• Shepherd Filters named 2019 “Product of the Year” – AIRAH Awards

    It’s official!  Shepherd Filters are the best extraction hood grease filter on the planet.

    We are delighted that Shepherd Filters won the 2019 “Product of the Year” AIRAH Award and feel honoured to be distributing this product in New Zealand.

    Wanting to learn more about this disposable kitchen grease filter? >> click here

    Read the original announcement post from Shepherd Filters themselves here.


    Our Dry Ice Blasting service showed its face in Food Technology’s special November issue – “Create Clean.”  

    Food Technology Create Clean Issue


    Read on for the transcript, or download the original article here.


    Dry ice blasting is the most sustainable cleaning method available to the food and beverage industry ever, believes Matthew Prestidge, Industrial Hygiene Advisor for Presco Environmental. “It always amazes me how we can completely sanitise a surface to meet food production standards, yet use no chemicals at all!”

    Presco Environmental, a family-owned business based in Taranaki that provide industrial cleaning services to the NZ food and beverage industry, are now offering this innovative cleaning technology which not only helps food production factories in their visions towards a more sustainable future, but is a solution in places that were previously very difficult to clean.

    Dry ice blasting is exactly as the name says; cleaning by blasting dry ice. Small rice-sized pellets of dry ice (CO₂) are blasted with compressed air at the dirty surface. The extremely low temperatures of the dry ice (-78C˚) kills any bacteria and freezes the soil, which becomes brittle and flakes off. The pellets sublimate on impact, leaving only the dislodged soil to sweep up off the floor! Being non-abrasive, dry ice leaves the surface underneath the soil in perfect condition.

    Dry ice blasting is a “net-zero” carbon footprint cleaning methodology- recycling the world’s number 1 waste product (CO₂).

    Aside from sustainability, dry ice blasting comes with a slew of other benefits, says Matthew. “CO₂ is a non-conductive gas so is perfect for electrical plants; it can clean around wiring and sensors while they are still live! No water means it’s perfect for dry environments like powder plants as production can resume immediately after the job. No time is wasted waiting for the plant to cool down, dismantling and reassembling or waiting for it to dry out.”

    Dry ice blasting is used widely overseas but is relatively new to us in NZ. It is a popular cleaning method in the automotive and restoration industries. Seeing its sanitation properties, Presco Environmental are excited to bring the technology to the food processing industry.

    Matthew says in the 3 years Presco Environmental have been providing the service, they are seeing more and more plants are looking to dry ice blasting as a sustainable cleaning solution to a difficult cleaning problem. “It’s so satisfying to see the amazed look on a customer’s face when they see what [dry ice blasting] can do. We recently did a job at a big baking company for the second year in a row; cleaning baked on carbon build-up out of their huge industrial ovens and off their conveyors. Previously they had had to shut down for a couple of days while cleaners wiped over all the equipment and then did a chemical clean. They would then have to run a couple of shifts for all the residual chemical and carbon mix to settle. Dry ice blasting has saved them 3-4 days of production time!”

    Presco Environmental have experienced and trained dry ice blasting technicians that understand the critical hygiene requirements of the food processing industry and service NZ-wide. If you have a difficult cleaning situation, would like to clean without using chemicals or water or would just like to find out more about this amazing technology, call the Presco team on 0800 PRESCO (773726) or visit https://prescoenvironmental.co.nz/services/dry-ice-blasting/ .


    -Food Technology Create Clean November 2019


  • Shepherd Filters: Why are they the solution for me?

    The purpose of a kitchen grease filter is to be the exhaust system’s first line of defense, preventing grease accumulation and the subsequent risk of fire.  Read on to discover six problems with standard metal grease filters, and more importantly, the six solutions Shepherd Filters provide.

    Shepherd Filters protect the exhaust system above kitchen staff frying chicken


    Standard metal filters only stop between 20-40% of the airborne grease from entering the exhaust system.  This results in a build-up of grease in the hood, duct and fan, meaning frequent cleans are an ongoing cost.


