus albus
Staphylococcus albus
Staphylococcus aureas
Staphylococcus aureas
Staphylococcus aureas
Staphylococcus aureas
Staphylococcus aureas
Staphylococcus aureas
Staphylococcus aureus
Staphylococcus aureus
Staphylococcus aureus
Staphylococcus aureus
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus hominis
Streptococcus agalactiae
Streptococcus faecalis
Streptococcus faecalis
Streptococcus haemolyticus A
Streptococcus haemolyticus A
Streptococcus pyogenes
Streptococcus pyogenes
ATCC 6473
C
NCTC 7292
ATCC 13709
ATCC 6538
NCTC 4163
NCTC 6571
NCTC 6966
NCTC 7447
ATCC 13709
ATCC 6538
ATCC 9144
NCTC 4136
NCTC 6571
ATCC 1228
ATCC 27844
NCTC 8181
ATCC 10541
NCTC 8619
A
A
ATCC 9342
NCTC 8322
1.0
0.03
0.1
0.01
0. 01
0.01
0.03
0.1
0.01
0.01
0.01
0.05
0.03
0.03
0.01
1.0
3
3
10
1
3
3.0
3
Gram-negative bacteria
Aerobacter aerogenes
Aerobacter aerogenes
Alcaligenes faecalis
Brucella abortus
Brucella intermedia
Brucella melitensis
Brucella suis
Cloaca cloacae
Enterobacter cloacae
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Escherichia coli
Haem. ophilus influenzae
Kiebsiella aerogenes
Kiebsiella pneumoniae
Strain
CITM 413
CITM 812
A
NCTC 8226
A
A
A
NCTC 8155
ATCC 13047
A
ATCC 10536
ATCC 11229
ATCC 25922
ATCC 4157
ATCC 9661
ATCC 9663
NCTC 8196
NCTC 86
NCTC 9001
A
NCTC 8172
ATCC 4352
MIC ( ppm )
1
1-3
>100
0.1
0.1
0.1
0.03
0.3
0.5
0.3
0.5
0.3
0.3
0.3
0.3
0.3
0.03
0.1
0.1
33
0.3
0.3
Gram-negative bacteria
Klebsiella aerogenes
Klebsiella edwardsii
Klebsiella pneumoniae
Klebsiella pneumoniae
Legionella pneumoniae (isolate)
Loefflerella mallei
Loefflerella pseudomallei
Moraxella duplex
Moraxella glucidolytica
Moraxella Iwoffi
Neisseria catarrhalis
Pasteurela pseudotuberculosis
Pasteurella septica
Proteus mirabilis
Proteus mirabilis
Proteus mirabilis
Proteus vulgaris
Proteus vulgaris
Proteus vulgaris
Proteus vulgaris
Proteus vulgaris (Neotype)
Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas capacia
Pseudomonas fluorescens
Pseudomonas fluorescens
Salmonella choleraesuis
Salmonella enteritidis
Salmonella enteritidis
Salmonella paratyphi
Salmonella paratyphi A
Salmonella paratyphi B
Salmonella paratyphi B
Salmonella paratyphi B
Salmonella pullorum
Salmonella typhi
Salmonella typhi
Salmonella typhi
Salmonella typhi
Salmonella typhimurium
Salmonella typhimurium
Serratia marcescens
Serratia marcescens
Shigella dysenteriae
Strain
ATCC 13048
NCTC 7242
ATCC 10031
ATCC 4352
A
NCTC 9674
NCIB 10230
A
A
A
NCTC 3622
C
NCTC 948
A
ATCC 14153
NCTC 8309
ATCC 13315
ATCC 6896
NCTC 4636
NCTC 8313
NCTC 4175
ATCC 12055
ATCC 15442
ATCC 19582
NCTC 1999
NCTC 8060
C-175
ATCC 17397
NCTC 4755
ATCC 1078
A
A
NCTC 5704
NCTC 5322
A
NCTC 3176
NCTC 5704
ATCC 9120
A
ATCC 6539
NCTC 786
NCTC 8384
ATCC 13311
NCTC 5710
A
ATCC 13880
NCTC 2249
MIC ( ppm )
0.5
0.3
0.2
0.3
10
0.3
1
0.01
0.3
0.1
33
10
0.1
0.3
0.5
0.3
0.3
0.3
0.3
0.1
0.01
>1000
> 500
> 500
> 100
>1000
256
> 500
> 100
0.3
0.1
0.3
0.1
0.3
0.1
0.3
0.1
0.3
0.1
0.3
0.3
0.3
0.3
0.3
> 100
> 500
0.1
Gram-negative bacteria
Shigella flexneri
Shigella flexneri
Shigella flexneri
Shigella sonnei
Vibrio cholerae
Vibrio eltor
Strain
NCTC 8192
NCTC 8204
NCTC 8205
NCTC 7240
A
NCTC 8457
MIC ( ppm )
0.3
0.1
0.1
0.1
10
10
Moulds and yeasts
Aspergillus flavus
Aspergillus fumigatus
Aspergillus niger
Aspergillus terreus
Aspergillus versicolor
Candida albicans
Candida albicans
Candida albicans
Epidermophyton floccosum
Keratinomyces ajelloi
Microsporum canis
Microsporum gypseum
Pityrosporum ovale
Saccharomyces cerevisiae
Trichophyton mentagrophytes
Trichophyton rubrum
Trichophyton rubrum
Trichophyton tonsurans
Strain
ATCC 9643
ATCC 9197
ATCC 6275
ATCC 10690
ATCC 11730
A
ATCC 10231
ATCC 10259
ATCC 10227
A
ATCC 10214
ATCC 6286
ATCC 14521
ATCC 2601
ATCC 9533
A
ATCC 10218
A
MIC ( ppm )
10
10
30
30
10
3
3.0
3.0
1-10
10
3.0
3.
