1656 

Journal of Food Protection, Vol. 78, No. 9, 2015, Pages 1656–1663

doi:10.4315/0362-028X.JFP-15-101 

Microbiological Testing Results of Boneless and Ground Beef

Purchased for the National School Lunch Program, 2011 to 2014

DARIN R. DOERSCHER, TERRY L. LUTZ, STEPHEN J. WHISENANT, KERRY R. SMITH, CRAIG A. MORRIS, AND

CARL M. SCHROEDER* 

Livestock, Poultry, and Seed Program, Agricultural Marketing Service, U.S. Department of Agriculture, 1400 Independence Avenue,

Washington, D.C. 20250, USA

MS 15-101: Received 6 March 2015/Accepted 18 May 2015 

ABSTRACT

The Agricultural Marketing Service (AMS) purchases boneless and ground beef for distribution to recipients through federal 

nutrition assistance programs, including the National School Lunch Program, which represents 93% of the overall volume. 

Approximately every 2,000 lb (ca. 907 kg) of boneless beef and 10,000 lb (ca. 4,535 kg) of ground beef are designated a ‘‘lot’’

and tested for Escherichia coli O157:H7, Salmonella, standard plate count organisms (SPCs), E. coli, and coliforms. Any lot of 

beef positive for E. coli O157:H7 or for Salmonella, or any beef with concentrations of organisms exceeding critical limits for 

SPCs (100,000 CFU g 1

), E. coli (500 CFU g 1), or coliforms (1,000 CFU g 1) is rejected for purchase by AMS and must be 

diverted from federal nutrition assistance programs. From July 2011 through June 2014, 537,478,212 lb (ca. 243,795,996 kg) of 

boneless beef and 428,130,984 lb (ca. 194,196,932 kg) of ground beef were produced for federal nutrition assistance programs. 

Of the 230,359 boneless beef samples collected over this period, 82 (0.04%) were positive for E. coli O157:H7, 924 (0.40%) were 

positive for Salmonella, 222 (0.10%) exceeded the critical limit for SPCs, 69 (0.03%) exceeded the critical limit for E. coli, and 

123 (0.05%) exceeded the critical limit for coliforms. Of the 46,527 ground beef samples collected over this period, 30 (0.06%) 

were positive for E. coli O157:H7, 360 (0.77%) were positive for Salmonella, 20 (0.04%) exceeded the critical limit for SPCs, 22 

(0.05%) exceeded the critical limit for E. coli, and 17 (0.04%) exceeded the critical limit for coliforms. Cumulatively, these data 

suggest beef produced for the AMS National School Lunch Program is done so under an adequate food safety system, as 

indicated by the low percentage of lots that were pathogen positive or exceeded critical limits for indicator organisms. 

The U.S. Department of Agriculture (USDA) purchases 

food for various federal nutrition assistance programs, 

including the National School Lunch Program (NSLP). 

Purchases for the NSLP are done under authority of the 

Richard B. Russell National School Lunch Act. The food is 

provided by USDA to states for use in preparing school 

lunches. The amount of food provided to states is based on 

the number of lunches served to children at participating 

schools at reimbursement rates that vary by family economic 

need. In the aggregate, each day, food purchased through the 

NSLP is served to approximately 31 million schoolchildren 

in over 101,000 participating institutions (26). 

Beef—including fresh and frozen boneless and 

ground—is a staple of the NSLP. For example, during 

fscal year 2014, of the approximately 87 million lb (ca. 39 

million kg) of fresh and frozen boneless and ground beef 

purchased by the USDA Agricultural Marketing Service 

(AMS), approximately 82 million lb (ca. 37 million kg) were 

designated for the NSLP (4) (to convert pounds to 

kilograms, multiply by 0.45359237). Beef purchased by 

AMS is delivered to recipient states one of two ways. It is 

delivered raw, in which case it is cooked by kitchens in 

* Author for correspondence. Tel: 202-692-0342; Fax: 202-720-

1112; E-mail: carl.schroeder@ams.usda.gov.

individual school districts, or it is delivered cooked, having 

been cooked under federal inspection at a further processing 

facility. 

