GB2535568B

GB2535568B - Electrolyzed water composition

Info

Publication number: GB2535568B
Application number: GB1518472.4A
Authority: GB
Inventors: Philip Gardner Stephen
Original assignee: Ozo Innovations Ltd
Current assignee: Ozone Purification Ltd
Priority date: 2014-12-09
Filing date: 2015-10-19
Publication date: 2019-10-23
Anticipated expiration: 2035-10-19
Also published as: GB201518474D0; GB201518472D0; GB2535569A; GB2535569B; GB2535568A

Description

Electrolyzed Water Composition

Field of the Invention

The present invention relates to an electrolyzed water composition, an apparatus and a method for preparing an electrolyzed water composition, and the use of an electrolyzed water composition for reducing and/or eliminating food-borne pathogens on or in food products, such as for example on or in meat or poultry carcasses.

Background

Campylobacter contamination is known to be the most common cause of food poisoning in the UK, causing up to 280,000 serious food poisonings and up to 200 deaths in the UK every year. Campylobacter can be found in poultry, red meat, unpasteurised milk, and untreated water. ln particular, Campylobacter contamination of chicken is a major food safety problem. About four in tive cases of Campylobacter poisoning in the UK comes from contaminated poultry. Although Campylobacter does not normally grow in food, it is known to spread easily and has a low infective dose. As a result, illness can be caused by the presence of a few bactéria being transferred from uncooked food (such as for example chicken), to ready to eat foods. Campylobacter contamination has a significant impact on the UK economy and it is thought to cost the economy about £900 million a year. A survey of Campylobacter in chicken on retail sale was carried out in the UK between May 2007 and September 2008. The survey identified that Campylobacter was present in about 65% of the fresh chicken samples. More recent surveys in 2014 and 2015 have put the presence of Campylobacter in UK supermarket chickens at up to 80%. The surveys therefore highlighted that there are a number of Campylobacter-re\a[ed challenges in the current food safety system. One of the main priorities of the Food Standards Agency is to reduced food-borne diseases or pathogens, in particular Campylobacter in poultry carcasses.

There is a need for a food-safe, non-tainting composition for use within the food industry which has improved efficacy against food-borne pathogens. Standard electrolysed water Solutions containing hypochlorous acid cannot be used partly due to regulation limiting the amount of free accessible chlorine (FAC) in Solutions used in food contact applications to below 20ppm, a levei at which it is ineffective, and partly due to its noticeable chlorine smell. There is a need for a food-safe, non-tainting composition with improved efficacy against food-borne pathogens which has reduced associated cost implications and/or environmental implications.

Summary of the Invention

According to a first aspect of the present invention, there is provided a method for producing a substantially chlorine free electrolyzed water composition for use in reducing and/or eliminating food-borne pathogens on or in food substrates, the method comprising: preparing an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt and at least one alkali metal chloride salt, in which the total salt concentration of carbonate salt(s) and chloride salt(s) within the electrolyte solution is in the range of between 5 g/l and 50 g/l, and in which the ratio of the carbonate salt(s) to chloride salt(s) by weight within the electrolyte solution is in the range of between 0.6:1 to 1:1.2; introducing the aqueous electrolyte solution into an electrolytic cell comprising a plurality of boron-doped diamond electrodes; and operating a power supply to apply a predetermined voltage to the electrolyte solution within the electrolytic cell to produce an electrolyzed water composition comprising dissolved ozone (O3) having anti-microbial properties.

The electrolyte solution may be introduced into the electrolytic cell in a continuous or batch process manner.

Preferably the at least one chloride salt is sodium chloride or potassium chloride, or a combination thereof. More preferably, the at least one chloride salt is sodium chloride.

Preferably the at least one carbonate salt is anhydrous sodium carbonate or anhydrous potassium carbonate, or a combination thereof. More preferably, the at least one carbonate salt is anhydrous sodium carbonate.

For example, the aqueous electrolyte solution preferably comprises 56g sodium carbonate, 48g sodium chloride in 10 I water. Preferably, the total salt concentration of carbonate salts and chloride salts within the aqueous solution is in the range of 5.4 g/l and 15.6 g/l.

The ratio of carbonate salts to chloride salt(s) within the aqueous electrolyte solution is preferably greater than or equal to 1:1.

