Note: Descriptions are shown in the official language in which they were submitted.
WO90/14S91 2 o ~ 7 ~ o ~ PCT/DKgo/00123
Method for simultaneous control of cleaning and hygiene
and agent for use when carryis-g out the meth¢d
The present invention relates to a method for simultaneous
control of cleaning and hyg:iene, so-called prophylactic
cleaning, in particular for use in the food industry,
hospitals and other places where hygiene requirements are
high. The invention further relates to an agen-t for use
when carrying out the method.
Any production of food and any other processing or hand-
ling of materials containing oryanic matter of animal or
vegetable origin entail contamination of production rooms
and equipment.
It is desired to remove such contamination by daily
cleaning for the obvious reason that precisely this kind
of matter is fertile soil for the existence and growth
of bacteria, fungi and other microorganisms, the presence
of which is undesired because of their damaging influence
on the quality of the processed raw and finished products.
In the extreme case such microorganisms may be directly
hazardous to health.
The cleaning technology used today (irrespective of the
kind of cleaning performed) does not ensure complete
removal of the above organic contaminations for the simple
reason that many of such contaminations are difficult or
impossible to detect with the human eye. This is due
partly to their physical extension and partly to their
chemical nature.
Until now control of the hygiene on cleaned surfaces has
solely been performed by bacteriological methods, such as
culturing. Such mPthods for controlling the
WO 90/14~91 P~r/DK90/00123
2~s~no$ - 2
hygiene level are however inappropriate and often
inadequate, in particular for determining the quality of
the cleaning and controlling the hygiene level at places
where hygiene requirements are particularly high, e.g~
in the food industry, in hospitals and the like. The
bacteriological methods involve very significant dis-
advantages, of which in particular the following should be
mentioned:
1. Bacteriological methods can only be used for
determining live microorganisms (e.g. bacteria and
fungi), but not for determining the total amount of
organic contaminations which may give rise to
bacteria growth. This entails that by bacteriological
methods only the bacteriological hygiene state is
determined, whereas no impression of the overall
hygiene i~ obtained.
2. Bacteriological methods involv~ a considerable time
delay which in the extreme case may entail as much as
4 days insufficient bacteriological hygiene. E.g. in
slaughterhouses cleaning is performed in the evening
whan the day's production has been ended. The next
day (not earlier than 3-12 h after ended
disinfection) bacteriological samples are taken out
which then must be incubated for 24-72 h before the
resl~lt is available. Bacteriological methods for
control of hygiene are thus always delayed 1-4 days
relative to the time of sampling at the risk of
undetected dissatisfactory hygiene in the inter-
mediate period.
3. Bacteriological methods as an expression of the over-
all hygiene state further entail that inadequate
hygiene can be masked as a result of efficient
disinfection. This entails the risk that a build-up
WO90/14S91 2 ~ ~ 7 ~ ~ ~ PCT/DKgo/00l23
-- 3
of organic contaminations which have not been
measured or detected may give rise to growth of
microorganisms, in particular microorganisms of
resistant or pathogenic nature.
4. Finally, bacteriological methods are in practice only
usable as a sort of test sampling or spot check of
the hygiene, as samples or scrapes are taken at
selected places and compared with the total surfaceO
This involves a serious risk of "standardization",
meaning that the samples are constantly taken out at
the same places, which are thus currently checked
whereas the overall hygiene may be poor.
Consequently, there is a need for new methods with which
is is possible unambigously to determine the quality of
the cleaning during the cleaning process proper and
control the hygiene level immedialy upon completed
cleaning.
By the method according to the present invention there is
provided a surprisingly simple and reliable method capable
of fulfilling these objects.
2~ If an otherwise non-colouring cleaning agent contains a
dye or a combination of such dyes which react chemically
with organic matter - only organic matter of vegetable or
animal origin - and dyes the organic matter with a vislble
colour shade, such organic matter is made visible during
the cleaning process proper. Hereby organic contaminations
of any kind, including hard to see or even invisible
contaminations, are made visible and markedly
distinguishable form the background as such, whereby
places at which the required cleaning has been inadequate
are immediately revealed.
WO90/14S91 2 ~ 5 7 ~ Q 8 PCT/DK90/00123 -
-- 4 --
The invention thus relates to a method for simultaneous
control of clea~ing and hygiene, so-called prophylactic
cleaning, in particular for ~Ise in the foo~ industry and
hospitals, and the method of the present invention
is charac~erized in that an aqueous solution of a cleaning
agent containing a dye or a combination of such dyes which
bind on and colour organic matter of animal origin is
applied onto the surfaces to be cleaned when performing
the cleaning, whereby contamination, if any, of the
surfaces shows itself by colouring thereof.
