HYGIENE MONITORING APPARATUS, SYSTEM AND USES THEREOF

Abstract: The invention discloses a hygiene monitoring apparatus (2), a hygiene monitoring system and the uses thereof in a method for monitoring hygiene. The apparatus (2) comprises a measuring chamber (6) for a sample container (21). The sample container (21) contains a sample and at least a light emitting marker. There is a silicon photodiode (16) to measure the emission of the marker in the measuring chamber (6). The monitoring device (2) further comprises organs (24) for sending (A) and receiving (B) electronic information.

Description: HYGIENE MONITORING APPARATUS, SYSTEM AND USES THEREOF The present invention relates to a hygiene monitoring apparatus, system and uses thereof for monitoring hygiene. The apparatus measures the light output of a light- emitting marker used in a method for monitoring hygiene. The measuring apparatus according to the invention form advantageously together with the central unit a communications network, with the aid of which network the hygiene monitoring can be arranged. Hygiene may be monitored with methods for determining the number, or presence of living microorganisms in the target to be monitored by using different sampling and sample cultivation techniques. It is also known to use methods, wherein the number of living microbes is measured indirectly by determining the amount of markers, such as adenosine triphosphate (ATP), which are characteristic to life. ATP is commonly determined with methods based on biolummescence, wherein ATP makes a bioluminescent marker emit light which is measured. According to Hazard Analysis of Critical Control Points (HACCP) in use today the system has to be fast and efficent so that problem situations can be addressed immediately. The measuring apparatus and system used for monitoring hygiene should be easy to use and enable fast interpretation of results. To measure bioluminescence, relatively expensive laboratory instruments based on photomultipliers are used, thus limiting the wide-spread application of the method for determining hygiene. For this reason, methods based on bioluminescence have hitherto been unsuitable for applications requiring simple, truly portable, low-cost equipment, which is independent of mains current, and resists field conditions. Portable equipments based on photomultipliers have of course been developed, but due to the technique applied, they are relatively expensive and thus unsuitable for wide-spread use. The patent EP 439 525 discloses a portable apparatus, wherein the measurement of light is based on an avalanche photodiode (APD). Accord- ingly, a more advantageous alternative to the solutions using photomultipliers is provided. This avalanche photodiode technique requires the use of rather high voltages, and cooling is also necessary for utilising special features thereof, and thus the solutions based on this technique are neither simple nor low-cost. The patent publication GB 2 001 434 presents the use of a photodiode for quantifying somatic cells from milk in order to determine mastitis. In such a case there is plenty of ATP in the sample, and no sufficient sensitivity or ease of use is achieved with the present method for monitoring hygiene. The measuring comprises for ex- ample the cumbersome pipetting stage and manual zeroing of the measuring apparatus. GB 2 001 434 does not also present an automatic processing of the measurement information or transferring of information between the measuring apparatus and a separate information processing device. The publication WO 98/49544 presents a measuring apparatus using a photomulti- plier, which comprises the required characteristics for sending the measurement results, however, possibility of a two-way communication between the measuring apparatus and the central unit is not intended here. For instance, manipulation of the action limits via the data communication network is not disclosed in the publi- cation. GB 2 178 847 presents a measuring apparatus using a photomultiplier, which apparatus measures the level of hygiene directly on the surface of the object to be measured. All substantial objects in hygiene monitoring, for instance taps or noz- zles, are not well suited for such a method. Furthermore, there are no properties for transferring data in the measuring apparatus presented in the publication. The object of the invention is to provide a hygiene monitoring apparatus that is simple and thus compact, pocket-sixed or otherwise easily portable, independent of mains current, resistant to field conditions and inexpensive. The object of the invention is further to provide a hygiene monitoring system, which enables efficient maintenance of HACCP. According to the invention, this object may be attained by using a silicon photodiode for measuring light. Silicon photodiode is much less sensitive than a photomultiplier and even clearly less sensitive than an avalanche photodiode, but it is, however, adequate for hygiene assays. In hygiene assays, an adequate sensitivity means a sensitivity sufficient to detect a contamination indicating a substantial health risk. The apparatus may be constructed to be very compact and inexpensive by using a common silicon photodiode, which is very low-cost compared to a photomultiplier and inexpensive even compared to an avalanche photodiode. As a power source, any ordinary optionally