Is visual motivation for cleaning surfaces in the kitchen consistent with a hygienically clean environment?

Abstract

Cleaning is a method at the disposal of domestic cooks for curtailing the dispersal of foodborne pathogens in the process of preparing food. The observation of visible dirt/soil ‘in the wrong place’ operates as one of the stimuli for action. This paper makes a transdisciplinary contribution to understandings of cleaning as a practice for ensuring safety in the kitchen, and it is mainly focused on the (in)visibility of soil or dirt. The social science research included analysis of a consumer survey in 10 European countries where 9966 respondents were asked about motivations for cleaning in the kitchen. This paper draws also on three microbiological tests. First, Portuguese (n = 7) and Norwegian (6) consumers evaluated the visible cleanliness of 10 surface areas in their kitchens, directly and through the visible residue and total bacterial numbers accumulated on a white cotton swab after swabbing the surface areas. Secondly, 15 Norwegian consumers tested if they could visually detect different types of food soils, as these dried on kitchen surfaces. Finally, the survival of Campylobacter and Salmonella in the same soil types was tested under lab conditions as the soil dried out. Cleaning food preparation surfaces “after food preparation” (73%), “before preparing food” (53%) and “when they are dirty” (43%) were the three most common self-reported behaviours. Routine was the most common motivation to clean, but this was age dependent. There was low correlation between visual detection of dirt/soil and bacterial enumeration. Visual detection of soils was dependent on type and concentration of food soils and material of the surface; the soils were more easily detected on laminate surfaces than plastic and wood. Campylobacter died rapidly, while Salmonella survived for at least one week in food soils drying on a countertop laminate surface. Presence of food soils in concentrations that can be detected visually, protected Salmonella against drying. In conclusion, selecting materials where soil/dirt can easily be detected visually in the kitchen surfaces, may motivate consumers to clean and will reduce risk, but establishing a habit to clean surfaces soon after food preparation is also important from a food safety perspective.