In this way it is possible during the cleaning proper
objectively to determine the quality of the cleaning and
immediately control the level of hygiene. As a result
there is no risk - as was previously the case - that ths
cleaning is inadequate, and in addition there is no need
to wait as much as 4 days for the result of a
bacteriological control thereof which entailing risk of
contamination of intermediate production.
It is known that contami~ation of objects can be detected
by applying a substance yielding a coloured reaction with
the contamination. E.g. EP published patent application
No. 347494 discloses a method by which a dye solution
which is bound to the impurities is first applied onto the
object and secondly a developer solution. The contamina-
tion subsequently reveals itself in colour.
This is thus a two-step method which is used for
labeling of petroleum or silicone based contaminations,
such as coat1ngs on turbine blades.
US patent specification No. 4 745 797 discloses a method
of detecting leaks by which a dye solution is applied o~to
the object to be detected. The organic material, in
particular mineral oil fractions, seeping through the
2~7~8
WO90/145g1 PCT/DK90/00123
-- 5
leak will subsequently evoke a colour reaction and
consequently reveal the leak. The method is
particularly useful for leak control of fuel tanks in
aircrafts.
Such a dye method may aLso be used for revealing
unevenness or cracks in a surface, e.g. as disclosed in DE
public disclosure No. l 773 270. This is an indirect (not
immediately visible) colour reaction with specific
substances which call for detection with W -light in order
to be labeled.
It is a common feature of the methods disclosed in the
above specifications that they make use of dyes or
combinations of dyes for detection or visualization of a
physical state. However, none of the specificakions
concern utilization of a colour reaction for detecting
contaminated surfaces, removal of such contamination, and
~removal control in one and the same work cycle, as is the
case by prophyiactic cl~aning. By prophylactic cleaning is
understood a method which in conjunction with any kind of
cleaning process and any cleaning agent can visualize even
the tiniest occurrence of dirt during the cleaning process
proper.
In addition to a general increase in the hygiene standard
prophylactic cleaning involves a variety of apparent
advantages, o which in particular the following should be
mentioned:
l. Any person can - without special qualifications and
without using any kind of aids - quickly, in a simple
way and reliably evaluate the course and result of a
cleaning solely based on the presence or absence of
colour on the cleaned surface.
WO90/14591 PCT/DK90/00123
2~7~ 6 -
2. Any cleaning parameter, including choice of
agents, equipment and method can be evaluated
objectively during the cleaning proper. Hereby it is
made possible to optimize all cleaning parameters in
view of obtaining the desired hygiene at a minimum of
economical, environmental and human costs.
~he dye used in the method of the present invention may be
any dye or a speciic combination of such dyes which can
bind on organic materials of any animal and vegetable
kind, such as proteins, lipids and carbohydrates, and in
the process colour these materials if the dye is stable in
the selected combination with the cleaning agent.
A variety of dyes have this capability, and the invention
is thus not limited to any particular dye or any
particular cleaning agent. As the method of the invention
is extremely usable in slaughterhouses and other food
producing and processing industries it is in practice
preferred to use dyes which are already known - and
approved - in connection with food. Examples of food dyes
which are approved in the EEC-countries are Ponceau 4R
(El24), Carrnoisine (El22), Amaranth tEl23), Erythrosine BS
(El27), Ponceau 6R (El26) and Scarlet GN (El25), all of
which are red dyes. Yellow and orange dyes may be Orange
GGN (Elll), Tartrazine (El02), Sunset Yellow FCF (EllO),
Acid Yellow (El05), Quinoline Yellow (ElO4) and Chrysoine
S (El03). Green, blue, violet and black dyes are also
known, e.g. Brilliant Green BS (El42), Indigo Carmine
(El32), Patent Blue V (El31) and Black BN (El51).
Particularly preferred as dye for use in the method
according to the invention is Erythrosine BS (El27), a red
dye which is well-known for use in connection with
colouring of sausages. The substance which is marketed
by Pointing Ltd., Northhumberland, England, under the
WO90/14591 2 ~ ~ 7 0 ~) ~ PC~/DKgo/00l23
-- 7
trade name "Hexacol Erythrosine Supra" is the disodium
salt of the compound 2~4,5,7-tetraiodofluorescein, having
the formula
I O~c -~=I
~ COONa
~J
This dye is preferred because it is extremely well-suited
for the use. It thus reacts very quickly and has an
intensive colour effect. Further it exhibits negligent
toxicity, and it is already widely used in the food
industry and other are~s within which the present ~ethod
is usable.
