Development and validation of stages-of-change questions to assess consumers' readiness to use a food thermometer when cooking small cuts of meat.

Consumers' readiness to use a food thermometer when cooking small cuts of meat was assessed using Prochaska's Transtheoretical Model of Behavior Change. Face, content, and concurrent validity were assessed by peer review, cognitive interviews, and mail surveys. The self-administered mail survey was sent to two groups of Washington and Idaho residents: 1,000 randomly selected consumers (41% return rate), and 231 employees and volunteers of Cooperative Extension involved in food and nutrition education (60% return rate). Two-stage classification questions were compared with a behavior question about thermometer use, and validated using Cronbach's if-item-deleted option for alpha. Concurrent validity was assessed using cross-tabulation chi2 test. The detailed classification question more accurately classified respondents in both Consumer and Extension groups. Cronbach's alpha of the detailed question with the behavior question showed a consistency level of alpha=.73 compared to alpha=.35 for the simple question format. As expected, Consumer and Extension groups differed significantly in their stages of change (P<0.0001), verifying concurrent validity. We recommend use of the detailed classification question when staging persons related to food thermometer use. The process used for development and testing can be used to refine instruments for use in other types of interventions.

Educational intervention enhances consumers' readiness to adopt food thermometer use when cooking small cuts of meat: an application of the transtheoretical model.

An intervention to promote use of food thermometers when cooking small cuts of meat was conducted using the Transtheoretical Model. Objectives were to (i) increase use of food thermometers by home food preparers, (ii) improve consumers' attitudes regarding use of a food thermometer, and (iii) examine relationships between stages of change and decisional balance, self-efficacy, and processes of change. A randomly selected group of residents of Washington and Idaho (n = 2,500) were invited to participate in the research; 295 persons completed all phases of the multistep intervention. Following the intervention program, there was a significant increase in food thermometer use when cooking small cuts of meat (P < 0.01); those persons classified in action and maintenance stages increased from 9 to 34%. Ownership of thermometers also significantly increased (P < 0.05). The three constructs related to the Transtheoretical Model that were used in the study (decisional balance, self-efficacy, and processes of change) were very useful for examining differences among people at different stages of change because the responses for each set of questions differed positively and significantly (P < 0.01) as stages of change classifications advanced from precontemplation (no interest in thermometer use) to action and maintenance (individuals who use food thermometers). Additional educational campaigns designed to increase use of food thermometers are needed. Because most consumers are currently in the precontemplation stage, food thermometer campaigns will be most effective when they are focused on raising awareness of the food safety risks and the benefits of using food thermometers when cooking small cuts of meat.

Evaluation of consumer-style cooking methods for reduction of Escherichia coli O157:H7 in ground beef.

The objective of this study was to evaluate the thermal inactivation of Escherichia coli O157:H7 in ground beef cooked to an internal temperature of 71.1 degrees C (160 degrees F) under conditions simulating consumer-style cooking methods. To compare a double-sided grill (DSG) with a single-sided grill (SSG), two different cooking methods were used for the SSG: for the one-turnover (OT-SSG) method, a patty was turned once when the internal temperature reached 40 degrees C, and for the multiturnover (MT-SSG) method, a patty was turned every 30 s. Patties (100 g, n = 9) inoculated with a five-strain mixture of E. coli O157: H7 at a concentration of 10(7) CFU/g were cooked until all three temperature readings (for two sides and the center) for a patty were 71.1 degrees C. The surviving E. coli O157:H7 cells were enumerated on sorbitol MacConkey (SMAC) agar and on phenol red agar base with 1% sorbitol (SPRAB). The order of the cooking methods with regard to the cooking time required for the patty to reach 71.1 degrees C was as follows: DSG (2.7 min) < MT-SSG (6.6 min) < OT-SSG (10.9 min). The more rapid, higher-temperature cooking method was more effective (P < 0.01) in destroying E. coli O157:H7 in ground beef. E. coli O157:H7 reduction levels were clearly differentiated among treatments as follows: OT-SSG (4.7 log10 CFU/g) < MT-SSG (5.6 log10 CFU/g) < DSG (6.9 log10 CFU/g). Significantly larger numbers of E. coil O157:H7 were observed on SPRAB than on SMAC agar. To confirm the safety of ground beef cooked to 71.1 degrees C, additional patties (100 g, n = 9) inoculated with lower concentrations of E. coli O157:H7 (10(3) to 10(4) CFU/g) were tested. The ground beef cooked by the OT-SSG method resulted in two (22%) of nine samples testing positive after enrichment, whereas no E. coli O157:H7 was found for samples cooked by the MT-SSG and DSG methods. Our findings suggest that consumers should be advised to either cook ground beef patties in a grill that cooks the top and the bottom of the patty at the same time or turn patties frequently (every 30 s) when cooking on a grill that cooks on only one side.