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The present invention relates to a system for suspending microbes or other analytes to allow the determination of the microbiological safety or hygienic quality of foods and other samples or to mix powders and/or liquids.

In order to determine the existence and quantity of microbes or other analytes in foods and clinical samples it is usual to remove them from the sample and disperse them in an appropriate liquid medium. It is desirable for the resulting suspension to contain minimal debris as such debris can interfere with the analysis.

Apparatus for suspending target microbes or analytes in a liquid without generating debris is described in EP0912237. This apparatus utilises shock waves generated by alternately beating either side of a plastic bag containing a sample and a liquid. The beating action is provided by a vibrating or reciprocating beater which is operated at a frequency sufficient to ensure that the plastic bag is able to only partially follow the movements of the beater. The Shockwaves caused by the beating action have a suspensive effect and, in the circumstances where the bag is in permanent contact with the beater on both sides of the bag, also provide a mixing action within the bag.

EP0912237 further describes releasable sealing means for confining a test sample with suspending liquid in a plastic bag, and transmission of energy to said sample and suspending liquid by means of non-crushing impacts on the outside of the bag, said impacts being within a range of frequency and amplitude such that they produce a suspending energy composed of a combination of shock or sound waves and mechanical shaking. To achieve this the sample and suspending liquid is releasably sealed in a flexible bag so that the bag hangs freely with some air space above the liquid. The bag is then beaten by a vibrating or reciprocating beater which beats the bag on alternate sides at a frequency high enough that the bag is only able to partially follow the movements of the beater thus producing an action in which:

(1) Shock waves caused by impact of the beater with the bag have a suspending effect;

(2) impulses imparted to the liquid during the pat of each cycle when the beater is in continuous contact with the bag produce a strong stirring action in the sample and suspending liquid which assists the suspending movement of liquid and by agitating the sample also improves the suspending effect; and

(3) no backing plate is required in order to produce the desired suspending action.

The suspended target analytes or microbes are tested through an appropriate testing regime. For example, one suitable method of analysis is immunomagnetic separation. This process comprises introducing specifically prepared immunomagnetic beads into a suspension in order to bind targeted biomolecules to the beads. The beads are then collected and tested for the presence of the targeted biomolecules. Different beads are used depending on the target biomolecule and testing parameters.

US2010/144005 describes processes and apparatus for selectively isolating microorganisms from a sample. A sample is provided in a container filled with a medium for enriching microorganisms in the container. Magnetic particles are then added to the container. The magnetic particles are selected based on their ability to bind to a target microorganism. The container is then vibrated to aid the binding of microorganism to the magnetic particles before collection from the bottom of the container by way of a magnetically assisted pipette.

The present invention seeks to provide improvements to the prior art.

An aspect of the invention provides a system for automated sample preparation comprising a vibrating beater for beatingly engaging a sample container alternately on opposite faces thereof in a first direction and sample manipulation means for delivering the sample to the vibrating beater in a second direction different to the first direction.

The sample may be any suitable sample which requires testing. For example, the sample may be a food sample, and environmental sample or a sample taken with a swab or similar collection device. The food sample may be any human or animal foodstuff, including livestock fodder. The environmental sample may be taken from any suitable source, including but not limited to soil, manure and livestock bedding. It is preferred that the sample is a food sample,

The sample may contain microbes and/or analytes which it is desired to detect or determine. Microbes may be any suitable microbe, including bacteria, viruses, fungi, archea or protists. The analyte may be a chemical component of the sample or a contamination thereof. The analyte may be organic or inorganic.

The apparatus in EP0912237 requires manual intervention to place a plastic bag in the vibrating beater and again to remove the plastic bag from the vibrating beater. The present invention enables a sample container to be moved automatically into the vibrating beater along a direction of travel that is different to the direction of movement of the vibrating beater. Automated sample entry and exit speeds up the sample preparation process as an operator can load multiple sample containers on to the apparatus at one time and allow the process to run with minimal supervision. Furthermore, an automated process minimises the risk of damage to the sample container and the sample contained therein being rendered unusable.