The electrolyte solution can optionally include one or more additional salts to enhance the anti-pathogenic properties of the resultant electrolyzed water composition against food borne pathogens.

The predetermined voltage is preferably in the range of between about 1 and 1000 volts DC, preferably in the range of between 48 to 96 volts DC.

The power supply preferably has a current in the range of between about 1 and 1000 ampere, preferably at about 24 ampere.

According to a second aspect, the present invention provides an electrolyzed water composition prepared from an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt and at least one alkali metal chloride salt, in which the total salt concentration of carbonate salt(s) and chloride salt(s) within the electrolyte solution is in the range of between 5 g/l and 50 g/l, and in which the ratio of the carbonate salt(s) to chloride salt(s) by weight within the electrolyte solution is in the range of between 0.6:1 to 1:1.2, in which the composition is substantially chlorine-free.

The electrolyzed water composition may comprise dissolved O3 in a concentration between about 0.1 and 1000 ppm, preferably between 1ppm and 750 ppm. The electrolyzed water composition preferably comprises dissolved O3 in a concentration between 10 and 500 ppm, more preferably in a concentration between 50 and 300 ppm.

The electrolyzed water composition is preferably substantially chlorine-free. The term “substantially chlorine-free” is used herein to refer to a composition comprising less than 20 ppm, preferably less than 5 ppm, more preferably less than 0.5 ppm FAC, even more preferably less than 0.1 ppm FAC, especially preferably less than 0.01 ppm FAC, for example 0 ppm FAC.

According to a further aspect, the present invention provides the use of an electrolyzed water composition as herein described for reducing and/or eliminating food-borne pathogens on or in a food substrate.

According to a further aspect, the present invention provides a method for reducing and/or eliminating food borne pathogens on and/or in a food substrate comprising applying an electrolyzed water composition as herein described to a food substrate.

The compositions of the present invention may be applied to the food substrate by any suitable means. The food substrate may, for example, be coated with or immersed within a tank or reservoir containing an electrolyzed water composition of the present invention. The electrolyzed water composition may be maintained at a predetermined temperature for receiving the food substrate. The efficacy of the electrolyzed water composition may be improved by maintaining the composition at a predetermined temperature. The time period over which the pathogen leveis are reduced (or eliminated) to an acceptable predetermined levei may be reduced by maintaining the electrolyzed water composition at a predetermined levei. For example, the electrolyzed water composition may be maintained at room temperature. Altematively, the electrolyzed water composition may be heated to a temperature of between about 40 °C and 50 °C.

The composition of the present invention may be applied as part of a treatment regime. For example, the composition of the present invention may be applied as a pre-treatment or a post-treatment before or after application of one or more conventional treatments, such as for example Sonosteam. The composition of the present invention may be applied concurrently with one or more conventional treatments.

The food substrate may be contacted with the electrolyzed water composition (for example immersed within a tank comprising the electrolyzed water composition) of the present invention for a predetermined period of time. For example, the food substrate may be contacted with or immersed within the electrolyzed water composition for at least 5 seconds, preferably at least 15 seconds, for example at least 20 seconds. The tank may receive a plurality of food substrates, either simultaneously or sequentially. The efficacy of the electrolyzed water composition may be improved by maintaining the composition at a predetermined levei of active species by continuai or periodic electrolysis.

According to a further aspect, the present invention provides an applicator for sanitizing equipment, in which the applicator comprises a reservoir comprising an electrolyzed water composition as herein described, and a nozzle in fluid communication with the reservoir. The applicator may comprise a reservoir which is arranged in use to be connected to a spraying device or to equipment for applying the electrolyzed water composition to the food substrate.

The applicator may for example be selected from one or more of: a nebuliser, a fogging mist applicator, a jet spray applicator, a spray applicator, or a wash system, or any combination thereof.

According to a further aspect, the present invention provides an apparatus for producing electrolyzed water composition for use in reducing and/or eliminating food borne pathogens on or in a food substrate, the apparatus comprising: a reservoir comprising an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt and at least one alkali metal chloride salt; an electrolytic cell in fluid communication with the reservoir to receive a feed stream comprising the aqueous electrolyte solution; and a plurality of boron-doped diamond located within the electrolytic cell and arranged in use to be connected to a power supply.