10
10
1.0
10
3.0
10
Origin of the Strains:
CITM
official culture collections
NCTC
official culture collections
ATCC
official culture collections
C
Ciba
A
Bacteriological or veterinary institute
Appendix 1:2
Liquid Paint.
The aqueous phase contains, amongst other things:- Bactron, resin and pigment. The
resin and pigments in the liquid paint are surrounded and partly penetrated by
Bactron, which has an affinity for the polymer.
Dry Paint Film.
Bactron permeates and becomes an integral part of the dry film.
Because of the (patent pending) technology, Bactron retains sufficient mobility to
diffuse to the surface or any other areas of the coating that have become depleted.
Consequently, Bactron is able to recharge challenged areas, making it uniquely
effective at controlling bacteria.
Appendix 1:3
An explanation of logarithmic scales.
Scientific protocol calls for a logarithmic scale rather than a linear scale to be used
when representing graphically the decline in the number of CFU’s of bacteria.
This can be confusing but in essence the vertical scale of the graph can be explained
as follows:Log 1 = 101 =
Log 2 = 102 =
Log 3 = 103 =
Log 4 = 104 =
Log 5 = 105 =
Log 6 = 106 =
10 x 1 =10
10 x 10 = 100
10 x 10 x 10 = 1,000
10 x 10 x 10 x 10 = 10,000
10 x 10 x 10 x 10 x 10 = 100,000
10 x 10 x 10 x 10 x 10 x 10 = 1,000,000
Both the Bactron protected sample and the control were placed in perti dishes
containing nutrient agar inoculated with approximately 560,000 CFU’s of
Staphylococcus aureus; 560,000 transcribed onto the vertical scale of the graph falls
between the points 105 and 10 6. Expressed as a logarithmic figure 560,000 equates to
5.75.
Over a seven day period the sample containing Bactron reduced the number of CFU’s
of bacteria to a point below 101; this equates to less than 10 when transcribed to a
linear scale.
Over the same seven day period the unmodified sample, largely as a result of the
presence of relatively short acting ‘in can’ preservatives, reduced the number of
CFU’s of bacteria to a point below 10 4; this equates to more than 7000 when
transcribed to a linear scale.
A log reduction takes place when the number of bacteria drops by one logarithmic
value. Eg ; a log reduction of 1 takes place when the value falls from 106 to 105; a log
reduction of 2 takes place when the value falls from 106 to 104 and so on.
Appendix 2:1
2:1:1
‘Bactron Solution is a broad spectrum antimicrobial preparation, effective against a
wide range of bacteria and fungi.
At the biocidal concentrations of Bactron used in application, the main ingredient is
non specific and acts by rupturing the cell wall of the micro organism with resultant
and fatal lysis of the cell contents.
At sub lethal inhibitory levels, studies also suggest that the antimicrobial agent
inhibits growth by blocking microbial enzymes responsible for essential fatty acid and
lipid biosynthesis.
As a consequence of this multi level mode of action, the development of tolerant or
resistant strains is highly unlikely; as has proved to be the case under practical
conditions of usage for many years in a variety of applications1.’
2:1:2.
‘It is my considered opinion that surface coatings protected with the recommended
level of Bactron will, under normal conditions of service, continue to exert a broad
spectrum antimicrobial action for 5 years or the lifetime of the coating, whichever is
shorter1.’
1
Ashley Cox. MSc. C.Chem. MRSC. M.I.BIOL.
Glossary of Key Terms
AATCC – American Association of Textile Colour Chemists. An accepted testing
protocol.
ATCC – American Type Culture Collection. ATCC 6538 is the particular strain of
Staphylococcus aureus tested.