rechargeable finger-like battery may be used, and no elements used in prior art solutions based on a photomultiplier or an avalanche photodiode for generating high power or cooling are needed. In the solution according to the invention, there is no separate cooling element to lower the operation temperature of the light detector in contrast to present apparatuses designed for more sensitive and precise measurements, that is, the apparatus of the invention is not cooled. The idea of the invention is that even with such straightforward apparatuses, adequate sensitivity for purposes of monitoring hygiene is attained. If only a qualitative result is desired by applying the invention, a rather low signal to noise ratio may be satisfactory, whereas a quantitative result requires a higher signal to noise ratio, but even in this case, the measuring accuracy being few percent, a sensitivity sufficient for hygiene monitoring purposes may be attained with the solution of the invention. At present it is thought that for a qualitative result, the signal should be a few times, for instance 3 - 5 times stronger than the noise, and for a quantitative result, the signal should be clearly, e.g. 10 - 30 times stronger than the noise, but this necessary ratio is influenced by several factors including the characteristics of the noise and the ability to eventually process the signal from the silicon photodiode by computation. The apparatus and system according to the invention enables a powerful and inexpensive method for monitoring hygiene to be used for hygiene monitoring purposes, which may not be satisfied with techniques of prior art since the application of known technique requires expensive instruments and/or expertise. For instance cleaning service providers, restaurants including fast food restaurants, and various locations in food industry have such needs. A measuring apparatus according to the invention is easily made pocket-sized, nonetheless the apparatus may comprise the means necessary for information processing and/or information transferring, such as memory, microprocessor and the technology enabling the data transfer. With the aid of the necessary software information can advantageously be transferred from the measuring apparatus to an external central monitoring unit as well as from the central unit to the measuring apparatus. Data may be transferred between the measuring apparatus and central unit via a mechanical interface or with the aid of communication electronics without a mechanical interface. For example measurement results can be sent from a hand-held measuring apparatus to an external central unit or the like for processing. The central unit can send to the measuring apparatus according to the HACCP-monitoring program for example the alarm limit values of each respective object to be measured and information for necessary measurement objects. One central unit can be in contact with several measuring apparatuses. The hygiene monitoring apparatuses may thus function as remote terminals for different hygiene measurement points, for instance in production lines for the food industry, from which hygiene monitoring apparatuses the results of the hygiene determination can further be dispatched and to which apparatuses information can be sent. According to what has been presented above the measuring apparatuses form a hygiene monitoring system which enables efficient maintenance of self- monitoring. More precisely, the characteristic features of the hygiene monitoring apparatus ac- cording to the invention and the method using it are presented in the characterising parts of the enclosed independent claims. In this connection, a silicon photodiode refers to a photodiode, wherein the light sensitive material of the active area thereof is silicon, the bias voltage used being lower than IO N. The invention will now be described in more detail by referring to the appended drawings in which: Figure 1 shows the principle of a hygiene monitoring apparatus as a longitudinal section. Figure 2 shows an explosion view of a light detector of a hygiene monitoring apparatus as seen from the upper end of the apparatus. Figure 3 shows a schematic view of a swab for taking a hygiene sample and sample container, as well as, data transfer between the central unit and measuring apparatuses according to the invention. The hygiene monitoring apparatus 2 according to the embodiment shown in figures 1 and 2 comprises a body 4, a measuring chamber 6 for a sample container, a light detector 8, a circuit board 10 and a power source casing 12. The body is primarily sized according to the size of a sample tube, so that the size of the sample tube determines the size of the measuring chamber 6, this measuring chamber in turn de- termining the total length of the apparatus, and for the most part the depth thereof. In this embodiment, the outer dimensions of the hygiene monitoring apparatus are about 180 mm (length) x 60 mm (width) x 30 mm (depth). The weight thereof is about 300 - 400 g. The dimensions of the apparatus 2 may of course be significantly reduced, if the sample container used is significantly smaller than the sam- pie tube, for which this embodiment is designed. The light detector 8 is placed at the lower end of the measuring chamber 6. The heart of this hygiene monitoring apparatus 2 is the circuit board 14 of the light detector 8, the circuit