The facts behind the unique sanitising capability of GUARDIAN


Kills airborne bacteria.

Reduces the spread of MRSA, c.difficile, and other airborne bacteria.

Removes odours.

How it works

An easy, safe way of removing unpleasant odours, using all natural ingredients to neutralise airborne bacteria and generate a pleasant aroma by dispensing natural anti-bacterial essential oils into the environment.

Guardian has been used in Care Homes and Hospitals throughout the country to control the spread of MRSA, c difficile, Aspergillus Niger and other airborne bacteria. Guardian liquid works efficiently to reduce the spread of bacterial spores that hang around in the air and on surfaces.

Guardian liquid is converted into dry sub-micron particles via a diffuser unit, these units can cover areas from small offices to large commercial areas and also via air conditioning systems. As the particles are of a sub-micron size they can remain suspended in the air for longer periods providing greater beneficial effect, allowing them to come into contact with more germs and airborne bacteria.

The breakdown of oils in this unique manner is not effective in candles, bulb rings and other heat units and therefore does not have the same effect.

When the sub-micron particles are in the air contact reduces levels of infectious pathogens, fungus, and moulds whilst removing malodour and leaving a pleasant aroma.

The Safer Air system and Guardian oil eliminates airborne bacteria that creates odour, and reduces surface bacteria that spread infections.

Trials run at 50 care homes before and after

2 weeks

*tests conducted by Smith and Nephew

Trial objective:

To incubate and count a set of 45 plates provided from environmental sampling. Colonies on plates to be presumptively identified based on colony morphology and use of diagnostic media.

Materials & Methods:

Plates were delivered to the research centre by Marcel Leader after he carried out sampling at test locations. All plates except Clostridium difficile specific agar were incubated at 32°C for at least 72 hours prior to counting. Clostridium difficile specific agar plates were incubated at 37°C in an anaerobe cabinet for at least 72 hours prior to counting.

A basic presumptive identification of colonies was carried out in addition to colony counting based on morphology, and in the case of MRSA and Closiridium difficile specific agars based on the diagnostic characteristics of these species on these media.

Tests performed by Smith and Nephew Technical Services Group

Test no. EXTOO -08-0 fi0

Trial conducted at Burns unit at Wythenshawe Hospital

The use of essential oil vapours to eradicate airborne bacteria.

Full study carried out by:
Prof. Valerie Edwards-Jones MMU
Dr. Anna Doran MMU
In collaboration with:
Dr. Ken Dunn, Wythenshawe Hospital

The number of antibiotic resistant bacteria continues to grow, despite the best efforts of our healthcare professionals. Methicillin-resistant Staphylococcus aureus (MRSA) makes the headlines most often, but there are others that are equally problematic.

Working in collaboration with Prof. Valerie Edwards-Jones and Dr Anna Doran at Manchester Metropolitan University (MMU), a natural product was developed that eradicates airborne bacteria, including MRSA. After carrying out successful laboratory based, and live office, trials, agreement was reached with the Burns Unit at Wythenshawe Hospital to undertake a strictly controlled, independent trial, within the healthcare environment. Following consent from the hospital, and from individual patients throughout the trial period, a seven month trial was undertaken to ascertain the effectiveness of this natural anti-microbial product. The results were exceptional, with consistent reductions of bacteria, with a definitive effect on MRSA. A summary of this trial is outlined on the next page.

Trial Objective

To determine if a continuous dispersal of essential oil vapours would reduce the airborne level of bacteria.

Media used

Columbia Blood Agar (CBA) for total count
Mannitol Salt Agar for isolation of Staphylococcus aureus (MSA)
Air Sample machine (Germ sampler GS100)

Presumptive colonies were further identified by Staph kits and their susceptibility to methicillin was also carried out.


  1. Three side rooms, each occupied by one patient, were selected within the Burns Unit
    2. One room was selected as the control room (no machine/essences were placed in here)
    3. Bacterial counts were taken from each room at the start of the trial daily, over a one week period to determine initial background readings, and to allow for comparison once the machines were switched on in two of the rooms
    4. The machines were switched on in rooms B and C in April 2006. On day one the machine output was at 30%. This was reduced to 10% output on day two, due to patient tolerance. The machines remained at 10% for the duration of the seven month study.
    5. Sampling was then carried out every week at a fixed day and time for five months.
    6. The essence pots were changed for fresh pots every two weeks.
    7. The machines remained on, but the essences were removed from the first week of October (month 6) and remained running without the essence until the end of month seven.
    8. Samples were taken at the same day and time through months six and seven.
    9. An MRSA outbreak occurred in room B during month seven. Sampling continued through this period, under strict supervision.

    All patients were provided with study information and consent forms.


  • Figure 1.1: bacterial count reduction in room with machine switched on (See bottom page)

Results Combined

Figure 1.2: Number of MRSA positive patients in three rooms over 7 months (See bottom page)

Results Continued

Figure 1.3 Number of MRSA colonies identified in each room over 7 months (See bottom page)


The overall objective for all studies was to determine if continuous dispersal of essential oil vapours reduce the airborne level of bacteria.

