Hygiene during food preparation, feeding, and storage is as essential for young children's growth and nutrition as an adequate and diverse diet (Dewey and Adu-Afarwuah, 2008). Intestinal infections and diarrhoeal disease in children caused by pathogens transmitted in food is a global public health concern, particularly in low-and middle-income countries (LMICs) (Kirk et al., 2017). In economically disadvantaged communities in LMICs, most food contamination and recurrent foodborne infections originate at the household level, primarily from exposure to faecal pathogens in the domestic environment and caregivers' poor food hygiene practices (Curtis et al., 2000). Interventions that aim to interrupt the transmission of pathogens to children in these settings focus largely on reducing direct human contact with faecal pathogens, with particular attention to safe human faeces disposal and handwashing with soap after defecation (Ejemot-Nwadiaro et al., 2021; Humphrey et al., 2019; Luby et al., 2018; Null et al., 2018; Wolf et al., 2022). Even though unwashed hands before handling food, use of unclean feeding utensils, and inadequate reheating of leftovers with poor storage practice remain critical entry points for children's intake of (re)contaminated food in a contaminated environment (Islam et al., 2013; Motarjemi et al., 1993; Parvez et al., 2017), improving caregivers' food hygiene behaviours has only recently received attention in water, sanitation and hygiene (WaSH) and nutrition literature (Curtis et al., 2011).

Over the last decade, a few intervention trials have attempted to improve caregivers’ food hygiene practices around complementary child feeding in low-income settings of South Asia and sub-Saharan Africa (Gautam et al., 2017; Manjang et al., 2018; Morse et al., 2020; Mumma et al., 2019). They employed behavioural models to understand motivational drivers, and the interventions focused on a wide range of behaviour change techniques such as commitment, modification in the domestic environment, use of prompts and cues, and social rewards to encourage the adoption of safe food hygiene behaviours among mothers and caregivers of young children (Gautam et al., 2017; Manjang et al., 2018; Morse et al., 2019; Simiyu et al., 2020). While the success of these trials in improving targeted behaviours was promising (Chidziwisano et al., 2020a; Gautam et al., 2017; Manaseki-Holland et al., 2021), most of the interventions were of limited scale and short duration (Gautam et al., 2017; Manjang et al., 2018) and implemented with frequent contacts with participants (Gautam et al., 2017; Morse et al., 2020). Evidence about long-term behavioural maintenance in response to such interventions is also limited, to our knowledge, reported only in one food hygiene study in The Gambia (Manaseki-Holland et al., 2021).

Concurrent with other food hygiene studies, we designed a less intensive behavioural intervention to promote food hygiene as part of a larger nutrition-sensitive agriculture trial in Bangladesh. During follow-up visits during the implementation phase, we noted a substantial increase in all promoted food hygiene behaviours compared to the pre-intervention period (Sobhan et al., 2022). Nevertheless, it remained to be seen whether these behaviours could be maintained long-term. Furthermore, safe food preparation, consumption and feeding children are complex processes involving several critical points (Islam et al., 2013) and practising multiple food hygiene behaviours together might be required to substantially minimise the risk of food contamination (Müller-Hauser et al., 2022). Also, these behaviours need to be practised repeatedly during every preparation and feeding event to achieve optimal impact on child health. However, how often multiple food hygiene behaviours are practised simultaneously and consistently remains an open question.

In this article, therefore, we primarily aimed to evaluate the effect of this relatively large-scale, less intensive behavioural intervention on the maintenance of household food hygiene practices at four and sixteen months after the intervention. In exploratory analyses, we also assessed the behavioural patterns to expand our understanding about (a) variations in the practice of several food hygiene behaviours during food preparation and child feeding and (b) consistency in food hygiene practices across multiple observed events.