A configuration in which the second direction, i.e. the direction in which the sample container enters the vibrating beater, is perpendicular to the first direction, i.e, the direction in which the vibrating beater moves, is advantageous to optimise ease of entry to and exit from of the sample container into and out of the vibrating beater respectively.

The vibrating beater may comprise a pair of spaced apart parallel bars defining a channel therebetween configured to receive a sample preparation container.

The spacing between the parallel bars may be adjustable.

The spacing between the parallel bars is set to ensure that when the vibrating beater is operated the sample container can only partially follow the movement path of the vibrating beater. To provide greater functionality of the claimed invention, adjustability of the spacing between the parallel bars enables an operator to use more than one size of sample container. This is important as different testing techniques require different sample sizes and in some cases different sample containers.

The vibrating beater may further comprise a sample container inlet and a sample container outlet, wherein the sample container inlet and/or sample container outlet each define a respective funnel to facilitate entry to and/or exit from the vibrating beater by the sample container.

The provision of a funnel at the entrance to and exit from the vibrating beater reduces the risk of the sample container snagging on the vibrating beater and the sample therein becoming unusable due to potential damage to the sample container.

A sealing means may be provided for sealing the sample container as said sample container is beatingly engaged by the vibrating beater.

The sealing means may comprise one or more bars or pads moveable between a first position in which a space is defined between the sample container and the vibrating beater and a second position in which the bars or pads engage the sample container and the vibrating beater.

Provision of a sealing means that is operable to seal the sample container only when the sample container is positioned within the vibrating beater provides an effective means of sealing the sample container while minimising the risk of tearing the sample container during entry to and exit from the vibrating beater.

The sample manipulation means may comprise a track or conveyor having sample container engaging portions for engaging the sample container.

Use of a track or conveyor enables each sample container to follow a defined path through multiple process steps from sample container preparation to filling with a sample, weighing, filling the sample container with diluent, suspension and sampling, for example.

The sample manipulation means may comprise multiple tracks or conveyors, each defining a respective path. Each respective path may incorporate a respective vibrating beater.

The use of multiple tracks or conveyors with a respective vibrating beater per defined path permits scalability of the system to prepare multiple samples at the same time. It is also possible for each path to be associated with a common vibrating beater.

Another aspect of the invention provides a sample container for immunomagnetic bead separation comprising a container having a base, a sidewall and a removable or openable top, wherein the base has a channel or receptacle for collecting immunomagnetic beads and the sidewall defines a continuous convex or concave internal surface.

The convex or concave internal surface of the side wall acts in the same manner as the bars of the previously discussed aspect of the invention. The sample container claimed enables the downstream testing of the prepared system that would otherwise not be possible using prior art sample containers.

The continuous convex or concave internal surface of the side wall may be provided by a removable insert.

Use of a removable insert enables the sample container to be re-used following autoclave sterilisation with only the insert being disposable.

The invention will now be described by way of reference to the following figures:

Figure 1 illustrates a schematic of a system according to the present invention;

Figure 2 illustrates a sample container according to an embodiment of the invention.

The system (10), as illustrated schematically in figure 1 , comprises a vibrating beater (12) defined by a pair of spaced apart parallel bars (14, 16). Each bar (14, 16) has a flared end to facilitate introduction of a sample container (18), i.e. a re-sealable bag as known in the art, into the vibrating beater (12). The distance between the bars (14, 16) is dependent on the sample container used. The bars (14, 16) are connected to an electric motor (not shown), or other drive means, such that when the electric motor is switched on the bars vibrate in a frequency range of between 2,900 cycles per minute at an amplitude of 12-20 mm and 5,000 cycles per minute at an amplitude of 5-10 mm. In one embodiment, the electric motor is operably coupled to the bars (14, 16) by way of a crank but other power sources are not excluded.

The spacing between the bars (14, 16) can be adjusted manually be an operator or automatically using an electrical, pneumatic or hydraulic drive means for example to permit different sized sample containers to be used in conjunction with the system (10).