The AMS purchase specifcations for beef include 

domestic origin and harvest (slaughter), quality control and 

food safety, and animal handling and welfare requirements 

(3). For beef scheduled for delivery to states raw, AMS 

requires individual lots of beef (approximately 2,000 lb for 

boneless and approximately 10,000 lb for ground) be tested 

for the pathogens Escherichia coli O157:H7 and Salmonella, and for standard plate count organisms (SPCs), total 

coliforms, and E. coli as indicator organisms. AMS rejects 

for purchase any lot found positive for pathogens or 

exceeding the critical limits for SPCs (100,000 CFU g 1

), 

total coliforms (1,000 CFU g 1

), or E. coli (500 CFU g 1). 

In addition, indicator organism results from one out of every 

fve lots, selected at random, are used to calculate process 

capability values as a measure of an establishment’s overall 

process control, the results of which determine whether the 

establishment may continue producing beef for AMS (3). 

The same specifcations apply for beef scheduled for 

cooking at federally inspected further processing establishments during 2011 to 2013, with the exception of 2014, 

where boneless beef destined for this avenue of processing 

were no longer required to undergo pathogen testing. This 
J. Food Prot., Vol. 78, No. 9 NATIONAL SCHOOL LUNCH PROGRAM BEEF TESTING 1657 

change in requirement was a result of recommendations 

made by the National Academies National Research Council 

(NRC) (20) and the National Advisory Committee on 

Microbiological Criteria for Foods (NACMCF) (19). 

Results from AMS purchase specifcation microbiological testing are summarized and posted quarterly to the AMS 

Web site (1). AMS posts the results so that stakeholders and 

other interested parties may monitor the overall microbiological quality of beef produced for the NSLP. Given the 

number of children fed through the NSLP with public funds, 

it is important to make the data available to ensure program 

transparency. 

The purpose of this analysis is twofold. First, to 

describe in detail the microbiological results generated 

through AMS beef purchase specifcations for the most 

recent 4-year period. Second, to discuss the evolution of 

current purchase specifcations, including improvements 

made based on independent reviews by the NRC and 

NACMCF, and potential future revisions that may further 

strengthen the AMS beef purchase program. 

MATERIALS AND METHODS

Sample collection. All samples were collected by trained 

employees of AMS vendor establishments (2). Fresh (not frozen) 

samples were collected as described in the Food Safety and 

Inspection Service (FSIS) Directive 10,010.1 Revision 3 (28). For 

boneless beef, an individual sample representing the beef carcass 

exterior (3 in. long by 1 in. wide by 1/8 in. thick) was removed 

aseptically by knife from each of 70 individual pieces of beef 

trim, randomly chosen from each approximately 2,000-lb lot by 

the AMS vendor establishment employee. Sixty individual 

samples were aseptically transferred into a single Whirl-Pak 

bag (Nasco, Fort Atkinson, WI) and designated for testing for the 

presence of E. coli O157:H7, fve individual samples were 

aseptically transferred into a separate single Whirl-Pak bag and 

designated for testing for the presence of Salmonella, and fve 

individual samples were aseptically transferred into a separate 

single Whirl-Pak bag and designated for testing for the 

concentration of indicator organisms (SPCs, total coliforms, and 

E. coli). The bags were sealed and placed on prefrozen gel ice 

packs in insulated shipping containers. 

For ground beef, three samples were collected randomly by 

the AMS vendor establishment employee from each approximately 

10,000-lb lot: 325 g 6 10% (293 to 358 g) was collected for E.

coli O157:H7 testing; 25 g 6 10% (23 to 28 g) was collected for 

Salmonella testing; and 25 g 6 10% (23 to 28 g) was collected for 

indicator organism testing. (In 2014, FSIS increased the sample 

size of ground beef for Salmonella testing from 25 to 325 g. 

However, AMS did not require vendors to collect 325 g for 

Salmonella testing until 2015. Thus, all of the samples used to test 

for Salmonella in this study were 25 g.) Each sample was 

aseptically transferred to a separate prelabeled sterile Whirl-Pak 

bag and processed for shipping, as described previously for 

boneless beef trim. 