    Shepherd Filters are 100% natural wool, providing the best solution by capturing up to an impressive 98% of airborne grease before it enters your kitchen exhaust.  This leaves you with a clean system, 365 days of the year.

    Special stainless-steel Shepherd Filter frames are easy to use and come with the guarantee that they are:

    • UL1046 flame barrier tested
    • Airflow tested & certified; and
    • HACCP approved


    Cleaning grease filters is an ongoing problem that can be expensive, disruptive and difficult.

    Using a filter exchange company:

    • Filters are sometimes cleaned sooner than needed, or alternatively, left too long.
    • Exchange companies can be disruptive if they arrive during service times.
    • Sometimes kitchen staff will still have to spend additional time washing filters in between exchanges.

    In-house cleaning:

    • Time consuming and high labour cost.
    • Excess water and unnecessary exposure to unpleasant chemicals can be a waste and also very costly.
    • Environmentally unfriendly.
    • Potential cause of dishwasher breakdowns.
    • Not always cleaned thoroughly.


    In comparison, Shepherd Filters will save you time and money.  This solution is extremely user-friendly and filters can be changed and disposed of in less than one minute!  Other benefits include:

    • Shepherd Filters are 100% naturally fire-retardant wool.
    • They are 100% biodegradable.
    • This solution allows you to only change the filters that need changing.
    • Disruptions are minimised as filters can be changed in the morning before turning your equipment on, or in the evening after the final clean down.



    IRHACE HVAC Hygiene Best Practise Guideline requires a hood and its exhaust plenum to be checked at less monthly for excessive grease accumulation.  It also requires the hood and plenum to be cleaned at least annually.  This is costly, messy and disruptive, and the grease can build-up in a system as fast as one month.  Any excessive grease accumulation will increase fire risk, and this can happen very quickly between cleans.  Furthermore, it is important to check the thoroughness of the clean as responsibility can still be placed on the restaurant.  Clauses or fine print on certificates issued by cleaning contractors can cause insurance companies to void claims in event of a fire.  Shepherd Filters frequently inspect kitchen exhausts after scheduled cleans and find:

    • Sub-standard cleaning has occurred; or
    • The entire system was not cleaned due to poor access.

    Here are real-life examples, just days after a clean:

    evidence of incomplete duct clean


    Shepherd Filters stop you guessing when your system is dirty.  A massive saving occurs in the reduced hood, canopy and duct cleaning as Shepherd Filters protect a clean system.  All that is required is a simple mini spot inspection and clean when scheduled. The images below prove how drastically Shepherd Filters reduce grease accumulation inside a hood.

    Shepherd Filters Canopy solution

    L: hood interior after 4 months with Shepherd Filters; R: hood interior after 2 years with Shepherd Filters



    Cleaning filter gutters is an ongoing and messy task that is often overlooked or only partially completed by filter exchange companies.  IRHACE HVAC guidelines requires that gutters are checked monthly.  Left untouched, these also pose a fire risk.


    Shepherd Filters trap the grease in the wool, reducing the amount of grease draining into the gutters.  This reduces labour costs and fire risks.  Below are true examples:

     Grease accumulation in gutters with and without Shepherd Filters



    Grease can build up very quickly on a fan and easily go unnoticed.  This affects airflow and causes unbalanced fans and excessive loading, which can all bring about premature failure of the fan.

    Recently, Shepherd Filters had a client that discovered his kitchen exhaust system had never been cleaned correctly, causing it to fail.  The fan was replaced, and the entire system was cleaned thoroughly.  Shutting the restaurant to do this resulted in a loss of income greater than $30,000 and this was not covered by insurance. 

    Evidence of grease build-up on fan and roof

    Solution #5 CLEAN FAN AND ROOF

    Shepherd Filters will capture up to 98% of airborne grease before it enters the exhaust system.  This will not only keep your fan cleaner, but also extend its lifespan and improve the airflow throughout the entire system.  Reduced grease build-up also means a reduction in the frequency of rooftop and equipment cleans, again saving you money.


