vs. Chemicals — Seafood

Seafood plants are traditionally heavy chlorine users, because water and ice volumes are large and because chlorine is cheap, familiar and effective in water. Any comparison that ignores that starting point is not useful. This page compares onsite-generated hypochlorous acid with what a seafood plant actually runs, on the things that decide a programme here: behaviour in high organic load, residues, materials in a permanently wet building, handling, water use and cost. Efficacy against named organisms belongs to each registered product’s label and is deliberately not the axis.

At a glance

Against the chlorine you already use

This is the substitution most seafood plants are actually considering, and it is the most direct one: same chemical family, different pH and different supply model. Bleach arrives as an alkaline corrosive concentrate whose chlorine is mostly hypochlorite ion, and it has to be diluted on site. A near-neutral generated solution keeps its chlorine in the undissociated form and is made at use strength, a few metres from the work.

The practical differences show up in three places. Handling: no concentrate on the floor, no dilution step, no run-outs at 2am. Materials: near-neutral solution is generally gentler on stainless steel and aluminium than high-strength chlorine, which matters in a building that never dries out. And volume: when the cost per litre falls, drains and zone 3 actually get done, which is where a Listeria problem is won.

What does not change: chlorine demand. Slime, blood and protein consume oxidiser regardless of how it was made, so the dose is set by measurement in the water, not by a number copied from another plant.

Against peracetic acid

PAA holds up well in organic load, which is exactly why seafood plants use it, and it breaks down to acetic acid, water and oxygen. Its costs are the concentrate and the vapour: a corrosive, pungent drum on site, and odour management in cold, enclosed rooms where air changes are limited and staff are working all shift.

The usual outcome is not replacement but reallocation. Plants keep PAA where a process has been validated around it — often a specific water or CIP application — and move open-surface and environmental work onto generated solution, which reduces the amount of concentrate stored and handled without disturbing anything that has been validated.

Against ozone

Ozone is a genuine competitor in seafood, because it is also generated on site and has a track record in water systems and chilled storage. The trade-offs are real on both sides. Ozone has a very short half-life, which is good for residues and awkward for contact time; it is demanding to control in high-organic water, where demand consumes it quickly; and being a gas, it brings monitoring, ventilation and exposure management that hypochlorous acid at use strength does not.

Where a plant already runs a well-controlled ozone system in water, there is rarely a case for ripping it out. The complementary case — ozone in a water application, generated HOCl for surfaces, ice and the environment — is more common than a head-to-head replacement.

Against quats

Quats are stable, inexpensive and leave a residual film, which is why plants like them and why food-contact use is constrained. In a seafood plant the residual is a mixed blessing: it persists on surfaces that will shortly be wet again, it binds to some cloths so the concentration reaching the surface is lower than the bucket suggests, and it has to be managed within applicable limits on food-contact surfaces. Most plants that change keep quats for specific non-contact applications and move volume surface work across.

The cost model, not the price per litre

The method and a worked example are on the sector ROI page.

Where the incumbent still wins

• A validated process built around a specific chemistry. Revalidation costs money; change it for a reason.
• Tasks needing residual activity. Hypochlorous acid leaves none.
• Documented label claims. Use a registered product; generated solution carries none.
• Very high organic load with no practical cleaning step. That is a cleaning problem, and no oxidiser fixes it.
• Depuration and wet storage. Whatever your shellfish control authority has approved.

Questions worth asking any supplier

1. What is the true cost per litre delivered to the task, including freight, dispensers and dilution labour?
2. What is the demand of our actual water, measured, rather than a target concentration?
3. What PPE does the concentrate require, and what does that cost across a season?
4. What is the material compatibility position for our equipment in a permanently wet building?
5. Which authorisation covers each use — water, ice, surfaces — and can you show it?
6. What happens to the programme when a delivery is late in peak season?

Designing the programme, not choosing a product

The useful question is not “which chemistry is best?” but “which chemistry for which task?”. A seafood plant usually ends up with something like this: detergents unchanged, and chosen for fat and protein rather than for price; generated hypochlorous acid for ice, chilled water, volume surface work and the environment; a registered product where a documented claim is needed; peracetic acid or ozone retained in a validated water application; hot water where equipment tolerates it; and whatever the shellfish control authority has approved for tank water.

That is not a compromise, it is a programme, and it is far easier to defend in an audit than a single-chemistry story that does not survive contact with a wet, cold, protein-heavy plant. Two practical notes. Count tasks and volumes, not litres of concentrate: the chemistry touching the most product is the one where consistency matters most, and in seafood that is almost always the ice and chilled water. And write down why each chemistry sits where it does — when a customer, an auditor or a new QA manager asks, the answer should be a document rather than an anecdote.

Frequently asked questions