Food and Nutrition Sciences, 2013, 4, 735-740
http://dx.doi.org/10.4236/fns.2013.47094 Published Online July 2013 (http://www.scirp.org/journal/fns)
Efficacy of Cooling Beef Taco Meat and Steamed Rice in
United States School Foodservice Operations*
David A. Olds1#, Kevin R. Roberts2, Kevin L. Sauer2, Jeannie Sneed2, Carol W. Shanklin3
1Department of Family and Consumer Sciences, Bradley University, Peoria, USA; 2The Center of Excellence for Food Safety Re-
search in Child Nutrition Programs, Department of Hospitality Management and Dietetics, Kansas State University, Manhattan, USA;
3Graduate School & the Center of Excellence for Food Safety Research in Child Nutrition Programs, Department of Hospitality
Management and Dietetics, Kansas State University, Manhattan, USA.
Received May 9th, 2013; revised June 9th, 2013; accepted June 16th, 2013
Copyright © 2013 David A. Olds et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Food is frequently cooked, cooled and reheated for service at a later time in schools and other foodservice op erations in
the United States [US]. Inadequate cooling of food has been associated with foodborne illness. The purpose of this
study was to determine if practices commonly used in school foodservice to cool beef taco meat and steamed rice would
meet US Food and Drug Administration [FDA] 2009 Food Code standards. Prepared products cooled at 5.08 cm and
7.62 cm depths in stainless steel counter pans were placed uncovered in a walk-in refrigerator, a walk-in freezer (beef
taco meat only), and a walk-in refrigerator with an ice water bath. Data were analyzed using descriptive statistics, in-
cluding mean times and temperatures, with standard deviations. Cooling beef taco meat in a walk-in freezer at a depth
of two inches and cooling steamed rice in a walk-in refrigerator at a depth of two inches with an ice water bath were the
only methods that met both FDA Food Code time and temperature standards. Results suggest that challenges and risks
exist with common methods used to cool food, especially if food volume is not reduced before cooling. Specific proto-
cols for cooling procedures based on types of food and equipment are needed. These findings and recommendations are
important for foodservice professionals who oversee food services and cooling practices in schools and other opera-
tions.
Keywords: Cooling; Schools; Foodservice; FDA; Food Code
1. Introduction
Approximately 12.1 million children are served breakfast
in schools each day [1] and over 31 million children are
served daily in the United States [US] National School
Lunch Program [2]. Due to the large numbers of children
served, food safety is paramount. To improve food safety,
the Child Nutrition and WIC [Women, Infants, and Chil-
dren] Reauthorization Act of 2004 required all schools to
have a food safety program based on Hazard Analysis
Critical Control Point [HACCP] principles [3].
When planning food safety programs, school foodser-
vice directors identified cooling as a potential critical
control point that needed attention. Between 1961 and
1982, inadequate cooling of food was the leading con-
tributing factor in 1918 cases of C. perfringens food-
borne illness outbreaks in the US [4]. The Centers for
Disease Control and Prevention [CDC] estimated that C.
perfringens bacteria, a bacteria often associated with im-
proper food temperatures, accounted for 10% of the 9.4
million cases of foodborne illness that occur annually in
the US [5]. The US General Accounting Office [6] re-
ported 447,483 cases of foodborne illness and 15,831
foodborne outbreaks be tween 1973 and 199 9, resu lting in
20,119 hospitalizations and 457 fatalities. From 1973 to
1997, 604 foodborne disease outbreaks were reported in
US schools, a median of 25 per year [7]. From 1990 to
1999, improper cooling was identified in five of 19 out-
breaks in school foodservice operations [6]. Inadequate
or “slow” cooling of food prepared on school premises
was ranked third in the top 10 reportedcontributingfac-
torsin16of 298 school-associated foodborne outbreaks
from 1998-2006 [8].
Krishnamurthy and Sneed [9] reported that 78% of
surveyed school f oodservice directors cooled leftovers to
*Authors declare no conflict of int erest.
#Corresponding author.

Efficacy of Cooling Beef Taco Meat and Steamed Rice in United States School Foodservice Operations 736
reheat and serve at another meal. Foods often cooled in
more than half of all schools included taco meat, turkey
(whole or roasts), and ch ili. Cooling most often was done
in walk-in refrigerators or walk-in freezers, and few fa-
cilities (8%) had blast chillers to speed the cooling proc-
ess. The majority of schools did not monitor product
temperatures during the cooling process. These findings
in schools are consistent with a recent study that found
that many restaurants do not verify cooling, do not moni-
tor time and temperature during cooling, and do not cali-
brate thermometers [10].