board being enclosed in an aluminium housing 15 or like, that protects it against environmental influences. To this circuit board 14 of the light detector, a preamplifier is placed as a surface mounting component. Also a photodiode 16 with an active area of a size of 5.8 x 5.8 mm for this embodiment is fixed on this same circuit board. The housing 15 both acts as an electromagnetic shield around this sensitive electronic preamplifier, and forms a part of the mechanics of the apparatus for placing the sample tube in front of the photodiode 16 and for immobilising it during the measurement. The components in the housing 15 are connected to the other electronic components through an interface 18 on the side of the housing 15. If desired, it is also possible to use conductors soldered on the preamplifier card 14, the free ends of which may be soldered directly onto the circuit board 8 of the other electronic components. The apparatus of this embodiment is designed to be battery-powered wherein a finger-like battery may be replaced with a corresponding rechargeable battery. The apparatus may also be provided with a mains transformer or a cigarette lighter connection. The minimum operating time with a rechargeable battery is estimated to be eight hours. The apparatus of this embodiment is designed for bioluminometric measurements of ATP concentrations of contaminants. In this case, the measuring is conducted on wavelengths from 400 to 600 nm, approximately 562 nm, being the wavelength of the firefly luciferase emission. A schematic view of one hygiene monitoring system according to the invention is shown in figure 3, which system comprises as an example three measuring apparatuses 2 and a central monitoring unit 22. The hygiene sample is taken with swab 20, which is pushed into the sample tube 21. The measuring chamber 6 of the measuring apparatus 2 (see figures 1 and 2) is adjusted for the sample tube 21 tailored for monitoring hygiene, which sample tube 21 comprises the reagents re- quired by the method. The sample is taken for instance by brushing the swab 20 against the surface where hygiene is to be measured. Sample tube 21 and swab 20 may be as presented in patent publication WO 95/07457. The reagents contained in sample tube 21 are advantageously arranged in separate compartments, separated for instance by thin membrane. In this case the reagents are mixed only when the swab 20 containing the sample are pushed into the sample tube 21 thus breaking the membranes. The apparatus 2 may be provided with an indicator light display and/or a numeric display. The indicator light display may consist of LED indicators wherein each indicator lamp lit up corresponds to measurement values below or above predetermined limiting values. It may for instance consist of green, and red LED indicators, wherein an acceptable result lights up the green LED, and correspondingly, an unacceptable result lights up the red LED. The apparatus 2 may further be provided with a memory for storing, say, the last 1000 measurements. The data to be stored may for instance be: measuring time, the number of the sample, the name of the sample, and resulting value. The apparatus 2 may be designed and constructed with an optional connection to an external equipment 22, for instance to a computer for entering and/or altering the set values used and sample data, and for transmitting the obtained results to desired locations, for instance to result data bases, for eventual processing and/or reporting. The measuring apparatuses presented in figure 3 comprise a communication device 24 based on electronic communications, through which device the measuring apparatuses can be in contact with the communication device 23 of the central unit 22. The communications may work in a two-way manner: from the measuring apparatus to the central unit, which is indicated by arrow A, or in the opposite direction, which is indicated by arrow B. The central unit 22 may send for instance changed set values of the hygiene determination or the like according to the self -monitoring program to the measuring apparatus, to which values the object to be measured should adhere. The software of the central unit 22 can, for instance, advise the measuring apparatus 2 to slow down or speed up the sampling on the basis of the information coming from the measuring apparatus. Such communication may be wireless or be based on a leased line. The operations of the apparatus may be programmed to be as simple as possible, so that any person may use it in any place after minimal training. For instance, the start of the measurement may be coupled to the enclosure of the sample in the sample chamber. The measurement result may be automatically sent and received from the hygiene monitoring apparatus to the central unit and in the opposite direc- tion. It is evident for those skilled in the art, that the invention is not limited to the above description, but may vary within the scope defined in the appended claims. It is further evident, that all examples of embodiments described above and in the claims, which apply to the monitoring apparatus as such also apply to the system which comprises the monitoring apparatus. The hygiene monitoring apparatus and hygiene monitoring system may be realised without the two-way communication described above as well. It is also known to use a phototransistor as light detector.