All samples collected by AMS vendor establishment 

employees were sent to an AMS-designated laboratory (ADL), as 

assigned by AMS. Establishment employees completed sample 

submission forms (which included tracking numbers, weight of 

product samples, lot numbers, and similar information) supplied by 

the ADL to the AMS vendor establishment. The sample 

submission forms were then placed with the samples inside the 

insulated shipping containers and sent overnight to the ADL. 

Sample receipt and processing. Upon receipt by the ADL, 

sample shipping containers and Whirl-Pak bags were examined to 

ensure they were intact. In addition, sample submission forms were 

examined to ensure they were fully and properly completed. If the 

integrity of the packaging was not confrmed, if there were signs of 

temperature abuse, or if the submission form was deemed 

incomplete or incorrect, the sample was discarded and a backup 

sample was requested from the AMS vendor. If packaging integrity 

and proper temperature were confrmed and the submission form 

deemed complete and correct, samples were then processed. 

AMS requires samples be processed according to methods 

described in the Microbiological Laboratory Guidebook (MLG) of 

the FSIS (27). For detecting E. coli O157:H7 in boneless beef and 

in ground beef, a sample (325 6 32.5 g) was placed into modifed 

tryptic soy broth (mTSB) at a ratio of 1:4 and incubated at 42 6

18C for 15 to 24 h. Following incubation, a 20-ll sample aliquot 

was used as template in the BAX System Real-Time PCR Assay 

(DuPont, Wilmington, DE) for E. coli O157:H7. Samples that 

tested BAX negative were reported as negative. For samples that 

tested BAX positive, culture confrmation was attempted by using 

the protocol described in Section 5.09 of the FSIS MLG (27). 

Culture-confrmed samples were reported as positive, and nonconfrmed samples were reported as negative. 

For detecting Salmonella in boneless beef, a sample (25 6

2.5 g) was placed into mTSB at a ratio of 1:4 and incubated at 42 

6 18C for 15 to 24 h. Following incubation, a 5-ll sample aliquot 

was used as template in the BAX System Real-Time PCR Assay 

for Salmonella. Samples that tested BAX negative were reported as 

negative. For samples that tested BAX positive, culture confrmation was attempted by using the protocol described in Section 4.08 

of the FSIS MLG (27). Culture-confrmed samples were reported 

as positive, and nonconfrmed samples were reported as negative. 

For detecting Salmonella in ground beef, a sample (25 6 0.5 

g) was placed into a Whirl-Pak or stomacher bag, 225 6 22.5 ml 

of buffered peptone water was added, the mixture was blended by 

vigorous shaking for 2 min, and incubated at 35 6 28C for 20 to 24 

h. Following incubation, 5 ll of sample was used as template in the 

BAX System Real-Time PCR Assay for Salmonella. Samples that 

tested BAX negative were reported as negative. For samples that 

tested BAX positive, culture confrmation was attempted by using 

the protocol described in Section 4.08 of the FSIS MLG (27). 

All Salmonella isolates recovered through the AMS testing 

program were sent by AMS ADLs to the FSIS Southeastern 

Laboratory in Athens, GA, where they were serotyped using the 

methods described by McQuiston et al. (18) and by Fitzgerald et al. 

(12). Serotyping and reporting of Salmonella isolates recovered 

began in January 2013 and has continued since. 

For detecting and quantifying SPCs, total coliforms, and E.

coli in boneless beef, protocols described in Section 3.02 of the 

FSIS MLG (27) were used. Twenty-fve grams of sample was 

placed into a sterile blender jar or bag, 450 ml of sterile 

Butterfeld’s phosphate diluent or buffered peptone water was 

added, and the sample was blended or shaken vigorously for 2 min. 

The resultant homogenate was serially diluted. SPCs were 

quantifed by using the petriflm method described in Subsection 

3.6.2 of the FSIS MLG (27). Total coliforms and E. coli were 

quantifed by using the method described in Subsection 3.7.2 of the 

FSIS MLG (27). 