Cooling standards in the 2009 US Food and Drug Ad-
ministration [FDA] Food Code specify that cooked po-
tentially hazardous food shall be cooled within two hours
from 57.2˚C to 21.1˚C and within a total of six hours
from 57.2˚C to 5˚C or less [11]. The FDA considers
cooling to be a critical control point, “a point or proce-
dure in a specific food system where loss of control may
result in an unacceptable health risk” [11]. The 2009
FDA Food Code outlines acceptable cooling methods
based upon the type of food product to be cooled. These
cooling methods include placing food in shallow pans,
portioning food into thinner or smaller amounts, em-
ploying the use of specialized equipment to cool food
rapidly, stirring food in a container placed in an ice water
bath, utilizing containers that allow heat transfer, adding
ice to the food product, or other methods that facilitate
the cooling process [11]. The 2009 FDA Food Code
identifies methods used to meet cooling standards, but it
does not specify procedures for monitoring cooling or
provide guidelines for foodservice operators or inspec-
tors to verify if cooling standards are being met. Snyder
and Labalestra [12] stated that health departments have
not conducted cooling studies to verify the FDA cooling
standard in retail foodservice.
Previous research has established that challenges exist
to achieving FDA Food Code standards for cooling bulk
foods [12-15]. Research by Roberts et al. [13] examined
the efficacy of various cooling methods for liquid foods.
When comparing 5.08 cm and 7.62 cm depths of chili
and tomato sauce cooled in a walk-in refrigerator and
freezer, only products cooled at a 5.08 cm depth in a
freezer met FDA Food Code standards. The use of an ice
water bath decreased the initial cooling time of products
in a refrigerator, but the ice water bath was not changed
during the cooling process because typical school cooling
processes were being replicated. Although rapid cooling
of food is a known preventative measure to outbreaks of
foodborne illness, limited in formation exists about which
cooling methods meet FDA Food Code standards in
foodservice operations.
The purpose of this study was to determine if cooling
practices commonly used in school foodservice opera-
tions in the US to cool beef taco meat and rice would
meet FDA Food Code standards. Cooling practices ex-
amined included 5.08 cm and 7.62 cm depths of products
cooled in a walk-in refrigerator, walk-in freezer, and an
ice water bath combined with the walk-in refrigerator.
2. Methodology
2.1. Sample
United States Department of Agriculture [USDA] recipes
for schools, available online on the National Food service
Management Institute’s website [16], were used to pre-
pare two products: “Beef or Pork Taco”, USDA Recipe
D-13 (hereafter referred to as beef taco meat); and “ Coo k-
ing Rice”, USDA Recipe B-03 (hereafter referred to as
steamed rice). Beef taco meat and steamed rice represent
two food items that are prepared and cooled in the Na-
tional School Lunch Program [9]. Beef taco meat was
prepared in a stand ard steam-jacketed kettle an d steamed
rice was prepared in a standard convection steamer. Both
pieces of equipment are often used in school foodservice.
2.2. Cooling Procedures
Three replications w ere conducted for each cooling m e t h od
tested and three identically prepared and portioned food
product samples were used in each replication. The mean
cooling curves for each method and product tested were
determined. Prior studies demonstrated that covered food
products cooled slower than uncovered products [14,17].
Based on these findings, all food products tested were
left uncovered during cooling.
Table 1 outlines the cooling methods. Cooling times
and temperatures were logged at one minute intervals
during testing using Comark RF512 wireless temperature
transmitters (Comark Instruments, Beaverton, Oregon,
USA) in conjunction with a Comark RF500A wireless
monitoring gateway. A Comark RFAX100D thermistor
was fixed in the geometric center of food products tested
in 15.08 cm × 50.8 cm stainless steel pans. Probes were
fixed at 2.54 cm depths for food products tested at 5.08
cm product depths and at 3.81 cm depths for food prod-
ucts tested at 7.62 cm depths.
Prior to each replication, food products were prepared
and portioned identically. An insert pan containing an ice
water bath was used for replicates using the ice water
bath method. For ice water bath replicates, pans of food
product were lowered into insert pans (15.08 cm × 50.8
cm × 10.16 cm insert pans and 15.08 cm × 50.8 cm ×
15.24 cm insert pans for 5.08 cm and 7.62 cm cooling
methods, respectively) containing ice water (2:1 cubed
ice to cold tap water ratio), which contacted the bottom
and sides of the hot pans completely. Immediately fol-
lowing ice water bath insertion, replicates were placed in
a walk-in refrigerator for the remainder of the cooling

Efficacy of Cooling Beef Taco Meat and Steamed Rice in United States School Foodservice Operations 737
Table 1. Mean cooling times for beef taco meat and steamed rice using differing product depths and cooling methods.