The electrolytic cell preferably comprises at least one outlet through which the electrolyzed water composition exits the electrolytic cell.

The system may further comprise one or more flow regulators arranged in use to adjust the flow of the electrolyte feed stream between the reservoir and the cell.

The system may further comprise a heater arranged in use to adjust the temperature of the flow of the electrolyte feed stream and/or the electrolyte solution within the cell.

The system may further comprise a control system arranged in use to control the flow rate of the electrolyte feed stream as required, such as for example by controlling the flow regulator(s).

The system may comprise a control system arranged in use to control the power supply to the electrodes.

The system may comprise a control system arranged in use to control the temperature of the electrolyte solution.

Control of the temperature of the electrolyte solution, the flow rate of the electrolyte solution feed stream, and the power supply to the electrodes may be provided by a single control system. Altematively, these factors may be controlled by separate control systems.

Brief description of Figures

Embodiments of the present invention will now be described by way of example, with reference to the following figures:

Figure 1 is a schematic representation showing the application of the electrolysed water solution as a dip or dunk for the in line disinfection of chicken carcasses.

Detailed Description

Example 1 - Electrolyzed water composition

An electrolyte solution comprising a total salt concentration of 10.4 g/l in water (5.6 g/l anhydrous sodium carbonate (Na2CO3) and 4.8 g/l sodium chloride (NaCI)) was prepared. The electrolyte solution is stored within a reservoir chamber in fluid communication with an electrolytic cell. A feed stream comprising the electrolyte solution was introduced into the electrolytic cell. The feed stream can optionally include one or more additional salts to enhance the antipathogenic properties of the resultant electrolyzed water composition. The electrolytic cell is a non-membrane electrolytic cell. The electrolytic cell comprises a casing, a plurality of boron doped diamond electrodes (BDEs) located within the cell, and metal ‘contact plates’ used for transmitting charge across the electrolyte solution.

The BDEs are sheet-like components and are provided in a stack of between 3 and 10 sheets. Each sheet is located at a fixed distance away from an adjacent sheet. The distance between adjacent sheets of BDEs provides a cell gap, which is preferably less than 5 mm, for example between approximately 2 and 3 mm. The BDEs are provided in a plastic frame. The BDEs transmit charge across the electrolyte solution, inducing a strong dipole and creating positively and negatively charged radicais on alternate surfaces of the diamonds.

The electrolyte solution may be introduced into the electrolytic cell in any suitable manner so as to produce electrolyzed water composition in a continuous process or in a batch process. In the continuous process, the electrolyte solution may be introduced at a suitable flow rate, such as for example at a flow rate in the range of from 0.1 to 100 l/min, for example in the range of from 3 to 5 l/min. ln the batch process, the electrolyte solution may have a flow rate of approximately 16 l/min. A power supply was operated to apply a voltage in the range of between 1 and 1000 Volt D.C. and a current within the range of from 1-1000 ampere to the electrolyte solution. The over-potential provided between the electrodes shifts the equilibrium within the electrolyte solution such that dissolved ozone is produced and remains within the electrolyzed water for a significant amount of time. For example, the half life of the dissolved ozone within the electrolyzed water composition is preferably at least a number of minutes, more preferably at least ten minutes, especially preferably at least 30 minutes, for example about 45 minutes.

The electrolytic cell preferably comprises an outlet through which the electrolyzed water composition exits the cell. The electrolyzed water composition preferably also has detergent properties. The electrolyzed water composition preferably comprises surfactant species.

The electrolyzed water composition according to this embodiment comprises dissolved ozone at a levei of approximately 300 ppm. This levei of dissolved ozone is approximately 100 times greater than the levei which can be achieved by injecting gaseous ozone into water. As a result, the electrolyzed water composition of the present invention has an increased anti-microbial efficacy compared to water which has been injected with gaseous ozone. The electrolyzed water composition may be used as an antipathogenic agent against food borne pathogens.

Although the electrolyzed water composition of the present invention contains dissolved ozone at a levei of approximately 300 ppm, it is to be understood that the electrolyzed water composition of the present invention may comprise any suitable levei of dissolved ozone, preferably within the range of between 0.1 and 10000 ppm, preferably between 1 and 1000 ppm.