Result reporting. Microbiological results were provided by 

the ADL to AMS through two routes. First, the ADL placed the 

results in a comma-separated value fle and transmitted the fle to 

AMS by uploading it to a Microsoft SQL database. Second, the 

ADL placed the results in a Microsoft Excel spreadsheet (Micro-
1658 DOERSCHER ET AL. J. Food Prot., Vol. 78, No. 9 

TABLE 1. Incidence of E. coli O157:H7 and Salmonella in boneless beef produced for AMS during school years 2011 to 2014a

Tonnage Lot count E. coli O157:H7 positiveb Salmonella positivec

School year lb % No. % No. % No. % 

2011 

2012 

2013 

2014 

Total 

172,185,015 

127,071,414 

122,071,614 

116,150,169 

537,478,212 

32.04 

23.64 

22.71 

21.61 

100.00 

49,217 

62,830 

60,802 

57,510 

230,359 

21.37 

27.27 

26.39 

24.97 

100.00 

6 

12 

41 

23 

82 

0.01 

0.02 

0.07 

0.04 

0.04 

96 

258 

300 

270 

924 

0.20 

0.41 

0.49 

0.47 

0.40 

a School year: July to June. All E. coli O157:H7–positive boneless beef and all Salmonella-positive boneless beef was rejected for purchase 

by AMS and thus not distributed to the National School Lunch Program or other federal nutrition assistance programs. To convert pounds 

to kilograms, multiply by 0.45359237. 

b E. coli O157:H7 critical limit: positive (þ) result 325 g 1

. c Salmonella critical limit: positive (þ) result 25 g 1

. 

soft Corporation, Redmond, WA) and transmitted the spreadsheet 

to AMS via electronic mail. Upon receipt of both data fles, AMS 

sought to reconcile the data in the fles. In the event of 

discrepancies, AMS worked with the ADL to identify the cause 

and resolve the discrepancy. The reason for this dual approach for 

transmitting data was to ensure data were delivered to AMS in a 

timely and accurate way so that AMS could make daily 

determinations about vendor eligibility (3). Serotype information 

was provided by electronic mail from FSIS to AMS quarterly. 

Data analysis. Microbiological test results were organized 

and summarized by using Microsoft Excel pivot table functions. 

Further analyses were done with Spotfre 6.5.0 (TIBCO Software 

Inc., Palo Alto, CA) to examine trends and anomalies in the data, 

including correlations between pathogen-positive samples and 

those in which indicator microorganisms exceeded critical limits. 

RESULTS

For the period July 2011 through June 2014, AMS 

purchased 537,478,212 lb of boneless beef. A total of 

230,359 lots of boneless beef (an average of 2,333 lb per lot) 

were tested for the presence of E. coli O157:H7 and 

Salmonella. Eighty-two (0.04%) of the lots were positive for 

E. coli O157:H7 and 924 (0.40%) of the lots were positive 

for Salmonella (Table 1). The lots of boneless beef were also 

tested for the presence and concentration of SPC organisms, 

total coliforms, and E. coli. Two hundred twenty-two 

(0.10%) of the lots contained SPC concentrations greater 

than the AMS purchase specifcation critical limit of 

100,000 CFU g 1

, 123 (0.05%) of the lots contained total 

coliform concentrations greater than the AMS purchase 

specifcation critical limit of 1,000 CFU g 1

, and 69 (,0.03) 

contained E. coli concentrations greater than the AMS 

purchase specifcation critical limit of 500 CFU g 1 (Table 

2). 

Also for the period July 2011 through June 2014, AMS 

purchased 428,130,984 lb of ground beef, all of which was 

derived from the boneless beef purchased by AMS during 

the same period. A total of 46,527 lots of ground beef (an 

average of 9,202 lb per lot) were tested for the presence of E.

coli O157:H7 and Salmonella. Thirty (0.06%) of the lots 

were positive for E. coli O157:H7, and 360 (0.77%) of the 

lots were positive for Salmonella (Table 3). Twenty 

(,0.04%) of the lots contained SPC concentrations greater 

than the AMS purchase specifcation critical limit of 

100,000 CFU g 1

, 17 (,0.04%) of the lots contained total 

coliform concentrations greater than the AMS purchase 

specifcation critical limit of 1,000 CFU g 1

, and 22 (0.05%) 

contained E. coli concentrations greater than the AMS 

purchase specifcation critical limit of 500 CFU g 1 (Table 

4). 

