Regulating Shallow Pan Cooling by State and Local Retail Food Programs
Nicklaus Koreen
Senior Health Inspector Minneapolis Health Department
Abstract
Improper cooling of cooked time/temperature control for safety (TCS) foods remains a significant contributing factor in Clostridium perfringens bacteria outbreaks, while ineffective cooling of cooked TCS foods remains a concern in the restaurant industry. Retail food inspectors find assessing cooling time/temperature parameters during routine inspections challenging. The language in the FDA Model Food Code around evaluating cooling methods is subjective, and therefore a clear roadmap is not provided for inspectors. This study reviewed Minneapolis Health Department risk factor data to identify how often inspectors evaluated cooling time/temperature parameters during routine restaurant inspections. Restaurant operators in the City of Minneapolis were surveyed regarding which cooling methods they utilize when cooling TCS foods. State retail food program managers were surveyed to discover what fill depth their inspectors advise operators to use when shallow pan cooling. Both groups were asked if there should be a standardized definition for “shallow” regarding the shallow pan cooling technique. The findings of this study suggest restaurant operators frequently utilize the shallow pan cooling method. State health departments throughout the country advise their retail operators on a variety of fill depths across jurisdictional lines ranging from two inches to four inches. Most restaurant operators surveyed support the defining of shallow as it pertains to shallow pan cooling, while the majority of state retail food program managers surveyed don’t support a prescriptive fill depth. The findings of this study support previous findings from Schaffner that retail food inspectors are unable to evaluate time/temperature cooling parameters during routine inspections, which emphasizes the need to more diligently evaluate the cooling methods utilized.
Key words: Shallow pan, cooling, retail food programs
Regulating Shallow Pan Cooling by State and Local Retail Food Programs
Background
The Centers for Disease Control and Prevention (CDC) estimates foodborne illness outbreaks involving Clostridium perfringens account for 10% of all foodborne illness (Olds 2013). Between 2014 and 2016 the CDC confirmed 251 foodborne illness outbreaks where C. perfringens was implicated as the outbreak pathogen. From 1961 to 1982 improper cooling was cited as the number one factor in C. perfringens outbreaks (Roberts et al 2013). Spore forming bacteria such as C. perfringens can survive the cooking process and regenerate vegetative cells as the temperature of their environment remains in the pathogen’s growth range making extended cooling time frames problematic (Schaffner et al., 2015). This risk is especially elevated in the retail food setting where process control points are not commonly monitored (Brown 2012).
The U.S. Food and Drug Administration (FDA) has not identified specific guidelines for operators or inspectors to verify whether cooling standards are being met, and limited information exists about which cooling methods will likely meet the FDA Model Food Code time/temperature requirements (Olds, 2013). Effective, rapid cooling of TCS foods in the retail food industry remains a challenge. In a 2018 FDA risk factor study, data suggests that more than 70% of full-service restaurants ineffectively cool their cooked foods (FDA, 2018). Academic research measuring the success of cooling in retail food service operations has concluded that rapid cooling is a challenge across the industry (Roberts et al, 2013).
Retail food inspections cover many different aspects of food safety, evaluating both risk factors and good retail practices over the course of a single inspection, whereas, cooling of cooked TCS foods takes place over many hours making its evaluation during an inspection very challenging (Schaffner et al, 2015). Retail food inspectors often must rely upon verbal conversation with a restaurant operator to verify if its cooling methods are sufficient to rapidly cool cooked TCS foods. This conversation has the unintended consequence of operators reporting socially desirable outcomes and introduces reactivity bias (Schaffner et al, 2015). Current approaches both from the retail food industry and regulatory agencies need to change to reduce incidences of ineffective cooling and bacterial intoxications.
There is a scarcity in the academic research surrounding cooling methods in the retail food industry. Few studies have attempted to measure the success of cooling methods or further define each cooling method’s limitations (Olds, 2013). Previous academic research hasn’t focused on defining or establishing a threshold for “shallow” as it relates to an effective fill depth for foods while cooling. Previous research has compared the successful cooling of foods filled to depths less than or greater than 3 inches. While this research has concluded that cooling of food filled in pans at depths greater than 3 inches are less successful at meeting FDA minimum time/temperature requirements; the research has not compared fill depths between 2 and 3 inches (Schaffner et al, 2015). Cooling curve data obtained by the City of Minneapolis Health Department implies that fill depths of 2.5 inches or greater often is associated with cooling foods spending a dangerous amount of time in the Clostridium Perfringens growth range. This study attempts to identify whether there is a need to standardize a maximum allowable fill depth when regulating the shallow pan cooling method across the U.S.
Problem Statement
The impact of the interpretation of shallow pan cooling guidance in retail food service applications is unknown.
Research Questions
1. How often do retail food inspectors in the City of Minneapolis observe cooling of cooked TCS foods during a routine inspection?
2. What percentage of Minneapolis full-service restaurant operators utilize shallow pan cooling as one of their cooling methods?
3. What fill depths do state retail food program managers throughout the country recognize as safe?
4. How do Minneapolis full-service restaurant operators and state retail food program managers feel about a prescriptive depth as it pertains to shallow pan cooling?
