Evaluation of the kitchen microbiome and food safety behaviors of predominantly low-income families

Abstract

Bacterial pathogens in the domestic environment present a risk to residents, particularly among susceptible populations. However, the impact of consumer demographic characteristics and food handling methods on kitchen microbiomes is not fully understood. The domestic kitchen bacterial communities of ten predominantly low-income families in Houston, TX, were assessed in conjunction with a cross-sectional food safety survey to evaluate differences in household and surface-specific microbiomes and bacterial foodborne pathogen presence. Three kitchen surfaces within each household, including the sink drain, the refrigerator handle, and the counter, were environmentally sampled and metataxonomically evaluated via targeted 16S rRNA sequencing. Disposable dish sponges were also acquired and examined. Results indicated that alpha diversity did not vary by the households, sampling locations, or demographic characteristics evaluated. Significant differences in beta diversity were observed among the bacterial communities of five pairs of households and between refrigerator handle and disposable dish sponge microbiomes. A total of 89 unique bacterial foodborne pathogens were identified across surface types. Each household contained at least one contaminated surface, and the most common bacterial foodborne pathogens identified were Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae. All parents reported washing their hands before meal preparation, washing fresh fruits and vegetables, and washing cutting boards with soap after use to prepare raw animal proteins. Gaps in food safety behaviors identified included a lack of serious concern for food contamination with germs and inappropriate handwashing, food handling, and cleaning behaviors. The number of unique bacterial foodborne pathogens identified within households was significantly higher among households whose respondent parent reported that they did not consider food contamination with germs to be a serious food safety problem (median: 41.0 species) compared to households whose respondent parent did consider food contamination to be a serious food safety problem (median: 3.0 species; p value = 0.0218). These results demonstrate that domestic kitchen taxonomic abundance profiles vary according to household and surface type. Data suggest that low-income consumers may be at risk of foodborne pathogen exposure from contaminated home kitchen surfaces, and that food safety attitudes may directly contribute to this hazard.

Keywords: consumer behavior; demographic disparities; diarrheal disease; food safety; foodborne illness; indoor built environment; metataxonomics; sanitation.

Figure 1

The alpha diversity of the microbial communities detected among four kitchen sampling locations within predominantly low-income households (n = 10) by household (A) and sampling location (B) as represented by Shannon’s diversity index, Houston, Texas, 2021. Shannon’s diversity index parameter computations were conducted using the averaged relative abundances of taxa between replicate samples.

Figure 2

The relative abundance of bacterial taxa detected at the genus level among four kitchen sampling locations within predominantly low-income households (n = 10), Houston, Texas, 2021. Bars represent averaged relative abundances of taxa between replicate samples. Pathogen-containing genera are indicated with an asterisk.

Figure 3

Foodborne pathogen presence detected among four kitchen sampling locations within predominantly low-income households (n = 10) according to household and sampling location, Houston, Texas, 2021. Red color indicates that the respective sample contained a bacterium known to cause foodborne illness (FDA, 2012). Green color indicates that bacterial foodborne pathogens of interest were not identified within the sample. Pathogen-containing genera are indicated with an asterisk. The number of unique species level identifications per pathogen containing genera included: Bacillus (23), Brucella (2), Citrobacter (6), Enterobacter (6), Enterococcus (6), Klebsiella (6), Proteus (2), Providencia (2), Serratia (6), and Streptococcus (14).

Figure 4

Non-metric multidimensional scaling (NMDS) of Bray–Curtis dissimilarity for bacterial communities present among four kitchen sampling locations within predominantly low-income households (n = 10) by household (A) and sampling location (B), Houston, Texas, 2021. Beta diversity computations were conducted using the averaged relative abundances of taxa between replicate samples.

Figure 5

Food safety behaviors reported by respondent parents according to bacterial foodborne pathogen presence detected within predominantly low-income households (n = 10), Houston, Texas, 2021. Red color indicates that the respective reported food safety behavior was inappropriate. Green color indicates that the respective reported food safety behavior was appropriate. White color indicates that the food safety behavior was not applicable, or the survey question did not receive a response.