TABLE 2. Incidence of indicator organism concentrations exceeding critical limits in boneless beef produced for AMS during school

years 2011 to 2014a

Tonnage Lot count 

SPC critical 

limit exceededb

Coliform critical 

limit exceededc

E. coli critical 

limit exceededd

School year lb % No. % No. % No. % No. % 

2011 

2012 

2013 

2014 

Total 

172,185,015 

127,071,414 

122,071,614 

116,150,169 

537,478,212 

32.04 

23.64 

22.71 

21.61 

100.00 

49,217 

62,830 

60,802 

57,510 

230,359 

21.37 

27.27 

26.39 

24.97 

100.00 

57 

108 

43 

14 

222 

0.12 

0.17 

0.07 

0.02 

0.10 

19 

29 

53 

22 

123 

0.04 

0.05 

0.09 

0.04 

0.05 

8 

16 

26 

19 

69 

0.02 

0.03 

0.04 

0.03 

0.03 

a School year: July to June. All boneless beef with indicator organism critical limit exceeds was rejected for purchase by AMS and thus not 

distributed to the National School Lunch Program or other federal nutrition assistance programs. To convert pounds to kilograms, 

multiply by 0.45359237. 

b Standard plate count critical limit: 100,000 CFU g 1

. c Total coliforms critical limit: 1,000 CFU g 1

. d E. coli critical limit: 500 CFU g 1

. 
J. Food Prot., Vol. 78, No. 9 NATIONAL SCHOOL LUNCH PROGRAM BEEF TESTING 1659 

TABLE 3. Incidence of E. coli O157:H7 and Salmonella in ground beef produced for AMS during school years 2011 to 2014a

Tonnage Lot count E. coli O157:H7 positiveb Salmonella positivec

School year lb % No. % No. % No. % 

2011 

2012 

2013 

2014 

Total 

134,099,784 

106,085,081 

95,640,940 

92,305,179 

428,130,984 

31.32 

24.78 

22.34 

21.56 

100.00 

10,107 

15,734 

10,503 

10,183 

46,527 

21.72 

33.82 

22.57 

21.89 

100.00 

1 

11 

12 

6 

30 

0.01 

0.07 

0.11 

0.06 

0.06 

82 

149 

88 

41 

360 

0.81 

0.95 

0.84 

0.40 

0.77 

a School year: July to June. All E. coli O157:H7–positive ground beef and all Salmonella-positive ground beef was rejected for purchase by 

AMS and thus not distributed to the National School Lunch Program or other federal nutrition assistance programs. To convert pounds to 

kilograms, multiply by 0.45359237. 

b E. coli O157:H7 critical limit: positive (þ) result 325 g 1

. c Salmonella critical limit: positive (þ) result 25 g 1

. 

For boneless beef, of the 222 samples with concentrations of SPCs exceeding the AMS purchase specifcation 

critical limit, 1 sample (0.50%) was positive for E. coli

O157:H7, and 2 samples (0.90%) were positive for 

Salmonella. Of the 123 samples with concentrations of total 

coliforms exceeding the AMS purchase specifcation critical 

limit, no sample was positive for E. coli O157:H7, and 5 

samples (4.10%) were positive for Salmonella. Of the 69 

samples with concentrations of E. coli exceeding the AMS 

purchase specifcation critical limit, no sample was positive 

for E. coli O157:H7, and 3 samples (4.30%) were positive 

for Salmonella (Table 5). 

For ground beef, of the 20 samples with concentrations 

of SPCs exceeding the AMS purchase specifcation critical 

limit, no sample was positive for E. coli O157:H7, and 3 

samples (15.00%) were positive for Salmonella. Of the 17 

samples with concentrations of total coliforms exceeding the 

AMS purchase specifcation critical limit, no sample was 

positive for E. coli O157:H7, and 2 samples (11.80%) were 

positive for Salmonella. Of the 22 samples with concentrations of E. coli exceeding the AMS purchase specifcation 

critical limit, no sample was positive for E. coli O157:H7, 

and 1 sample (4.50%) was positive for Salmonella (Table 6). 