In the Hospital Study, the constant output level in the hospital was 10 % due to patient tolerance. This was effective in reducing airborne bacteria levels, taking between 10 days to 2 months to produce a substantive, long term effect.

Figure 1.1 (See bottom page) highlights the results from one of the rooms (room C) that contained the machine and essence. The results show a reduction in airborne bacterial count once the machines were switched on. The same trend in airborne reduction was observed in the other test room. When the machines were switched off, sampling continued and the numbers of airborne bacteria began to slowly increase as the effects of the essences diminished. The sampling continued to the end of January which showed the levels of airborne bacteria beginning to increase toward levels observed at the beginning of the trial (data not shown).

The effect in the control room mirrored that of the two test rooms containing the machines, with a reduction in airborne counts, however the effect occurred later in the study. As the vapours could be detected in the corridors and in the control room, the essences would have also diffused into this environment, albeit over a longer time period.

MRSA positive patients were present in all three rooms during the trial period (see Figure 1.2 bottom page), however MRSA isolates were only detected in the air in the control room, where no vapours were directly dispersed (room A), as shown in Figure 1.3 (See bottom page) . When the essences were removed from the machines at the end of month 5, there was an increase in the numbers of MRSA isolated, and an MRSA outbreak occurred on the ward. These MRSA isolates were tested against the vapours in the laboratory and data showed that their growth was inhibited by the vapours. 

Laboratory test conducted by Melbec Microbiology Laboratories:

Zone of Inhibition & Determination of Inhibition of Growth by Vapours

Date of Report:            09.6.14

MelBec Reference          62

No. of samples:                 1

Sample Details:

Name of Product:             Antibacterial Essential Oil – GUARDIAN

Batch Number:                 NA

Method Overview

Test Organisms:

E.coli NCTC 10418

Enterococcus hirae NCTC 13383


Cl. difficile NCTC11209 spores

Zone of Inhibition:

A lawn of each of the test of organisms was prepared on the surface of a Tryptone Soy Agar plate.

1cm3 squares of filter paper were soaked in the test product and then placed onto the surface of the plate.

The inoculated plates were incubated at 37⁰C ± 2⁰C for 48h. The Cl. difficile was incubated under anaerobic conditions.

After incubation the plates were examined for zones around the filter paper.

Inhibition by Vapours

A lawn of each of the test of organisms was prepared on the surface of a Tryptone Soy Agar plate.

1cm3 squares of filter paper were soaked in the test product and then placed into the lid of the petri dish.

The plates were sealed with autoclave tape.

The inoculated plates were incubated at 37⁰C ± 2⁰C for 48h. The Cl. difficile was incubated under anaerobic conditions.

After incubation the plates were examined for inhibition of growth.

Results – Zone of Inhibition



Enterococcus hirae 

Clostridium difficile

Zone sizes of between 40mm and 50mm were achieved for all four organisms.

The zone sizes demonstrate that the test product exhibits an antimicrobial effect on the test organisms.

The E.coli gave visible zones however there were colonies growing within the zone indicating that the organism showed some resistance to the test product.

Inhibition by Vapours



Enterococcus hirae

Cl. Difficile

Zones of inhibition were achieved for all the organisms when exposed to the vapours of the test product. The zones were directly above the filter paper.

The zone sizes demonstrate that the test product exhibits an antimicrobial effect on the test organisms.

The size of the zones varied with the largest zone being achieved against the Cl. Difficile spores and the smallest zone achieved for the Enterococcus hirae.


Both test methods demonstrate that the test product has antimicrobial properties against the test organisms.

Report Authorised By:

Dawn Mellors


Technical Director

Melbec Microbiology

Melbec Microbiology – laboratory responsible for Vapour tests

Accredited organisations website – listing of all accredited UK laboratories.

Laboratory reference

Medical Microbiology

Testing can be carried out based on the methodology of AATCC 100, and both standard and bespoke methods to support your research or your product claims

Cosmetics and Personal Care

Testing is carried out to assist in compliance with the Cosmetic Regulation (EC) 1223/2009. We also offer testing for batch release to required USP’s.

Biocidal Products

To support your product claims and to assist in product compliance, we carry out testing to a range of British and European Standards. 

Smith and Nephew Technical Services Group – laboratory responsible for Care Home trial

The Smith & Nephew Technical Services Group offers a world class laboratory testing, prototype manufacture and consultancy service for the healthcare industry. 


Dr. Valerie Edward Jones

Professor of Medical Microbiology, Head of Research Development

Academic Interests

antimicrobial resistance, alternative antimicrobial therapies


MALDI-TOF-MS and identification of microorganisms

Teaching Specialisms

Microbiology Infectious Disease Immunology

Research Interests

Infectious disease, Wound infection, Toxic Shock syndrome, Antiseptics & Essential oils