Claims: Claims 1. A hygiene monitoring apparatus (2), comprising a measuring chamber (6) for a sample container (21), which sample container contains at least a light emitting marker and a sample to be measured, preferably a swab (20) for taking a hygiene sample, and which measuring chamber (6) contains a light detector (8) for measuring the emission of the marker, characterised in that the light detector (8) is a silicon photodiode (16) and that the monitoring apparatus (2) further comprises organs (24) for sending (A) and receiving (B) electronic information. 2. A hygiene monitoring apparatus (2) as claimed in claim 1, characterised in that the light detecting photodiode (16) is uncooled. 3. A hygiene monitoring apparatus (2) as claimed in claim 1 or 2, characterised in that a wall of the measuring chamber (6) comprises an opening, through which the light is adjusted to be emitted to the silicon photodiode (16), and another opening, through which the sample container (21) containing the sample is adjusted to be placed into the measuring chamber (6) in measuring position wherein the sample container (21) is adjusted to be contained light-tight in the monitoring apparatus (2) for the measurement. 4. A hygiene monitoring apparatus (2) as claimed in claim 1, 2 or 3, characterised in that the monitoring apparatus (2) comprises a circuit board (8, 12) for a preamplifier, for the silicon photodiode (16) and for any other components such as a memory, a display and a computer interface, necessary or favourable for the operation of the apparatus. 5. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that the power source of the monitoring apparatus (2) is a direct current source, preferably an optionally rechargeable battery. 6. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that the apparatus (2) is adjusted to measure light with wavelength from 400 to 600 nm, preferably 562 nm, being the wavelength of the firefly luciferase emission. 7. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that the organs (24) for sending (A) and receiving (B) the electronic information enable wireless data transfer. 8. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that the monitoring apparatus is adjusted to start the measuring of the sample when the sample is closed in the measuring chamber (6) in measurement position. 9. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that the result of the measurement is adjusted to be indicated with indicator lamps, preferably with 2 or 3 indicator lamps, wherein each indicator lamp burning is adjusted to correspond to measurement values below or above predetermined limiting values. 10. A hygiene monitoring apparatus (2) as claimed in claim 8, characterised in that the result is adjusted to be indicated with two indicator lamps, preferably with a red, and a green one, wherein the first indicator lamp, preferably the green one, is adjusted to indicate an acceptable result, and the second indicator lamp, preferably the red one, is adjusted to indicate an unacceptable result. 11. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that the monitoring apparatus (2) and/or the light detector ele- ment (8) thereof is enclosed in a metal housing, preferably an aluminium housing, to exclude interferences. 12. A hygiene monitoring apparatus (2) as claimed in any of the above claims, characterised in that it comprises a computer interface (18) and/or required electronics for data transfer and data reception for transferring the sample and measurement information and/or setting the set values of the apparatus. 13. A hygiene monitoring system comprising - a monitoring apparatus (2) as claimed in any of the claims 1-12, provided with a measuring chamber (6), - a sample container (21), which has been arranged to fit the measuring chamber (6), - a light emitting marker arranged in the sample container (21), and possible other reagents, which measuring chamber (6) has a light detector for measuring emission from the marker, characterised in that the light detector (8) is a photodiode (16). 14. A hygiene monitoring system as claimed in claim 13, characterised in that the system further comprises a central unit (22), which includes organs (23) for transmitting electronic information between one or more monitoring apparatuses (2) and central units. 15. The use of a monitoring apparatus (2) in a method for monitoring hygiene, wherein a) a hygiene sample is taken from the object to be examined with a swab (20) or the like, b) the sample is placed into a sample container (21), c) the sample container (21) is introduced into the measuring chamber (6) of the hygiene monitoring apparatus (2), and d) the sample is brought into contact with reagents necessary for the method already present in a sample container (21) or to be added therein in any of the steps a - c, which reagents make the sample emit light relative to the contaminants therein, characterised in that a hygiene monitoring apparatus (2) of any of the claims 1-12 is used in the method for measuring the emission of the marker to detect contaminations indicating a substantial health risk. 16. Use according to claim 15 to efficiently monitor hygiene in food industry ac- cording to the requirements of the HACCP. 17. Use according to claim 15 or 16, characterised in that the monitoring of hygiene is based on the bioluminometric determination of ATP contained in possible contaminants of the sample. 18. The use of a monitoring apparatus (2) in a method for monitoring hygiene, wherein a) a hygiene sample is taken from the object to be examined with a swab (20) or the like, b) the sample is placed into a sample container (21), c) the sample container (21) is introduced into the measuring chamber (6) of the hygiene monitoring apparatus (2), and d) the sample is brought into contact with reagents necessary for the method already present in a sample container (21) or to be added therein in any of the steps a - c, which reagents make the sample emit light relative to the contaminants therein, characterised in that a hygiene monitoring system of any of the claims 13-14 is used in the method for measuring the emission of the marker to detect contaminations indicating a substantial health risk.

Inventors: KAUNEELA MARKKU, KAUNEELA, MARKKU
Applicants: KAUNEELA MARKKU, RAPIDIAN KEHITYS OY, KAUNEELA, MARKKU
Application year: 2000
Main classification: G01N21
IPC codes: G01N21