The r values computed as part of this study did not indicate 

demonstrable positive or negative correlations between 

indicator microorganisms and pathogens (Tables 5 and 6). 

Of the 233 boneless beef isolates of Salmonella that 

were serotyped, Dublin was the most commonly observed 

serotype (114 isolates; 48.93% of total) of the 23 serotypes 

identifed (Fig. 1). For the 40 Salmonella isolates recovered 

from ground beef, Dublin was also the most commonly 

observed serotype (15 isolates; 37.50% of total) of the 15 

serotypes identifed (Fig. 2). One of the isolates from ground 

beef could not be defnitively serotyped and was classifed as 

Salmonella Montevideo:Anatum. The following Salmonella

serotypes were recovered from boneless beef but not from 

ground beef: 3,10:e,h: , Amager, Brandenburg, Give, 

i4,[5],12:i: , Infantis, Muenster, Reading, Senftenberg, 

Sundsvall, Uganda, and Virchow. Conversely, the following 

Salmonella serotypes were recovered from ground beef but 

not from boneless beef: Bovismorbifcans, Enteritidis, and 

Gaminara. 

DISCUSSION

The AMS microbiological purchase specifcations for 

boneless and ground beef are based on dispositional testing 

for pathogens and on monitoring process control through 

indicator microorganisms. The observation that less than 1% 

TABLE 4. Incidence of indicator organism concentrations exceeding critical limits in ground beef produced for AMS during school years

2011 to 2014a

Tonnage Lot count 

SPC critical 

limit exceededb

Coliform critical 

limit exceededc

E. coli critical 

limit exceededd

School year lb % No. % No. % No. % No. % 

2011 

2012 

2013 

2014 

Total 

134,099,784 

106,085,081 

95,640,940 

92,305,179 

428,130,984 

31.32 

24.78 

22.34 

21.56 

100.00 

10,107 

15,734 

10,503 

10,183 

46,527 

21.72 

33.82 

22.57 

21.89 

100.00 

0 

10 

7 

3 

20 

0.00 

0.06 

0.07 

0.03 

0.04 

0 

11 

4 

2 

17 

0.00 

0.07 

0.04 

0.02 

0.04 

5 

10 

5 

2 

22 

0.05 

0.06 

0.05 

0.02 

0.05 

a School year: July to June. All ground beef with indicator organism critical limit exceeds was rejected for purchase by AMS and thus not 

distributed to the National School Lunch Program or other federal nutrition assistance programs. To convert pounds to kilograms, 

multiply by 0.45359237. 

b Standard plate count critical limit: 100,000 CFU g 1

. c Total coliforms critical limit: 1,000 CFU g 1

. d E. coli critical limit: 500 CFU g 1

. 
1660 DOERSCHER ET AL. J. Food Prot., Vol. 78, No. 9 

TABLE 5. Relationship between indicator organism concentrations exceeding critical limits and pathogen positives in boneless

beef produced for AMS during school years 2011 to 2014a

Result count Salmonella E. coli O157:H7 Result count Salmonella E. coli O157:H7 

Indicator of critical Indicator of critical 

organism limit exceeded Positive r Positive r organism limit exceeded Positive r Positive r

SPCb 222 2 0.002 1 0.007c SPCb 20 3 0.034c 0 0.001 

Coliformd 123 5 0.013e 0 0 Coliformd 17 2 0.024c 0 0 

E. coli f 69 3 0.011e 0 0 E. colie 22 1 0.009 f 0 0.001 

a Lot count: 230,359. 

b Standard plate count critical limit: 100,000 CFU g 1

. c P , 0.01. d Total coliforms critical limit: 1,000 CFU g 1

. e P , 0.0001. 

f E. coli critical limit: 500 CFU g 1

. 

of the boneless and ground beef lots described in this study 

were positive for E. coli O157:H7 or for Salmonella

suggests the beef intended for distribution to the NSLP is 

unlikely to contain pathogens. Moreover, all of the 

pathogen-positive lots of beef described in this study were 

rejected for purchase by AMS and thus not distributed to the 

NSLP. Lots rejected for purchase were sent to commercial 

cooking operations and sold commercially. AMS purchase 

specifcations require AMS vendors to use a minimum of 

two pathogen intervention steps. Such steps, including 

carcass washes (6, 17, 22, 29–31) and rapid chilling of beef 

(5), are effective for reducing pathogens on beef and likely 

contributed to the low pathogen positive rate observed here. 