Mean Cooling Time (hr:min) ± SD1
Food Product Product Depth Cooling Method 57.2˚C - 21.1˚C 57.2˚C - 5˚C
Beef Taco Meat 5.08 cm Walk-in freezer 1:47 ± 0:14 3:19 ± 0:24
Beef Taco Meat 5.08 cm Ice water bath in walk-in re frigerator 1:05 ± 0:06 7:30 ± 1:34
Beef Taco Meat 5.08 cm Walk-in refrigerator 3:01 ± 0:18 9:19 ± 1:01
Beef Taco Meat 7.62 cm Walk-in freezer 3:04 ± 0:19 5:22 ± 0:31
Beef Taco Meat 7.62 cm Ice water bath in walk-in ref rigerator 3:00 ± 0:17 15:48 ± 1:08
Beef Taco Meat 7.62 cm Walk-in ref rigerator 4:55 ± 0:14 15:24 ± 0:34
Steamed Rice2 5.08 cm Ice water bath in walk-in refrigerator 1:04 ± 0:05 3:04 ± 0:13
Steamed Rice 5.08 cm Walk-in refrigerator 3:18 ± 0:17 9:55 ± 0:53
Steamed Rice 7.62 cm Ice water bath i n walk-in refrigerator 2:02 ± 0:11 7:11 ± 1:15
Steamed Rice 7.62 cm Walk-in refrigerator 4:32 ± 0:18 13:37 ± 0:40
FDA 2009 FOOD CO DE COOLING STANDARDS3 2:00 6:00
1Standard deviation; 2Steamed rice was not tested in a walk-in freezer because this method is not commonly used in United States [US] school foodservice
operations; 3US Food and Drug Administration [FDA].
process. The ice water bath was not replaced during the
cooling process to simulate food handling procedures
previously observed in foodservice operations [18]. For
each replication, a maximum of four pans was placed in
the walk-in refrigerator or walk-in freezer during testing.
Following placement of food products into the walk-in
refrigerator/freezer, doors were securely locked and re-
mained closed until the cooling process had co ncluded.
3. Results and Discussion
Average cooling curves for beef taco meat and steamed
rice cooling methods are shown in Figures 1 and 2, re-
spectively. The only cooling method for the beef taco
meat that met both FDA standards (food product cooled
from 57.2˚C to 21.1˚C within two hours and 57.2˚C to
5˚C within a total of six hours) was when the product
was at a 5.08 cm depth and cooled in a walk-in freezer.
The only steamed rice method that met both FDA stan-
dards was when the product was cooled in an ice water
bath placed in a walk-in refrigerator at a 5.08 cm product
depth. Interestingly, the steamed rice cooled at a 5.08 cm
depth in an ice water bath met FDA standards while beef
taco meat cooled using the same method did not, illus-
trating that the physical nature of the product being
cooled impacts the cooling process. Steamed rice was not
tested in a walk-in freezer because this cooling method is
not commonly used in foodservice operations. It is rec-
ommended that steamed rice be cooled rapidly at a 5.08
cm depth or less using an ice water bath in a walk-in re-
frigerator to ensure that FDA standards are met.
Beef taco meat cooled using an ice water bath in the
walk-in refrigerator at a 5.08 cm depth met the first FDA
2009 Food Code standard (57.2˚C to 21.1˚C within two
hours), but failed to cool from 57.2˚C to 5˚C within a
total of six hours. Beef taco meat cooled in the walk-in
freezer at a 7.62 cm depth failed to meet the first FDA
standard of 57.2˚C to 21.1˚C within two hours, but did
cool from 57.2˚C to 5˚C within the required six hours.
Neither food product cooled within the recommended
FDA standards using the walk-in refrigerator or the ice
water bath in the walk-in refrigerator at 7.62 cm depths.
For all cooling methods, each food product required a
longer cooling time at 7.62 cm depths than at 5.08 cm
depths. None of the 7.62 cm cooling methods tested on
either food product met both FDA 2009 Food Code time
and temperature cooling standards. The method taking
the longest time to cool was the beef taco meat in an ice
water bath in a walk-in refrigerator at a 7.62 cm depth.