The vibrating beater (12) can be enclosed within a casing to prevent environmental contamination of sample container content. Such a casing is provided with an entrance and an exit through which the sample container passes as it enters and exits the vibrating beater (12) respectively. A window is provided in the casing to enable an operator to look into the vibrating beater (12) and ensure that no spillage has occurred without risking splashing of sample container (18) content onto the operator. The casing also comprises a door to enable access into the vibrating beater (12). Furthermore, a tray is positioned underneath the bars (14, 16) to contain any spillage caused during the vibrating, or pulsifying, process.

To remove particles from the resulting suspension, the sample container (18) may comprise a filtration region (not shown) configured to remove particles of a certain size.

The sample container (18) is, in use, suspended from a hook or frame attached to a track or conveyer type manipulation means that incorporates a bag sealing mechanism, as described below (20). The track or conveyer (22) may define a continuous loop or a start point and an end point. The sample container (18) is filled with a sample of food either manually or by way of an automated sample dosing device. Once filled, the sample container (18) is weighed deducting the tare weight of the sample container (18) to accurately record the weight of the food therein. The weight of the food sample is used to calculate the amount of diluent required for the sample preparation process. The required amount of diluent is then added to the sample container (18) either manually or by way of an automated diluent dosing device. The type of diluent is selected either manually or automatically according to a pre-stored programme or following determination of the food sample type and weight.

Once the required amount and type of food sample and diluent are added to the sample container (18), the sample container (18) progresses around the track or conveyer until it reaches the vibrating beater (12). The sample container (18) is advanced into the vibrating beater at which point the sample container (18) is sealed.

the sample container (18) is sealed by the bag sealing mechanism (20), as illustrated in figure 2, which comprises a pair of separate bars or pads (24) suspended above the vibrating beater (12). As the sample container (18) approaches the vibrating beater (12) a space is defined between the vibrating beater (12) and the separate bars or pads (24). When the sample container (18) is positioned within the vibrating beater (12) the separate pads or bars (24) move downwards to trap the portion of the sample container (18) above the liquid content therein against the bars (14, 16) of the vibrating beater (12) while the beating is taking place. The bag is held stationary between the bars (14, 16) and the vibrating beater (12) is activated for a pre-determined time period (typically fifteen seconds but up to thirty seconds in circumstances where low microbe or analyte quantities are expected) such that the sample container (18) is vibrated in a direction perpendicular to the direction of travel of the sample container (18) as it moves through the vibrating beater (12). Following completion of beating the separate pads or bars (24) are moved upwards to release the sample container (24) and the sample container (18) is moved out of the vibrating beater (12) and at least partially opened to allow access by an operator or an automated sampling device. A sample of the resulting suspension is extracted from the sample container (18) and the sample container (18) is removed from the track or conveyor (22) for storage or testing.

In one embodiment the system (10) comprises multiple tracks or conveyors (22). Each track or conveyor (22) is configured to receive one or more sample containers (18). Each track or conveyor (22) is typically associated with a respective vibrating beater (12) to enable multiple samples to be prepared simultaneously but in certain circumstances it might be desirable to associate a common vibrating beater (12) with each track or conveyor (22).

An exemplary sample container (100) is shown in figure 3 comprising a base (102), a side wall (104) and a re-sealable top (106). The sample container (100) shown is cylindrical but it will appreciated that other geometries can be used. The inner surface of the side wall (104) defines a convex or concave circumference (108). The convex or concave circumference (108) can either be an integral part of the side wall (104) or provided by an insert that can be inserted into the sample container (100) through the top (106) thereof. The sample container (100) is made from a suitable plastic material such as PTFE.

The sample container (100) is, in use, placed on a vibrating plate to pulsify the content therein. As the plate vibrates in a frequency range of between 2,900 cycles per minute at an amplitude of 12-20 mm and 5,000 cycles per minute at an amplitude of 5-10 mm the content

of the rigid container (100) repeatedly impacts against the convex or concave side wall of the removable insert (102).

As with the embodiment described with reference to Figure 1 , the sample container (100) is movable on to the vibrating plate by a track or conveyor (22). No separate sealing means are required as the top (106) seals the sample container (100) after filling. The process described with reference to figure 1 is otherwise as applicable to the sample container (100).

The aforementioned description is provided by way of example only and should be used only as a method of interpreting the claims and is not intended to the limit the same in any way.