Firstly, let’s look at what enzymes are from a cleaning and hygiene perspective and also what they are not
- They are specialized types of proteins produced by microorganisms to help them break down food sources, and so make them easier to digest. In most cases this is by hydrolyzing the food source (making it water soluble) to enable it to be assimilated easily by the organism
- Enzymes are not alive, only the organisms that produce them are
- Enzymes can be ‘made-to-order’ by microorganisms to very specifically target virtually any material of organic origin
- Enzymes are catalysts – they start a process happening and sustain its action, but are not themselves consumed in the reaction, unlike “standard chemical” reactions such as caustic soda converting fat into soap for example. This is why only a tiny amount is needed in comparison to a chemical to achieve the same end result
- Given the correct very specific operating conditions, an enzyme will achieve the desired chemical reaction faster, far more efficiently, and using only a fraction of the resource than any type of synthetic chemical compound and achieve a level of specificity in reaction that can’t be matched. And once they are finished, they biodegrade with no harmful by-products produced
Given the above points, it is correct to think that enzymes are an almost perfect agent for cleaning, and in the perfect world that is true. However, in reality there are a number of factors that have limited their use in food and beverage cleaning situations. Before we get into those, it is important that we distinguish between true enzyme formulations, and those that are actually mixtures of live (but dormant) microorganisms with some enzymes present.
A common product in NZ that fits into the latter category are the products produced by Bio-Zyme Ltd. These contain mixtures of dormant non-pathogenic bacteria, along with a food source and other excipients. When diluted down ready to use, the idea is that that bacteria are “woken up” and start producing enzymes to break down the food soiling they come in contact with. It is interesting to note that although some of these products have MPI “C” approvals (for use in Animal Product processing), the restrictions on their use in Dairy Processing (which is far more vigorously scientifically examined), are quite acute. The below is taken verbatim from the MPI Dairy Maintenance Compounds register:
- For use in external areas only
- Not for use near air intake/ventilation to processing areas
- Not for use on milk transport tanks or silos and tanks for the storage of milk, food or ingredients.
Note: Bio-Zyme products contain yeast, molasses, malt and sugar. Use within processing environments is not acceptable due to the potential for contamination. If complaints arise the Recognition may need to be withdrawn.
So, what are the down-sides that have prevented enzyme based cleaners becoming the norm in open-area cleaning situations in food processing?
- As enzymes are catalysts and are so good at breaking down protein bonds, they can be more hazardous than traditional chemicals such as caustic soda when they are sprayed or foamed around in an open area. Aerosolised droplets can enter the airways or mucous membranes and keep working for a lot longer than the localized effects of aerosolized caustic for example. And because there is no pain or burning sensation involved, the staff member will not realise something is wrong. This problem is not insurmountable, with good controls and PPE etc, but it is a risk
- To work at optimum efficiency (and they quickly become much more expensive than traditional chemistry if not used optimally), enzyme cleaners need to be diluted and maintained within a specific temperature range while they are working on the surface. This is normally in the range of 35-45°C. Not only could this be impractical, depending on what temperature water lines are available and how tightly they are kept within range, but it is almost impossible to maintain that temperature on the surface for a given time period in a cold boning room for instance
- Enzyme formulations need specific stabilizing chemicals in them to stop the proteases from attacking the other enzymes in the mixtures. These stabilizing chemicals are not compatible for long-term use in PVC pipe systems that are used in the majority of central-foam systems in NZ
- Only a tiny amount of enzyme is needed to start the process of breaking down organic material, so simply rinsing them off equipment after use is taking a big risk, unless you follow it up with a strong solution of an acidic or oxidizing sanitizer to ensure any possible residual enzyme is properly de-activated. The risk is that if a tiny amount is left you could end up with tenderized meat or rancid cheese or very short shelf-life vegetables. Quat sanitisers which are very common in NZ food factories do not de-activate enzyme residues
In summary, enzyme technology is experiencing rapid growth because of its green and efficient and selective credentials, but the technology does not yet exist to overcome these issues in open-area cleaning. However, in Clean-In-Place situations, it has a lot more practical useability.
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