Food Safety Consumer Research Project: Meal Preparation Experiment Related to Poultry Washing

Executive Summary | August 2019

1

Food Safety Consumer Research Project: 

Meal Preparation Experiment Related to Poultry Washing 

Executive Summary 

August 2019

The Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture (USDA) contracted 

with RTI International and its subcontractor North Carolina State University (NCSU) to conduct meal 

preparation experiments to evaluate consumer food handling behaviors in a test kitchen. The research 

team is conducting five separate iterations of the study to address a specific consumer behavior and to 

determine the effectiveness of a behavior change intervention. The meal preparation experiments are 

part of a larger 5-year annual study that also includes focus groups (two iterations) and web surveys 

(two iterations). This report describes the results of the second iteration of the meal preparation 

experiment that examined consumers’ washing of poultry when preparing a meal of chicken thighs.

RTI and NCSU conducted the study in eight test kitchen facilities located in the Raleigh-Durham area of 

North Carolina and Lillington, North Carolina, a rural location, with individuals who self-reported 

washing or rinsing raw poultry when cooking at home. Three existing Office of Public Affairs and 

Consumer Education (OPACE) food safety messages were delivered to treatment group participants via 

email before their appointment; each message was sent twice as part of the signature line of the NCSU 

scheduling team. One message focused on not washing poultry before cooking to avoid crosscontamination and included a link to an FSIS YouTube video (with screenshot of video), one message 

recommended using separate cutting boards for raw and ready-to-eat foods (with graphic), and one 

message featured an FSIS “Clean” infographic with information on not washing poultry and the 

messages to wash hands for 20 seconds with soap and warm water and to wash kitchen surfaces and 

equipment (e.g., utensils). Control group participants emails did not include the intervention messages. 

In each test kitchen, six cameras recorded participants’ actions at various locations throughout the 

kitchen and recorded the meal preparation from beginning to end. Participants in the control and 

treatment groups were observed while cooking chicken thighs (spiked with harmless traceable 

nonpathogenic E. coli strain DH-5 alpha) and preparing a mixed green salad recipe to determine whether 

they washed their poultry, the extent of cross-contamination throughout the kitchen, and whether they 

adhered to other food safety behaviors throughout meal preparation. Following meal preparation and 

participants’ cleaning and/or sanitizing of the kitchen, the study team collected microbiological samples 

from surfaces and lettuce and analyzed the samples for prevalence and level of DH-5 alpha. 

Participants participated in a post-observation interview to collect information on their usual food 

preparation practices and possible predictors of behavior change. A total of 300 people participated in 

the study (158 control, 142 treatment).

Key Findings

The key findings from the study are summarized below:

Poultry Washing

o The food safety messages in the emails effectively encouraged participants not to wash raw 

chicken thighs before cooking: 93 percent of treatment group participants did not wash the 

chicken compared with 39 percent for the control group. 
Food Safety Consumer Research Project: Meal Preparation Experiment Related to Poultry Washing

Executive Summary | August 2019

2

o When washing the chicken, most participants rinsed it in the sink rather than submerging it in 

the sink or container. Participants who wash chicken when preparing it at home reported that 

they did so to remove blood/slime (30 percent) or because that is how a family member does it 

(19 percent).

o In the post-observation interviews, 66 percent of participants stated that reading the email 

messages influenced their cooking behavior in the kitchen; of these participants, 40 percent

reported that their actions were influenced by learning new information about preparing 

poultry.

Handwashing 

o Proper handwashing was addressed in one of the email messages but did not influence 

participants’ handwashing practices. Among all handwashing events required before or during 

meal preparation, only 2 percent included all steps necessary to be considered an adequate 

handwashing event (defined by the Centers for Disease Control and Prevention’s recommended 

steps). 

o Comparing the results for Years 1 and 2, there were no significant differences in terms of 

handwashing events attempted and successful and unsuccessful handwashing attempts. As in 

Year 1, the most documented reason for not successfully washing hands was failing to rub hands 

with soap for at least 20 seconds.

Reasons for Unsuccessful Handwashing Attempts during Meal Preparation

Cleaning and Sanitizing Surfaces and Equipment

o The intervention did not appear to affect whether participants attempted cleaning and 

sanitizing when required or whether it was successful for the kitchen counter, the sink among 

poultry washers, and knives or cutting boards used to prepare chicken. There was not a 

significant difference in successful cleaning and sanitizing events between the control and 

treatment groups.

23%

16%

77%

1% 2% 2% 1%

21%

11%

70%

0% 2% 2% 1%

0%

20%

40%

60%

80%

100%

Did not

wet hands

Did not

use soap

Did not

rub hands for

20 seconds

Did not

rinse

Did not

dry

Dried, but

did NOT use

clean, one-use

towel

Undetermined

Control Treatment
Food Safety Consumer Research Project: Meal Preparation Experiment Related to Poultry Washing

Executive Summary | August 2019

3

o The use of the same cutting board for preparing the chicken and the salad was lower among 

treatment group participants compared with the control group, suggesting an intervention 

effect—one of the email messages advised using separate cutting boards for raw meat/poultry 

and RTE foods. 

