2.Listeria in care and healthcare environments

Environmental risk in care and healthcare settings

The risk of Listeria in care homes and hospitals is not limited to the kitchen. It comes from the whole environment, including the building, the equipment within it, the activities that take place, and the constant movement of people, food, and equipment between areas.

Let’s explore…

Understanding how easily Listeria can survive and spread within a building highlights why strong environmental controls are essential.

This covers the physical environment and the items within it that can allow Listeria to survive if they are not properly controlled. Care homes and hospitals contain many connected spaces, such as kitchens, wards, treatment rooms, dining rooms, corridors, and toilets. These spaces form one shared environment rather than separate, sealed areas. Equipment within these spaces can support the survival of Listeria if it is not cleaned and maintained properly. This includes fridges, freezers, trolleys, serving units, small kitchenettes, sinks, drains, doors, handles, and food transportation equipment. Damp surfaces, damaged areas, and equipment that is difficult to clean provide ideal conditions for Listeria to survive and spread.

This covers the everyday activities and movement that can transfer Listeria from one place to another. Daily activities such as food service, waste handling, cleaning, and patient care all take place within the same environment. If clean and dirty activities are not well controlled or kept separate, bacteria can be transferred between tasks through hands, equipment, cloths, or surfaces. There is constant movement of people, food, equipment, and waste throughout the building. Staff move between kitchens, wards, toilets, and service areas, while supplies are brought in, moved around, and taken out. Each movement and each point of contact increases the risk of cross-contamination, allowing Listeria to spread.

Practical environmental controls

Listeria survives particularly well in damp places, cracks or damaged surfaces, and hard-to-reach spaces that are not cleaned thoroughly. Unlike most food poisoning bacteria, Listeria can tolerate low temperatures, which allows it to survive in cool or chilled areas. In care and healthcare settings, these conditions are often found around sinks, cleaning equipment, food preparation areas, fridges, and equipment with joints or seals where moisture and food residues can collect.

Because of this, environmental controls must be applied consistently across the whole building. Small failures, such as missed cleaning, damp equipment, or unclear responsibility for shared areas, allow Listeria to survive and multiply unnoticed.

What to do…

Practical environmental controls that help prevent Listeria from becoming established in the environment include:

  • Following cleaning schedules exactly as written
  • Making sure shared and high-traffic areas have clear cleaning responsibility
  • Keeping equipment clean and fully dry after use and cleaning
  • Limiting movement between clean and dirty areas where possible
  • Cleaning equipment before it is moved between rooms or departments
  • Reporting damage, leaks, condensation, or pooling water promptly

The challenge of biofilms

Biofilms are one of the biggest environmental challenges when controlling Listeria. A biofilm is a thin, sticky layer of bacteria that attaches firmly to a surface. Once formed, simple wiping will not remove it. The bacteria underneath are protected and can survive cleaning, allowing contamination to return.

Let’s explore…

Biofilms commonly form in damp areas, hard-to-clean spaces, damaged surfaces, frequently touched areas, and places that stay moist for long periods. Typical high-risk locations include door seals and gaskets, drains, sinks, taps, floor edges, cracked flooring, fridge and freezer interiors, and equipment with joints, screws, or crevices.

Preventing biofilms through consistent cleaning and moisture control is far easier than removing them once they are established. The aim is to make the entire building hostile to Listeria and to deal effectively with any biofilms that develop.

What to do…

To prevent and remove biofilms:

  • Clean before disinfecting to remove dirt that blocks sanitisers
  • Use the correct sanitiser and follow instructions exactly
  • Allow full contact time so the product can work
  • Use scrubbing where needed to break up the biofilm layer
  • Include hidden areas in deep cleaning, such as drains, seals, and joints
  • Check that cleaning is effective, using visual checks or swabs if used
  • Keep areas dry by fixing leaks, drying equipment, and preventing pooling water
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