Example 2

With reference to Tables 1 and 2, three groups of 30 poultry carcasses were treated with three different treatment methods.

Treatment 1: Untreated as a control sample;

Treatment 2: the Sonosteam process involving exposure to steam and ultrasound.

Treatment 3: the Sonosteam process followed by exposure to the electrolyzed water composition of Example 1. The Sonosteam treated poultry carcasses were immersed for 20 seconds per bird in a reservoir comprising the electrolyzed water composition of Example 1 as shown in Figure 1. The chicken carcass 2 is dunked into a bath 1 containing a circulating solution of the electrolyzed water composition of Example 1 3. The solution is circulated by means of a pump 5 which draws solution from through a pipe 4 from the end of the bath, filters it and passes it for re-electrolysis and heating in the BDE flow cell 6. The re-electrolysed solution is returned to the start of the bath by means of a pipe 7. The electrolyzed water composition of Example 1 was warmed to and maintained at a temperature between 40°C and 46°C.

The poultry carcasses of each group were then subjected to biopsy of the neck skin (a particularly difficult area to treat effectively) and breast skin (an easier part of the carcass to treat), with weighed skin samples being sent to a specialist testing lab to determine the levei of Campylobacter present (as colony forming units / gram of skin) at the day of kill (herein referred to as ‘DOK’) plus 4 days (Table 1); and again at the day of kill plus 7 days (Table 2).

Campylobacter levei at DOK plus 4 days Table 1

The average background contamination levei of Campylobacter after 4 days (DOK plus 4 days) was found to be 3+ log (ie. 1000 cfu/g). 35% of the group of the untreated control poultry carcasses were found, after four days, to have a levei of Campylobacter of greater than 1000 cfu/g. This levei of Campylobacter contamination is considered to be indicative of a heavily contaminated group of poultry.

Campylobacter \eve\ at DOK plus 7 days

Table 2

As shown in Tables 1 and 2, exposure of the carcass to the composition of Example 1 for a time period of 20 seconds per bird results in a reduction in the levei of Campylobacter of at least 1 log (90%). The levei of reduction may be further improved by prolonged exposure to the composition of Example 1. This significant reduction in the levei of Campylobacter furthermore results in a significant reduction in the number of human food poisonings as a result of eating contaminated poultry carcasses. This significant reduction in the levei of Campylobacter wou\d therefore have significant benefits and associated cost savings for food producers, such as for example poultry farmers, food processors, and retailers.

It can be seen from Tables 1 and 2 that the electrolyzed water compositions of the present invention achieves a significant reduction of at least 95% of Campylobacter pathogens on the poultry carcasses over a period of at least 7 days from the Day of Kill. Furthermore, the compositions of the present invention are effective in ensuring that no carcasses within the group have a Campylobacter levei of over 1000 cfu/g. The compositions of the present invention are therefore effective in reducing pathogen leveis on carcasses to be within safer limits and thereby significantly reducing the risk of food poisoning.

The compositions of the present invention have also been found to not provide any negative organoleptic results, such as for example poor taste or smell residues and/or visual or tactile degradation of carcass quality.

The present invention provides an electrolyzed water composition providing improved anti-pathogenic activity on or in food substrates. Although the present invention

demonstrates the effectiveness of the electrolyzed water composition with respect to reducing and/or Campylobacter on poultry carcasses, it is to be understood that the compositions of the present invention are effective against other pathogens, and in particular food borne pathogens, and are not limited to Campylobacter reduction and/or elimination. The compositions of the present invention are effective against a number of different pathogens on any suitable food substrate and are therefore not limited to reduction and/or eliminated of pathogens on or in poultry carcasses. The compositions of the present invention may be applied to the food substrate by any suitable method and/or for any suitable application time.

It is also to be understood that the electrolyzed water composition of the present invention may be applied at a higher dosage to the food substrate, and/or may reduce and/or eliminate food borne pathogens over a much shorter period of time than achieved for the low dosage application of the composition as shown in this Example.

Example 3

With reference to Tables 3 and 4, three groups of 30 poultry carcasses were treated with three different treatment methods.

Treatment 1: Untreated as a control sample;

Treatment 2: the Sonosteam process involving exposure to steam and ultrasound.