This product required longer than the same 7.62 cm
depth of beef taco meat in a walk-in refrigerator without
the ice water bath. The use of an ice water bath did in-
crease the cooling rate of beef taco meat from 57.2˚C to
21.1˚C, however, once the ice had melted, the additional
volume of warmed water inhibited rapid cooling com-
pared to the same product tested in the walk-in refrigera-
tor without an ice water bath at the same 7.62 cm depth.
Ice water baths speed the cooling process, but if they are
not changed once the ice has melted, it can actually in-
crease the overall cooling time. This study was designed
to simulate practices in schools, where employees leave
work after food production has concluded, thus being
unable to actively cool or monitor food products. There-
fore, ice water bath insert pans were not changed and
remained in place throughout all ice water bath replica-
tions.
4. Conclusions
Results show that cooling food properly is difficult and
may pose a food safety risk, especially if the volume of
food is not greatly reduced before cooling. Previous

Efficacy of Cooling Beef Taco Meat and Steamed Rice in United States School Foodservice Operations 738
Figure 1. Cooling curves for cooling beef taco meat.
Figure 2. Cooling curves for cooling steamed rice.

Efficacy of Cooling Beef Taco Meat and Steamed Rice in United States School Foodservice Operations 739
research demonstrated that blast chillers, which use for-
ced air, can effectively cool foods to FDA 2009 Food
Code standards [15]. However, blast chillers are expen-
sive and the financial resources may not be available in
many school foodservice operations to purchase them
even though the need for rapid cooling equipment exists.
This is supported by findings of Krishnamurthy and
Sneed [9] who surveyed 411 school foodservice direc-
tors/managers and found that only 8% of those opera-
tions had blast chillers available.
Foodservice operations require economical methods to
safely cool a wide variety of foods. Managers faced with
limited financial resources rely on refrigerators, freezers,
or ice water baths as practical means to safely cool food
products of 5.08 cm depths or less. However, freezers
may not be suitable if there is insufficient time to reheat
frozen food in time for service following cooling. As
shown in this study, ice water baths are suitable for po-
rous foods, such as rice, but are not suitable for denser
foods that do not permit cool air to penetrate the food
product and promote heat transfer. School foodservice
personnel may not distinguish between products that
should be cooled with ice water baths versus other
methods. Cooling foods in freezers may pose a challenge
if adequate space do es not exist to accommod ate cooling
along with regular and safe storage of frozen food prod-
ucts.
Specific recommendations for cooling procedures bas ed
on specific types of food and equipment should be de-
veloped and shared with foodservice managers in all
types of foodservice operations. These managers need to
monitor cooling times and temperatures to ensure that
cooling practices are effective for their operation based
on food, equipment, load of the cooling unit, and other
factors that influence cooling.
Future research should further explore the recom-
mended cooling methods in the FDA 2009 Food Code.
Specific instructions, based on sound science and re-
search, should be provided to foodservice operators who
wish to cool large amounts of food product. For example,
the current code recommends cooling food in an ice wa-
ter bath while stirring. However, specific information
about how often the product should be stirred and the
maximum depth needed to cool the food properly should
also be provided.
FDA Food Code standards for time and temperature
could be validated for microbiological growth of patho-
gens in environments that more closely simulate food
production in school foodservice operations. This study
found that barriers exist to proper food cooling even un-
der best-case scenarios. Further research is suggested to
determine which cooling methods could be effectively
implemented in foodservice operations, while also meet-
ing FDA 2009 Food Code standards to cool cooked po-
tentially hazardous food. Recommended cooling proce-
dures should be added to the USDA standardized recipes
and to policy and procedures manuals within each school
and/or district.
Results of this study can be applied to any foodservice
operation. Food service professionals in restaurants, medi-
cal centers, long-term care and assisted living facilities,
and college and universities can implement recommen-
dations to improve cooling in those operations.
5. Acknowledgements
This research project was conducted at Kansas State
University and was federally funded, in part, by the US
Department of Agriculture [USDA]. This research does
not necessarily reflect the views or policies of the USDA,
nor do mentions of organizations, commercial products,
or trade names within this publication suggest or imply
endorsement by the United States Government.
REFERENCES
[1] United States Department of Agriculture Food and Nutri-
tion Service, “The School Breakfast Program,” 2013.
http://www.fns.usda.gov/cnd/breakfast/AboutBFast/SBPF
actSheet.pdf
[2] United States Department of Agriculture Food and Nutri-
tion Service, “National School Lunch Program,” 2013.
http://www.fns.usda.gov/cnd/lunch/aboutlunch/NSLPFact
Sheet.pdf
[3] United States Department of Agriculture Food and Nutri-
tion Service, “The Child Nutrition and WIC Reauthoriza-
tion Act of 2004. Public Law 108-265, Section 111,”
2004.
http://www.fns.usda.gov/cnd/governance/legislation/histo
rical/pl_108-265.pdf
[4] F. L. Bryan, “Risks of Practices, Procedures, and Proc-
esses that Lead to Outbreaks of Foodborne Diseases,”
Journal of Food Protection, Vol. 51, No. 8, 1988, pp.