    Problem #6 FIRE RISK

    Although insurance exists for once a fire occurs, it can surely be agreed that preventing a fire is the overall objective for everyone.  Due to substandard cleans or grease build-up between times, there can be potential fire risk just weeks after a duct clean.  Kitchen exhaust fires caused by a build-up of grease lead to insurance companies rejecting rebuild claims and never covering loss of income.  Many restaurants never recover from a fire, due to the costs of letting staff go, loss of income and fixing the damage.

    Restaurant destroyed by grease fire


    Shepherd Filters greatly reduce the grease build-up between cleans.  This reduces your risk of fire spreading throughout the system, and allows any fire suppression systems to function correctly.


  • An Introduction to Shepherd Filters: the simple solution to help you and our planet

    Watch Matthew give you a brief introduction to Shepherd Filters. The special product provides an innovative and sustainable solution for your extraction system filtration. Made from 100% wool, they are naturally fire retardant and biodegradable. Shepherd Filters are disposable and can capture up to 98% of airborne grease, as opposed to as low as 20-40% with a standard grease filter.

    Read more about Shepherd Filters here.

  • VIDEO: How to Change a Shepherd Filter

    Let Matthew show you how easy and fast changing a Shepherd Filter can be!

    Need more help? Read our step-by-step instructions here.

  • When Do I Change my Shepherd Filters?

    One of the many benefits of Shepherd Filters is the savings created by only changing each filter when needed.
    But how do you know when to change them? Watch this short video where Matthew explains when to change your Shepherd Filters.

  • How much money will Shepherd Filters save me?

    Every kitchen is unique, therefore Shepherd Filters help everyone to different extents.  Curious to discover how much money your own kitchen can save using this fantastic product?  Fill out the calculator below and become as excited as we are!

    Unsure and wanting help to use this calculator?  Amazed by your results?

    Flick us a message.  We’d love to hear from you.

  • How to Change a Shepherd Filter: A simple step-by-step process

    Wanting to learn how easy it is to change a Shepherd Filter?

    It will take you less than 1 minute!! Follow the simple instructions below.

    Kitchen Staff changing Shepherd Filters

    1. Remove the Shepherd Filter from the hood track by using the bail handles on the frame and place on a flat surface.
    2. Insert fingers on both sides of the frame cover and pull outward. A slight up and down movement will dislodge the frame cover from the frame.
    3. Take the soiled Shepherd Filter and dispose in trash.
    4. Place new Shepherd Filter across the face of the frame. Reattach frame cover with a slight downward push to reengage cover to frame.
    5. Place Shepherd Filter back in its position in the hood tracking.

    CONGRATULATIONS!! With practise, it will take less than 1 minute to change each filter.

    Download our free printable here.  

    Interested in a video tutorial? Click here.


    E-coli bacteria

    E-coli bacteria

    You have a filtered air supply system? The the filters were recently changed out? Should be all compliant then?

    Sorry team, its not quite that easy. Particulate matter is coming through those air filters, as we speak!

    To quote this Camfil article,  with outdoor air carrying 200 to 1,500 bacteria per cubic metre, an air-conditioning system with a capacity of 10,000 m3/h can potentially take in 2 to 15 million bacteria each hour and seriously contaminate food & beverage production

    Scary stuff!

    All air filters are designed to capture a percentage (important point,) of the particulate matter (i.e. dust, soot, smoke, pollen, mould, bacteria) suspended in the air passing through them.

    (And that’s making an assumption that there are no leaks around the filter holding frames or supply air ducting – letting 100% of that particulate matter through!)

    So what happens to the percentage that is not trapped in the filters?  It all passes through to the clean side of your air filters and travels on through the components of your ventilation system, eventually finding its way into your clean factory environment.

    Dirty Condenser Coil

    Dirty condenser coil

    Okay, lets be clear about this. We are only talking microscopic particles, within the acceptable air quality standards of your factory.

