Documented case · UV-Life customer in San Juan de los Lagos, Mexico
From 8 to 36 hours of shelf life without adding preservatives
A tortilla maker in San Juan de los Lagos, Jalisco (Mexico), producing around 600 kg of maize tortillas a day, installed four UV-C X50 bars above the cooling conveyor, between the griddle (comal) and the packing machine. The owner, Gustavo Romo, reports that mould went from appearing at around 8 hours to appearing at around 36 hours, without changing the dough or adding chemical preservatives.
- ~600 kg/day
- 4 × X50 bar
- Cooling conveyor
- No preservatives
The critical point
The problem was not hygiene, but the window between the griddle and the bag
The tortilla leaves the griddle practically sterile. What determines how long it lasts is not that stage, but what happens in the minutes that follow.
It leaves the griddle with a very low load
The heat of the griddle drastically reduces the microbial load. At that moment the product is in its best microbiological condition of the whole process.
It is recontaminated during cooling
As it travels along the conveyor, the tortilla has high water activity and an exposed surface. Fungal spores suspended in the plant air settle on it.
The packaging traps the moisture
When the bag is sealed, moisture is trapped together with the freshly deposited load. The spores germinate and mould appears sooner than the point of sale needs.
The intervention
Four UV-C bars above the existing conveyor
The installation was made over the cooling section, without modifying the line or stopping production.
Single layer and exposed surface
The tortillas travel flat and separated on the mesh. This is the condition that makes irradiation effective: UV-C light only acts on what it reaches directly.
The exact section: between griddle and packing machine
That is where the initial microbial load with which the product enters the bag is determined. Irradiating earlier or later does not change the result.
No contact with the product, no change of recipe
UV-C light does not touch the dough or add anything to the recipe. The tortilla remained maize, water and lime.
LED technology, not a mercury tube
Over a food line, a mercury tube carries the risk of breakage, with glass and mercury falling on the product. UV-C LED eliminates that risk.
The result
Mould onset went from around 8 hours to around 36 hours
What the customer valued most was not the shelf life itself, but its commercial consequence: more hours without mould mean more points of sale within reach without a cold chain. Shelf life stopped being the limit on the distribution radius.
“Before, the mould came very quickly. I had complaints all the time, returns from the points of sale. After installing the UV-Life equipment, that disappeared. Now I distribute further and the tortillas arrive in perfect condition.”
Real scope of the technology
What UV-C light does and does not do
It reduces the load. It does not guarantee absence.
A lower microbial load on the surface means slower growth and, therefore, more hours before mould becomes visible. That is the whole mechanism, and it is worth stating just as clearly where it ends.
What it does
- Reduces the microbial load on the irradiated surface of the product
- Acts on a section of the process, without adding anything to the formulation
- Does not alter the flavour, colour, aroma or temperature of the product
- Delays mould onset by lowering the initial load before packing
- Works continuously over the line, without stopping production
What it does not do
- It does not penetrate the product: it acts only on the surface it reaches
- It does not reach hidden faces if the product travels stacked or overlapping
- It does not reverse mycotoxins already formed or correct contaminated product
- It does not eliminate spores completely: they require higher doses than vegetative bacteria
- It does not replace good hygiene practices or the plant’s HACCP plan
The wider lesson
Why this case matters even if you do not make tortillas
There is nothing special about the tortilla. What makes it a good case study is that it combines three conditions found in many food processes, starting with fresh doughs and bakery products.
A moist, exposed surface after a heat or washing step
The product is left with a low load but is vulnerable to environmental recontamination before the package is sealed.
A section of the process in a single layer
Without that section, the light does not reach the surface and the technology does not apply. This is the condition that determines whether the case can be replicated.
Short shelf life that limits the business
Whether through wastage, returns from points of sale or distribution radius, shelf life is setting the commercial ceiling.
Wherever all three are present, the mechanism is the same: fresh doughs and bakery products, leafy vegetables after washing, cold cuts and processed meats before packing, and grated and aged cheeses. What changes in each case is the dose, the conveyor speed and the exact installation point.
Frequently asked questions
About this case and whether it can be replicated
Why does mould appear on tortillas so quickly?
The tortilla leaves the griddle with a very low microbial load, but it travels along the cooling conveyor with high water activity and an exposed surface. In that section, spores suspended in the plant air settle on it again. When it is packed, the moisture is trapped together with that load and the spores germinate. It is not a cleanliness problem: it is the initial microbial load with which the product enters the bag.
How much did shelf life increase in this case?
The customer reports that mould went from appearing at around 8 hours to appearing at around 36 hours. These are values from their own operation and from feedback from their points of sale, not a controlled laboratory trial or a guaranteed specification of the equipment. The result depends on the process, conveyor speed, the environmental load in the plant and its hygiene practices.
Does UV-C light replace preservatives?
UV-C light acts on the surface of the product during processing, not inside the dough. It reduces the microbial load before packing, which delays mould onset. In this case the customer operated without preservatives, but the result depends on the process, conveyor speed and the hygiene practices of each plant.
Does the production line need to be modified to install UV-C?
Not in this case. The UV-C bars were mounted above the existing cooling conveyor, in the section between the griddle and the packing machine, without stopping production. What is defined case by case is the mounting height and the number of units, because that determines the dose the product receives.
Is it safe for plant staff?
UV-C light is not a laser and does not cause immediate harm. Even so, direct exposure of skin and eyes must be avoided, just as you would avoid spending hours in the sun without protection. The UV-C X50 bar has no presence sensor: that is why the units are mounted at height, pointed at the conveyor and out of the operator’s line of sight at their workstation, something we define when designing each installation.
Does this case apply to foods other than tortillas?
The mechanism applies wherever three conditions are met: a product with a moist, exposed surface after a heat or washing step, a section of the process in a single layer where the light can reach that surface, and a short shelf life that limits the business. These conditions are met in fresh doughs and bakery products, leafy vegetables, cold cuts and processed meats, and cheeses, with a different dose and installation point in each case.
What does UV-C light not do on food?
It does not penetrate the product: it acts only on the irradiated surface. It does not reach hidden faces if the product travels stacked. It does not reverse mycotoxins already formed. It does not eliminate spores completely, because fungal spores require higher doses than vegetative bacteria. And it does not replace good hygiene practices or the plant’s HACCP plan: it is an additional preventive layer, not a substitute control.
Why LED and not a mercury germicidal tube?
Over a food line, a mercury tube carries two risks that LED does not: breakage with glass falling on the product, and mercury contamination. In addition, UV-C LED emits concentrated within the absorption range of microbial DNA, between 260 and 285 nm, and exceeds 10,000 hours of service life with no tube replacement.
Take the next step
Does your process have a similar section?
Tell us about your line and at which point the shelf-life problem appears. We will check whether there is a usable section and tell you frankly whether the technology applies to your case or not.
Or email us at sales@uv-life.com