663-673.
[5] E. Scallan, R. M. Hoekstra, F. J. Angulo, R. V. Tauxe, M.
A. Widdowson, S. L. Roy, J. L. Jones and P. M. Griffin,
“Foodborne Illness Acquired in the United States—Major
Pathogens,” Emerging Infectious Diseases, Vol. 17, No. 1,
2011, pp. 7-15. doi:10.3201/eid1701.09-1101p1
[6] US General Accounting Office, “GAO: School Meal
Programs: Few Outbreaks of Foodborne Illness Reported,
but Opportunities Exist to Enhance Outbreak Data and
Food Safety Practices,” 2003.
http://www.gao.gov/products/GAO-03-530
[7] N. A. Daniels, L. Mackinnon, S. M. Rowe, N. H. Bean, P.
M. Griffin and P. S. Mead, “Foodborne Disease Outbreaks
in United States Schools,” Pediatric Infectious Disease
Journal, Vol. 21, No. 7, 2002, pp. 623-628.
doi:10.1097/00006454-200207000-00004
[8] L. T. Pogostin, S. Ayers, T. Gray, M. Nguyen, M. Lynch
and I. Williams, “School-Associated Foodborne Outbr eaks

Efficacy of Cooling Beef Taco Meat and Steamed Rice in United States School Foodservice Operations 740
in the United States—1998-2006,” The 4th Annual Out-
break Net Conference, Denver, 6 June 2008.
[9] K. Krishnamurthy and J. Sneed, “Cooling Practices Used
in School Foodservice,” Food Protection Trends, Vol. 31,
No. 12, 2011, pp. 828-833.
[10] L. G. Brown, D. Ripley, H. Blade, D. Reiman, K. Ever-
stine, D. Nicholas, J. Egan, N. Koktavy and D. N. Quil-
liam, “Restaurant Food Cooling Practices,” Journal of
Food Protection, Vol. 75, No. 12, 2012, pp. 2172-2178.
doi:10.4315/0362-028X.JFP-12-256
[11] US Food and Drug Administration, “FDA: Food Code
2009,” 2009.
http://www.fda.gov/Food/FoodSafety/RetailFoodProtecti
on/FoodCode/FoodCode2009/
[12] O. P. Snyder and J. A. Labalestra, “Comparison of the
Bimetallic Coil Thermometer and Thermocouple for
Validating Food Cooling,” Food Protection Trends, Vol.
24, No. 6, 2004, pp. 423-428.
[13] K. R. Roberts, D. A. Olds, C. Shanklin, K. Sauer and J.
Sneed, “Cooling of Foods in Retail Foodservice Opera-
tions,” Food Protection Trends, Vol. 33, No. 1, 2013, pp.
27-31.
[14] D. A. Olds, A. F. Mendonca, J. Sneed and B. Bisha, “In-
fluence of Four Retail Foodservice Cooling Methods on
the Behavior of Clostridium perfringens ATCC 10388 in
Turkey Roasts Following Heating to an Internal Tem-
perature of 74˚C,” Journal of Food Protection, Vol. 69,
No. 1, 2006, pp. 112-117.
[15] D. A. Olds and J. Sneed, “Cooling Rates of Chili Using
Refrigerator, Blast Chiller, and Chill Stick Cooling
Methods,” Journal of Child Nutrition & Management,
Vol. 29, No. 1, 2005.
http://docs.schoolnutrition.org/newsroom/jcnm/05spring/
[16] National Foodservice Management Institute, “NFSMI:
USDA Recipes for Schools,” 2013.
http://www.nfsmi.org/Templates/TemplateDefault.aspx?q
s=cElEPTEwMyZpc01ncj10cnVl
[17] Institute for Food Safety and Health, “USDA-FNS/FDA/
IFSH Study on Cooling of Foods in School Food Service
Operations, Final Report,” 2011.
[18] D. Henroid and J. Sneed, “Readiness to Implement Haz-
ard Analysis and Critical Control Point (HACCP) Sys-
tems in Iowa Schools,” Journal of the American Dietetic
Association, Vol. 104, No. 6, 2004, pp. 180-185.
doi:10.1016/j.jada.2003.11.009