Besides bein~ a well-known food dye, Erythrosine BS (El273
has been used within odontology, where it is
administered in tablets for control of toothbrushing, in
particular with children. Also here advantage is taken of
the marked colour effect and the negligent toxicity.
Finally, the substance has been used ophthalmologically in
connection with adaptation of contact lenses and
examination of eye diseases.
In the method according to the invention the selected dye
has been added to the concentrated cleaning agent, whereby
the dye is applied onto the surfaces during cleaning.
,~
The method according to the invention is applicable in
connection with all kinds of cleaning, such as foam
WO90/14591 ;2 ~ 5 7 ~ ~ 8 - 8 - PCT/DK90/00123
cleaning, manual cleaning, circulation cleaning, in
washing machines, when cleaning containers etc.
When using the preferred dye E127 preferably 1 g E127 per
kg cleaning agent is added. As the cleaning agent is
typically used in concentrations of 0.2-2,0~ (w/w), the
dye concentration used will be 2-20 mg per l end solution.
When the coloured cleaning solution has been applied
measuring or evaluation of the cleaning quality and the
hygiene standard can be performed in various ways: -
`:
1. Visual determination of the presence of colouredcoatings (which will be bright red if the preferred
dye E127 is used) can be performed.
2. Visual detexmination by use of fluorescen~ light can
be performed, some o~ the usabla dyes including E127
being flourescent.
3. Samples of the coloured surfaces can be taken out by
scraping and a chemical/technical measurement of the
dye concentration performed, e.g. spectrophotometric-
ally.
The advantages of the method according to the invention
are obvious because they allow daily evaluation of the
overall hygiene standard without time delay and extra
labour efforts. By the method there is performed no
conventional bacteria count but an overall evaluation of
the hygiene as regards bacteria and organic matter which
might give rise to growth of bacteria. Besides such a
daily control which is extremely important, the method
offers the possibility of teaching new staff correct
cleaning performance as the method easily reveals places
where cleaning is required or cleaning has been
~7~
WO90/14591 PCT/DK90/00123
g
dissatisfactory. Similarly, it is possible objectively to
control the part processes of which the cleaning consists,
such as mechanial processing, the efficiency of the
cleaning agent and the like. The method may also be used
to ensure that during flushing all traces of the cleaning
agent have been removed.
In the following the invention is illustrated in more
detail by way of an example.
EXAMPLE
At Den Danske Slagteriskole tThe Danish Meat Trade School)
in Roskilde experiments have been performed with
prophylactic cleaning by the method according to the
present invention. A common cleaning agent is used for the
cleaning in an end concentration of l.5-2~. The agent had
been admixed wi~h l g of the dye El~7 per kg cleaning
agent.
Cleaning was performed as ordinary foam cleaning with
K.E.W. standard foam equipm~nt ~temperature: approx. 40-
60C, pressure: 60-lO0 bar~. After cleaning no
disinfection was performed with chlorine or other
disinfectants.
The following results were obtained:
l. Cleaning generally
The prophylactic cleaning agent has optimal technical
efficiency:
- the product provides the desired foam formation and
foam stability.
WO90f14591 ~ ~ 7 ~ o - PCT/DK90/00123
- the product colours and makes visible all dirt
occurences in the course of approx. 5 min.
- the product loosens all occurring dirt types of both
oryanic and inorganic nature.
2. Hygiene
The prophylactic cleaning agent results in optimal
hygiene:
- according to visual determination all surfaces are
shining and clean after the cleaning.
- bacteriological measurements show a general hygiene
which is ~uite as good as the hygiene after
traditional cleaning with alkaline/acidic cleaning
agent and subsequent disinfection with chlcrine.
~. Working environment
The prophylactic cleaning agent causas none of the
traditional nuisances to the user:
- no eye, skin or respiratory irritations have been
observed, neither during the cleaning or in connection
with handlin~ the concentrated product.
By introducing prophylactic cleaning at the gut section of
the Meat Trade School, previously unseen control of both
the daily cleaning result and the user t S working
environment has been obtained. It should be noted that the
fine results have been obtained without changing cleaning
procedures and without increasing time consu~ption. On
the contrary, the cleaning as a whole has become
considerably easier due to the nature of the agent and the
WO gO/14591 2 ~ ~ 7 ~ 0 8 P~/DKgo/0()123
11
f act that the dirt is inade visible during the cleaning
proper .
~5