Methodology
City of Minneapolis Health Department risk factor survey data over a two-year period from November 1, 2014 to October 31, 2016 was analyzed to understand how often City of Minneapolis health inspectors observed cooling of cooked TCS foods during a routine health inspection. Each of the routine inspections that was included in the dataset required inspectors to answer a checklist item, “proper cooling time and temperature.” The options that the inspector had to choose from included: in; out; not observed; or not applicable.
City of Minneapolis full-service restaurant operators were surveyed via email from September 2021 through December 2021 regarding the methods they used while cooling cooked TCS foods. Operators were given a list of cooling method options and were asked to identify which cooling methods they used allowing the operator to select all that apply. The options provided in the survey were: placing food into a shallow pan, using an ice wand, using an ice bath, mixing, adding ice to the food, placing food into a blast chiller, and other. The City of Minneapolis maintains a subscriber database with their NeoGov delivery system that is utilized for communication with their licensed retail food operators, and which was used for the electronic distribution of this survey. At the conclusion of the survey those operators were also asked if they would find it helpful for the FDA Model Food Code to specify a maximum allowable fill depth as it pertained to the application of cooling cooked foods within a shallow pan.
The Association of Food and Drug Officials (AFDO) maintains a list of retail state program managers throughout the country. All the state retail food program managers in the AFDO directory were surveyed via email from September 2021 through December 2021 regarding their state’s maximum allowable food fill depth as it pertained to cooling cooked foods with the shallow pan method in the retail food setting. State retail program managers were asked if they would find it helpful for the FDA Model Food Code to specify a standardized maximum allowable fill depth as it pertained to the application of cooling cooked foods within a shallow pan. The program managers were asked to explain why they felt the FDA should or shouldn’t specify a fill depth.
Branded resources such as fact sheets from state and local retail food programs, university extension services, and for-profit food safety educational institutions publications were analyzed to collect published language regarding maximum allowable shallow pan fill depths. When readily available information regarding a published specific allowable food fill depth was found, it was used to determine that jurisdiction’s interpretation of maximum allowable fill depth.
Results
Analyzing 2018 Minneapolis Health Department risk factor data revealed that health inspectors infrequently observed active cooling of TCS foods during routine health inspections. Between November 1, 2014, to October 31, 2016 the City of Minneapolis conducted 3,532 medium- and high-risk establishment routine inspections. For its risk factor study, the City of Minneapolis Health Department defined these establishments collectively as “restaurants.” Five hundred forty-four (544) of the included inspections resulting in the inspector marking not applicable (N/A) as it pertains to the cooling requirements being met, indicating those establishments don’t perform cooling of TCS foods. Two thousand nine hundred eighty-eight (2,988) inspections were remaining in the data set that included establishments that either performed cooling of cooked TCS foods or cooling of ambient TCS foods.
During 71.4% of routine restaurant inspections the inspector was unable to observe enough active cooling to determine if those establishments were following minimum time/temperature parameters. The frequency that cooling of cooked TCS foods was not observed is likely higher since this data set also includes observing ambient cooling as an opportunity to mark an observation for this checklist item. During 854 routine inspections in the data set an observation of cooling was made (either in or out). Of those 854 observations, 15.1% resulted in cooling being observed as out of compliance which accounted for the second highest ranked out of compliance risk factor in the study.
The survey that was sent to Minneapolis NeoGov subscribers received 127 responses of which 73 respondents self-identifying as Minneapolis restaurant operators or managers. Using an ice bath was the most frequently selected method used to cool TCS foods; 77.4% of respondents noted using this technique. Placing food into a shallow pan was utilized by 75.5% of respondents and was the second most utilized technique. Nearly 40% of respondents indicated that they placed either an ice wand or chill stick into the food while cooling, and almost 38% claimed to mix the food while it cools. Seventeen percent (17%) of respondents stated that they either used a blast chiller or placed ice directly into the food as an ingredient as one of their cooling methods.
Most of the NeoGov respondents (62.5%) indicated that they think the Minnesota Food Code should define shallow as it pertains to shallow pan cooling of cooked foods. Twenty-three-point two percent (23.2%) of the respondents felt unsure on whether the Minnesota Food Code should define shallow, while 14.3% of respondents felt the Minnesota Food Code should not define shallow.
Forty-eight (48) state retail food program managers were surveyed and 33 responded. Most state retail food program managers surveyed (21) indicated that their inspectors didn’t advise establishments on a specific maximum fill depth. The other 12 retail food program managers indicated that their inspectors did advise on a specific maximum fill depth, although some stated there was an acceptable range of depths. Three program managers indicated their inspectors advise a maximum of two inches, while three program mangers conversely indicated that they advised a maximum of four inches. The other respondents stated that their inspectors advise a maximum fill depth of three inches, a range of two to three inches or a range of three to four inches. No respondents reported advising a maximum fill depth of greater than four inches or less than two inches.