Treatment 3: exposure to the electrolyzed water composition of Example 1. The poultry carcasses were immersed for 15 seconds per bird in a reservoir comprising the electrolyzed water composition of Example 1. The electrolyzed water composition of Example 1 was warmed to and maintained at a temperature between 43°C and 50°C.

The poultry carcasses of each group were then subjected to biopsy of the neck skin and breast skin, with weighed skin samples being sent to a specialist testing lab to determine the levei of Campylobacter present at day of kill plus 4 days (Table 3).

Campylobacter levei at DOK plus 4 days Table 3

The average background contamination levei of Campylobacter after 4 days (DOK plus 4 days) was found to be 2+ log (ie. 100 cfu/g). 7% of the group of the untreated control poultry carcasses were found, after four days, to have a levei of Campylobacter of greater than 1000 cfu/g. This levei of Campylobacter contamination is considered to be indicative of an unusually lowly contaminated group of poultry, and smaller levei of reductions following treatment are expected when the starting population of Campylobacter is lower.

Although the Examples illustrate the effectiveness of the electrolyzed water compositions of the present invention within poultry processing environments, it is to be understood that the compositions, method and apparatus of the present invention can be used to reduce and/or eliminate food borne pathogens in any suitable environment, and is not to be limited to poultry processing environments.

Claims

1. A method for producing a substantially chlorine free electrolyzed water composition for use in reducing and/or eliminating food-borne pathogens on or in food substrates, the method comprising: preparing an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt and at least one alkali metal chloride salt, in which the total salt concentration of carbonate salt(s) and chloride salt(s) within the electrolyte solution is in the range of between 5 g/l and 50 g/l, and in which the ratio of the carbonate salt(s) to chloride salt(s) by weight within the electrolyte solution is in the range of between 0.6:1 to 1:1.2; introducing the aqueous electrolyte solution into an electrolytic cell comprising a plurality of boron-doped diamond electrodes; and operating a power supply to apply a predetermined voltage to the electrolyte solution within the electrolytic cell to produce an electrolyzed water composition comprising dissolved ozone (O3) having anti-microbialproperties.

2. A method as claimed in claim 1, in which the electrolyte solution is introduced into the electrolytic cell in a continuous or batch process manner.

3. A method as claimed in any preceding claim, in which the predetermined voltage is in the range of between 1 and 1000 volts DC.

4. A method as claimed in claim 3, in which the power supply has a current in the range of between 1 and 1000 ampere.

5. An apparatus for producing a substantially chlorine free electrolyzed water composition for use in reducing and/or eliminating food borne pathogens on or in a food substrate, the apparatus comprising: a reservoir comprising an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt and at least one alkali metal chloride salt, , in which the total salt concentration of carbonate salt(s) and chloride salt(s) within the electrolyte solution is in the range of between 5 g/l and 50 g/l, and in which the ratio of the carbonate salt(s) to chloride salt(s) by weight within the electrolyte solution is in the range of between 0.6:1 to 1:1.2; an electrolytic cell in fluid communication with the reservoir to receive a feed stream comprising the aqueous electrolyte solution; and a plurality of boron-doped diamond located within the electrolytic cell and arranged in use to be connected to a power supply.

6. An electrolyzed water composition prepared from an electrolyte solution comprising water, at least one anhydrous alkali metal carbonate salt and at least one alkali metal chloride salt, in which the total salt concentration of carbonate salt(s) and chloride salt(s) within the electrolyte solution is in the range of between 5 g/l and 50 g/l, and in which the ratio of the carbonate salt(s) to chloride salt(s) by weight within the electrolyte solution is in the range of between 0.6:1 to 1:1.2, in which the composition is substantially chlorine-free.

7. An electrolyzed water composition as claimed in claim 6, in which the electrolyzed water composition comprises O3 in a concentration between 0.1 and 1000 ppm.

8. An electrolyzed water composition as claimed in claim 7, in which the O3 concentration is in the range of 1 to 1000 ppm.

9. Use of an electrolyzed water composition as claimed in any one of claims 6 to 8 for reducing and/or eliminating food borne pathogens on or in a food substrate.

10. A method for reducing and/or eliminating food borne pathogens on and/or in a food substrate comprising applying an electrolyzed water composition as claimed in any one of claims 6 to 8 to a food substrate.