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What are the best non-corrosive sanitisers for the food industry? December 21, 2020

 

 

image of corrosion and rust

 

Issues with corrosion: What does it mean for a manufacturer or problem solver in the food industry?

I’ll jump straight in – what does it actually mean for a plant manager to have corrosion in his plant?

Well, if you’ve experienced it before, or you’re experiencing it now, you probably know what I’m going to say next.

Corrosion is premature degradation of capital equipment and plant, often caused by highly acidic or highly alkaline chemicals. 

Corrosion creates foreign matter in your food production plant.
Which leads to more reactive maintenance.
Which increase repairs and maintenance (R&M) expenses, along with potential food safety and quality issues.

Eventually, if the corrosion gets too bad, a large capital investment will be required to replace the corroded equipment.

But it’s not just financial.

The more important issue in a food processing environment is food safety.

Corroding surfaces are no longer hygienic. Pathogens can get a foothold and be much more difficult to eradicate in cleaning.

Corroding equipment can also leak foreign matter, i.e. fine dust, rust particles or flaking surface coatings. This puts the food product at high risk of contamination.

You get the picture.

Being involved in food manufacturing, you probably knew most of that. Possibly even experienced it in your plant before.

 

Why are sanitisers corrosive?

So, what causes all this to happen?

Corrosive sanitisers.

Yes – they are one of the biggest culprits of corrosion in food factories.

Because food manufacturers have such a small margin for error in their HACCP plans, they often become dependent on highly toxic agents to wage war on pathogens.

Sodium Hypochlorite is a prime example.

Sodium Hypochlorite is a strong alkaline. At the general 5% solution, it sits around pH 11, with some more concentrated solutions (10-15%) closer to pH 13.

Chemicals this basic will be highly corrosive to metal surfaces (not to mention human skin!). Chemicals on the other end of the scale – acidic – cause a similar reaction.

 

The ‘Vicious Circle’

If not careful, food producers can get trapped in an unfortunate circle of events.

Corrosion creates an environment that supports pathogen growth and is more difficult to clean. More pathogens equal more frequent and more aggressive sanitising.
This equals more corrosion.
Repeat.

 

vicious cycle of corrosive sanitisers and pathogen growth

 

The ironic thing about this is, the pathogens will be protected by a biofilm, which will become resistance to highly acidic or alkaline chemicals – protecting the pathogens beneath.

 

Sanitisers to watch out for:

If you are trying to avoid corrosion, be wary of these two common surface sanitisers:

  • Sodium Hypochlorite (NaOH)
  • Peracetic acid (C2H4O3)

 

Sodium Hypochlorite NaOH

  • 5% solution = pH 11.
  • 10-15% solution = pH 13.
  • Strong alkaline (basic)

Sodium Hypochlorite is a chlorine-based surface disinfectant. It is possibly the most widely used, especially in the food industry, due to it being easily procurable, effective, and relatively cheap.

It does come with its downfalls though. Due to their high pH, hypochlorites are corrosive to metals and skin. Metals will develop a pitting or form a film when in contacted with hypochlorites. When in contact with aluminium, hypochlorite will generate hydrogen gas.

Full ‘Dangerous Goods’ storage and handling precautions are required.

 

Peracetic acid (also known as Peroxyacetic acid, or PAA)

  • 5% solution
    • IXOM ‘Perform’ SDS states pH of <1.5
    • Solvay’s ‘Proxitane’ SDS states pH of <2.
  • Strong acid

Peracetic acid solutions contain a mixture of peracetic acid, acetic acid, and hydrogen peroxide. It is a sanitiser/disinfectant, effective against all microorganisms, including bacterial spores.

In concentrate form, PAA is highly corrosive and unstable. Strong solutions can corrode metals and skin.

At pH neutral, PAA is less corrosive but as shown above, major industry brands promote solutions that are highly acidic.

 

Non-corrosive options

These two surface sanitisers are non-corrosive and can be used in the food industry:

  • Quaternary Ammonium Compounds (QAC)
  • Hypochlorous Acid (HOCl)

 

Quaternary Ammonium Compounds – QAC’s

  • 1% solution: Kemsol ‘BAC-TECH’ – pH 7.5
  • 5% solution: Ecolab ‘QAC Disinfectant Cleaner’ – pH 9.3 – 10.3
  • 10% solution
    • Hygiene Technologies ‘Deep Blue’ – pH 7.5 – 9 (same pH in 30% solution)
    • Kemsol ‘BAC-STOP’ – pH 10.5

 

Quats have also been widely used in the past, as they are cost effective and provide broad spectrum control. They are non-corrosive to metals. Being cationic (positively charged) in nature, they are ideal as residual sanitisers.

Ironically, that same feature is why they have largely fallen out of favour. Whilst these are non-corrosive, some food safety authorities have not recommended or even banned the use of QAC’s in food production facilities. This is because it ionically ‘bonds’ to surfaces if not thoroughly rinsed off. This can result in it contaminating the food product, therefore posing a health risk to consumers.

 

Hypochlorous Acid

  • Concentrate solution: Envirolyte NZ ‘Anolyte’ SDS states pH of 7

Hypochlorous acid (HOCl) solutions are often generated through electrolysed water technologies. Salt and water are given an electrical charge to produce a chemical compound with HOCl as the active ingredient. It is highly effective against a wide range of pathogens (80 – 120 times more efficacious than Sodium Hypochlorite[1]) and is becoming increasingly popular in the food processing industry.

NOTE: Not all HOCI solutions are pH neutral.

When the solution is pH neutral, i.e. ANK Neutral Anolyte, it will not corrode any surfaces or materials.

Remember the ‘Vicious Circle’ we talked about.

Well, being pH neutral, the biofilm thinks it is just water, so the Anolyte solution is not resisted by the biofilm. It can be thought of as the ‘Trojan horse’ of sanitisers. Learn more about this here.

Non-corrosive, non-toxic, non-DG and highly effective!

In my humble opinion, HOCI based sanitisers with proven efficacy are the best non-corrosive sanitiser available for food producers.

 

So, a quick summary …

Common sanitisers to avoid due to corrosiveness:

  • Sodium Hypochlorite
  • Peracetic Acid

Non-corrosive sanitisers:

  • QAC based sanitisers
  • HOCl based sanitisers
Common sanitisers used in the food production industry comparison

Our recommendation: Hypochlorous Acid (HOCl) based sanitisers.

HOCl enables you, as a food producer, to avoid corrosion in your plant whilst maintaining a hygienic and food safe environment.

ESPECIALLY, if you are currently using Sodium Hypochlorite. (remember the 80 – 100 times less effective than hypochlorous!)

If you are using a corrosive sanitiser, I would urge you to investigate other non-corrosive options today. Do not procrastinate. The sanitiser being used in your plant is not waiting around. It’s quite possibly eating into your plant equipment as you read this.

Want to learn more about a hypochlorous acid-based sanitiser and disinfectant that is:

  • non-corrosive,
  • non-toxic, and
  • non-dangerous goods?

Contact us about ANK Neutral Anolyte today or find out more here (scroll down the page for more information).

 

Does this analysis match what you have experienced in your food processing career? Or found something works even better? Really interested to hear and always keen to learn! Feel free to get in touch below.

 


 

 

Denver Prestidge, business development manager

 

About the Author

Denver Prestidge is a fresh Industrial Hygiene and Air Quality apprentice for Presco Environmental.

Focused on sourcing and developing innovative, industry leading products for New Zealand’s food producers, Denver is always looking for ways to challenge and improve the status quo.

If you would like to get in touch with Denver, feel free to reach out at any time: denver@presco.co.nz.

 

 


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