Fifty-seven-point six percent (57.6%) of program managers felt the FDA should not define shallow as it pertains to shallow pan cooling of cooked foods. Thirty-three-point three percent (33.3%) of the respondents thought the FDA should define shallow as it pertains to shallow pan cooling of cooked foods, and three respondents felt unsure on the FDA defining shallow. Twelve (12) program managers reported they felt other variables beyond fill depth impacted cooling enough that a specific maximum fill depth wouldn’t be appropriate, while five others reported they felt there should be flexibility within the FDA Model Food Code or that the FDA Model Food Code shouldn’t be too prescriptive. Additionally, five program managers reported that inspectors should focus on time and temperature of cooked foods, that the interpretation of shallow is clear enough, and that defining shallow may be costly to operators. Six program managers who stated that they supported a definition of shallow reported they felt shallow was either too subjective or too confusing. Four program managers reported that defining shallow would make regulating, enforcing, and educating easier for their inspectors.
Thirty-one (31) published fact sheets from state and local health departments, private organizations and university extension services were reviewed for advised maximum fill depths. Twenty-one (21) state and local health departments provide published fact sheets with 14 of them including a maximum fill depth. Allowable fill depths ranged from two to four inches almost equally amongst these sheets. Four university extension services fact sheets were analyzed with three of them specifying a maximum fill depth and all reporting a depth of two inches. Six private food safety organizations also published fact sheets regarding acceptable cooling methods while only two of them advertise a specific range of maximum allowable fill depths.
Conclusions
Retail food inspectors do not frequently observe active cooling of cooked TCS foods during their routine inspections. If Minneapolis serves as a representative sample of the country, then more than 70% of routine health inspections don’t include an evaluation of an establishment’s ability to meet the minimum time/temperature parameters for cooling cooked TCS foods. This risk factor remains out of compliance at a relatively high level when compared to other risk factors, while continuing to contribute to many illness outbreaks. Inspectors may impact behavior by focusing on the cooling method used by the establishment being inspected, rather than relying upon minimal to no time/temperature data.
Restaurant operators utilize a variety of cooling methods; one of the preferred methods is placing food into a shallow pan filled to a specific depth. Compared to the other methods being utilized by restaurant operators, this method represents one of the easier methods to evaluate during a routine inspection. This method is less dependent upon interventions during the process such as changing ice, replacing an ice wand, determining number of mixes and at what intervals, and changing the pan. If the inspector conducting the inspection understands what fill depth is acceptable for this technique and can verify that the refrigerated unit is properly working, they have the diagnostic tools needed to intervene when needed.
There is significant disparity across jurisdictional lines regarding the maximum allowable fill depth for shallow pan cooling. Amongst retail food safety professionals there is not a consensus as to what the proper maximum fill depth should be. Many state retail food program managers have their inspectors advise up to 4 inches, while others do not advise above 2 inches. Rates of cooling likely vary significantly between foods that are filled to two inches compared to foods that are filled to four inches with everything else being equal. If retail food inspectors across the country are going to improve their evaluation of cooling methods and therefore cooling outcomes, they must understand what maximum fill depth is safe.
The majority of restaurant operators surveyed are in favor of a standardized definition for shallow as it pertains to shallow pan cooling. In contrast, the majority of state retail food program managers surveyed do not support standardizing the definition of shallow as it pertains to shallow pan cooling.
Recommendations
Future research should focus on exploring the relative impact of each variable incorporated into the cooling process such as ambient air temperature, pan material, mixing, presence of an ice wand, or ice bath. Convincing state retail program managers that there is a need to define maximum fill depth will require proof that fill depth is a significant variable in the cooling process, everything else being equal.
Future research also should focus on understanding what specific fill depth is safe with everything else being equal. Past research has highlighted that depths less than 3 inches are much safer than depths greater than 3 inches, therefore advising on fill depths greater than 3 inches as it pertains to the shallow pan method is ill advised. Better understanding the cooling rate outcomes at fill depths between two and three inches when utilizing the shallow pan technique should further illuminate what an appropriate fill depth may be.
Washington State Retail Food Code provides a road map on code language that should be considered during an upcoming Conference for Food Protection meeting. This code language provides an alternative to the time/temperature parameters outlined in their Food Code by cooling cooked foods in a shallow layer of 2 inches or less, uncovered, and inside cooling equipment, maintaining an ambient air temperature of 41°F or less (Washington Administrative Code, 2021).
Acknowledgments
I thank contributions that were made by Logan Ebeling with the FDA, William Kass and Leslie Foreman with the Minneapolis Health Department along with Nicole Heeden from Minnesota Department of Health and my IFPTI colleagues, mentors, and staff. I also thank the restaurant operators and managers along with state retail food managers who participated in this study.
References
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Author Note
Nicklaus Koreen, Senior Health Inspector
Minneapolis Health Department
This research was conducted as part of the International Food Protection Training Institute’s Fellowship in Food Protection, Cohort X.
Correspondence concerning this article should be addressed to:
Nicklaus Koreen Minneapolis Health Department, 505 4th Avenue South, Room 520, Minneapolis, MN 55415
Nicklaus.Koreen@minneapolismn.gov
Funding for the IFPTI Fellowship in Food Protection Program was made possible by the Association of Food and Drug Officials.