Cleaning and Sanitizing Counters after Meal Preparation

Cross-contamination and Microbiological Analysis

o The lettuce from the prepared salad was found to be contaminated at a frequency of 26% and 

20% for poultry washers and nonwashers, respectively. Hand-facilitated cross-contamination is 

suspected to be an important factor in explaining this level of cross-contamination.

o High levels of the tracer E. coli strain DH-5 alpha detected in the sink and on the salad lettuce 

suggest that microbes harbored in the sink from chicken, packaging, or contaminated hands are 

a larger cause for concern than splashing contaminated chicken fluids onto the counter.

o As previously noted, there was no impact on cleaning and sanitizing or handwashing behaviors 

when comparing the control and treatment groups, but for non-poultry washers, participants in 

the control group were more likely to contaminate the salad than those in the treatment group, 

suggesting an intervention effect.

Prevalence of Surrogate Contamination and Level of Contamination for Locations in the Kitchen and

Salad Lettuce When Chicken Was Washed

Location

All 

Participants Control Treatment p valuea

Post-wash 

inner sink

Prevalence 

contaminated % (n)

60.32 (63) 59.65 (57) 66.67 (6) .7401

Level of contamination ± 

SD, log CFU/g (n)

4.49 ± 4.84 

(38)

4.49 ± 4.86 

(34)

4.47 ± 4.72 

(4)

.9938

19% 24%

78% 71%

3% 6%

0%

20%

40%

60%

80%

100%

Control Treatment

Did not attempt Unsuccessful Successful
Food Safety Consumer Research Project: Meal Preparation Experiment Related to Poultry Washing

Executive Summary | August 2019

4

Location

All 

Participants Control Treatment p valuea

Post-clean 

inner sink

Prevalence 

contaminated, % (n)

14.29 (63) 14.04 (57) 16.67 (6) .8621

Level of contamination ± 

SD, log CFU/g (n)

4.11 ± 4.55 

(9)

4.16 ± 4.58 

(8)

1.65 ± NA 

(1)

NA

Spice 

container

Prevalence 

contaminated % (n)

6.25 (96) 4.65 (86) 20.00 (10) .0590

Level of contamination 

(SD), log CFU/g (n)

2.23 ± 2.12 

(6)

2.07 ± 1.99 

(4)

2.45 ± 2.41 

(2)

.8449

Salad 

lettuce 

Prevalence 

contaminated % (n)

25.77 (97) 26.44 (87) 30.00 (10) .8108

Level of contamination 

(SD), log CFU/g (n)

3.09 ± 3.35 

(25)

3.05 ± 3.34 

(23)

3.39 ± 3.52 

(3)

.8703

Notes: 

A positive result was any colony that fluoresced under UV when grown on selective media.

(n) = number of samples used in the analysis; SD = standard deviation; NA = unable to calculate p value because of 

small number of observations

Prevalence of Surrogate Contamination and Level of Contamination for Locations in the Kitchen and 

Salad Lettuce When Chicken Was Not Washed

Location All Participants Control Treatment p valuea

Post-clean 

inner sink

Prevalence 

contaminated % (n)

5.11 (137) 6.98 (43) 4.26 (94) .5040

Level of 

contamination ± SD, 

log CFU/g (n)

3.09 ± 3.48 (7) 3.43 ± 3.66 (3) 2.11 ± 2.23 (4) .5757

Spice 

container

Prevalence 

contaminated % (n)

4.89 (184) 7.27 (55) 3.88 (129) .3305

Level of 

contamination ± SD, 

log CFU/g (n)

2.49 ± 2.57 (9) 1.93 ± 1.84 (4) 2.68 ± 2.63 (5) .6452

Salad 

lettuce

Prevalence 

contaminated % (n)

19.57 (184) 30.91 (55) 14.73 (129) .0115

Level of 

contamination ± SD, 

log CFU/g (n) 

4.86 ± 5.54 (36) 4.48 ± 5.03 (17) 5.04 ± 5.67 (19) .7570

Notes: 

A positive result was any colony that fluoresced under UV when grown on selective media.

(n) = number of samples used in the analysis; SD = standard deviation; NA = unable to calculate p value because of 

small number of observations
Food Safety Consumer Research Project: Meal Preparation Experiment Related to Poultry Washing

Executive Summary | August 2019

5

Thermometer Use

o Forty-seven percent of all participants used a food thermometer on at least one chicken thigh. 

There were no significant differences between the control and treatment groups.

o In the Year 1 study, 34% of participants in the control group used a thermometer on at least one 

turkey patty, while in Year 2, 44% of the control group used a thermometer on at least one 

chicken thigh. 

Implications for FSIS Outreach Efforts

Exposure to the email messages on risks of poultry washing encouraged participants not to wash raw 

poultry; however, more needs to be done to increase adherence to more nuanced recommended 

practices such as proper cleaning and sanitizing of kitchen surfaces and equipment and proper 

handwashing. Based on the study findings and previous work in the literature related to risk 

communication, we recommend that FSIS consider designing food safety messaging that:

o changes the frame of “don’t wash your poultry” messaging to focus on preventing 

contamination of sinks, where fruits and vegetables are often washed;

o clarifies that recommendations to not wash poultry include not rinsing as well; 

o emphasizes the importance of both cleaning and sanitizing;

o continues to emphasize handwashing and cross-contamination because improvements are 

needed in these areas;

o uses social media to reach a broad audience quickly; and

o emphasizes USDA’s role as a credible source of information.

There is a great deal more to learn about consumer attitudes and behaviors as they relate to food 

safety, in particular related to actions consumers take to prevent cross-contamination in the kitchen. 

Understanding these factors will help FSIS create more targeted messaging and incorporate everyday 

contexts into food safety communications.