    However, that does not take away from the fact that this particulate matter is building up internally in your HVAC system, clogging condenser fins, creating bacteria colonies around heat exchangers and contaminating supply air duct work.

    If this accumulated foreign matter is not cleaned away and the surfaces sanitised, sooner or later it’s not hard to see that you are going to have issues with the air quality in your factory.

    So, what is the answer?

    A documented, annual hygiene cleaning schedule for your ventilation system will solve this issue for you. This will compliment the mechanical servicing and filter replacement programs you have in place currently.

    This is not usually a task undertaken by factory operators or refrigeration engineers. Look for a reliable ventilation hygiene contractor who has the correct equipment, training and experience to clean and sanitise your:

    • filter rooms
    • air plenums
    • air supply fans
    • air supply ducting
    • condenser coils
    • condenser drain trays and pipework
    • air diffuser grilles

    How often do I need to inspect and clean my Ventilation system?

    This will depend on the environment outside your factory and the standard of air quality required inside your factory. The best answer is to engage an IAQ consultant to establish this for you.

    In the meantime, as a guide, the standard BS EN 15780:2011 contains the following table for recommended inspection intervals.

    Ventilation inspection frequency chart

    Get this in place and you can rest easy that the amount of bacteria entering your factory is under control!

    About the Author.


    Matthew Prestidge photo

    Matthew Prestidge is an Industrial Hygiene and Clean Air consultant for Presco Environmental Services in New Zealand.  Creating more sustainable environments on industrial sites since 2006, Matthew has seen the good, the bad and the ugly and knows what is required to “clean up”.

    Matthew offers a free consultation and professional advice to the food industry for any industrial cleaning or hygiene issue.  Contact him at matthew@presco.co.nz

  • 9 Critical Steps for Correct Removal of Dirty Air Filters

    Very Dirty Air Filter!

    Very Dirty Air Filter!

    It is the time of year again for Dairy Factories to perform their winter maintenance tasks. This includes the very important replacement of any HVAC air filters that are due to be changed out.

    While this diligent attention to air quality is great, how do you make sure that when you disturb these air filters, all of the dirt and pathogens collected up in them over the last season does not become air-borne again and end up contaminating your factory?

    Even more importantly, how do you make sure the service technicians are not risking their health when handling these bacteria-ridden, allergen-inducing objects?

    Here’s some trade tips to help you do a good job of this.

    1. Protect yourself from air-borne contaminants by wearing a well-fitted respirator. Disposable P1 grade is fine.
    2. Have a bundle of 60-80 litre (or approx. 900 mm wide 1200 mm deep) heavy duty plastic bags on hand.
    3. If taking dirty filters back through food production areas, set up a ‘red-line’ and have a person working either side. The person on the ‘dirty’ side will pass the bagged dirty filter over the red-line to the person on the ‘clean’ side who will take the filter out through the plant.
    4. Ensure the air moving fan is switched off – air flow will quickly circulate any dislodged dust, sending it to exactly where you don’t want it!
    5. Remove the dirty air filter carefully, avoid jerky movements that will dislodge the dirt and make it air-borne. Sometimes the filter is stuck to a seal gasket so carefully lift this away from one corner and work your way around the filter slowly.
    6. Place the dirty filter in a plastic bag and tie off the opening or use a cable tie or packing tape to completely seal off the opening.
    7. Double bag the filter for extra protection – steel framed filters particularly can pierce one layer of plastic easily.
    8. Dispose of filters and any disposable personal protective equipment immediately in an approved waste facility.
    9. Clean and sanitise your work area after all of the dirty filters have been removed, bagged and disposed of.

    Now you are good to commence fitting the new air filters.

    If you need assistance or advice with the correct removal and disposal of old air filters, Presco Environmental Services have IAQ consultants and on-site service teams available to help you – call us on 0800 773 726 (0800 PRESCO) or email sales@presco.co.nz 

    Want more information? Contact our friendly team below:

    Get In Touch

0800 773 726
06 278 0712
PO Box 530, Hawera, 4610
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