Algae – Members of a group of predominantly aquatic, photosynthetic organisms of
the kingdom protista that can also inhabit areas such as damp walls, tree trunks and
soil.
Amino Acid – Organic compounds containing an amino group and a carboxylic acid
group; proteins are composed of various proportions of about 20 common amino
acids.
Antibiotic – Chemical substances produced by living organisms such as moulds and
bacteria, or synthesised in laboratories for the purpose of destroying or preventing the
growth of bacteria that cause disease.
Bactericidal – Capable of killing bacteria.
Bacteriostatic – Arrests the growth of bacteria.
Bacteria – Usually single celled spherical, spiral or rod shaped organisms lacking
chlorophyll that reproduce by fission. Important as pathogens and for biochemical
properties.
Bactron – The unique antimicrobial additive used in Biosan.
Biosan – A unique range of water based hygiene coatings containing Bactron.
Cell – The basic structural and functional unit of all organisms; cells may exist as
independent units of life or may form colonies or tissues in higher plants and animals.
Colony Forming Unit (CFU) – An individual cell, which is able to reproduce itself
into an entire colony of identical cells.
Control (Benchmark) – A method in which hypothesis are tested by comparing two or
more populations that are similar or identical in most respects other than that which
has been identified as the independent variable.
Cytoplasm – The protoplasm of the cell excluding the nucleus.
Cytoplasmic membrane – The membrane that surrounds the cell’s cytoplasm
separating it from the environment. It consists of a double layer of phospholipids and
has proteins embedded in it.
DEFRA – The Department for Environment, Food & Rural Affairs. The government
body overseeing the regulation of food issues in the UK including animal welfare,
safety standards and environmental issues.
DNA – A nucleic acid found in the nucleus of a cell and consisting of a polymer
formed from nucleotide and shaped like a double helix; associated with the
transmission of genetic information; ‘DNA is the king of molecules’.
Enzymes – Any of several complex proteins that are produced by cells and act as
catalysts in specific biochemical reactions.
Fission - Reproduction by splitting into equal parts.
Gram Positive – A prokaryotic cell who’s cell wall stains purple (positive) in Gram
stain. The cell wall of a gram positive bacterium consists chiefly of peptidoglycan and
lacks the outer membrane of gram negative cells.
Gram Negative – A prokaryotic cell who’s cell wall stains pink (negative) in Gram
stain. The cell wall of a gram negative bacterium contains relatively little
peptidoglycan but contains an outer membrane composed of lipopolysaccharide
(LPS), lipoprotein and other complex macromolecules.
Logarithmic scale – A scale on which actual distances from the origin are
proportional to the logarithms of the corresponding scale numbers (see appendix 1:3).
Minimum inhibitory requirement – The minimum amount of an active ingredient
needed to control a particular strain of bacteria. Normally expressed in parts per
million (ppm).
Mould – A fungus that produces a superficial growth on various kinds of damp or
decaying organic matter.
Nucleus – A part of the cell containing DNA and RNA and responsible for growth
and reproduction.
Nutrient Agar – A nutritive culture medium that uses agar as the gelling agent.
Pathogen – One of a class of virulent micro organisms or bacteria found in the tissues
and fluids in infectious diseases and supposed to be the cause of the disease.
Photolytic (photolysis) – The breakdown of molecules into smaller units via
absorption of light.
Pigment – Solids in powdered form, which are derived from chemical reactions,
minerals, vegetables or animals. Pigments may be organic or inorganic. Pigments give
a paint film its colour and opacity (hiding power), but may also improve the paint
film’s hardness and durability.
Polymer – A naturally occurring or synthetic medium consisting of large molecules
made up of a series of repeated simple monomers.
Prokaryotic – Essentially a simple type of cell, lacking organelles (persistent structure
with specialized function).
Protista – A group (kingdom) including all organisms of simple biological
organization, such as algae, bacteria, fungi and protozoa.
Protoplasm – The living substance of the cell including cytoplasm and nucleus.
Qualitative – Involving distinctions made on quality.
Quantitative – Involving distinctions based on quantity.
Resin – The binder or film forming constituent of the paint. It is the adhesive that
holds the pigment and other additives together. The resin contributes mainly to the
durability, provides the necessary mechanical and physical properties and provides
the adhesion, cohesion and flexibility of the coating.
Solvent – A liquid substance capable of dissolving other substances that does not
change its state in forming a solution. Water is the solvent for the Biosan range of
products.
Superbugs – A colloquial term applied to certain strains of bacteria that have
developed resistance to some antibiotics; eg; MRSA.
Virus – An ultramicroscopic infectious agent that replicates itself only within cells of
living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in
a thin coat of protein.
Yeast – A single celled organism that can cause infection. Many types are of great
economic importance in brewing and baking. They can also be a source of proteins
and vitamins.