In addition to a minimum of two pathogen interventions, AMS purchase specifcations also require removal of 

major lymph glands, including the prescapular, popliteal, 

TABLE 6. Relationship between indicator organism concentrations exceeding critical limits and pathogen positives in ground

beef produced for AMS during school years 2011 to 2014a

a Lot count: 46,527. 

b Standard plate count critical limit: 100,000 CFU g 1

. c P , 0.0001. d Total coliforms critical limit: 1,000 CFU g 1

. e E. coli critical limit: 500 CFU g 1

. f P , 0.05. 

and prefemoral lymph nodes (3). This requirement began 

approximately 40 years ago. Given that cattle lymph nodes 

have been shown to harbor Salmonella (7, 10, 14–16, 25), it 

is reasonable to hypothesize that removal of the major 

lymph glands contributed to the low level of Salmonella

observed in beef produced for AMS. However, data from 

this study cannot, by themselves, be used to test the 

hypothesis. Continued refnement of AMS purchase specifcations will thus beneft from additional research to further 

discern the overall importance of lymph nodes to Salmonella

contamination in ground beef, including a cost-beneft 

analysis of lymph node removal, vaccination for reducing 

Salmonella in lymph nodes, or both (11), in ground beef 

production. 

The serotypes observed among the Salmonella isolates 

described in this study are similar to those previously 

FIGURE 1. Salmonella serotypes recovered from boneless beef produced for AMS during school years 2011 to 2014. All Salmonellapositive beef was rejected for purchase by AMS and thus not distributed to the National School Lunch Program or other federal nutrition

assistance programs. 
J. Food Prot., Vol. 78, No. 9 NATIONAL SCHOOL LUNCH PROGRAM BEEF TESTING 1661 

FIGURE 2. Salmonella serotypes recovered from ground beef produced for AMS during school years 2011 to 2014. All Salmonellapositive beef was rejected for purchase by AMS and thus not distributed to the National School Lunch Program or other federal nutrition

assistance programs. 

reported for Salmonella recovered from beef at processing 

establishments and at retail (9) in the United States. They are 

also similar to those recovered from cattle in U.S. feedlots 

(8) and from cattle upon arrival at processing establishments 

(13–15). The one notable exception, however, is that no 

Salmonella Kentucky serotypes were observed among the 

AMS isolates described in this study. 

Aside from pathogen testing, measuring concentrations 

of indicator microorganisms is a useful tool for examining 

an establishment’s overall process control capability (23,

24). Less than 1% of all lots of boneless and ground beef 

were found to exceed critical limits for E. coli, total 

coliforms, or SPCs. AMS monitors indicator organisms not 

as a predictor of or surrogate for pathogen-positive samples 

but rather to assess an establishment’s ability to produce 

beef in a sanitary manner. An establishment that loses 

process control must conduct a cause-and-effect analysis and 

implement corrective actions before resuming production for 

AMS (3). Taken together, the results for pathogen testing 

and indicator microorganism testing described in this study 

offer reassurance that monitoring process control is a useful 

purchase specifcation. 

Findings from a recent study by Ollinger et al. (21), in 

which AMS purchase specifcation data were compared with 

those from FSIS baseline and regulatory sampling programs, 

suggest that establishments actively supplying beef to the 

NSLP are less likely to have samples test positive for 

Salmonella compared with establishments that do not supply 

beef to the NSLP. The reasons for the observed differences 

in Salmonella incidence among the sampling sets, however, 

are not clear. Indeed, caution should be exercised in 

comparing AMS results with those of FSIS. Notwithstanding the requirement that AMS samples be processed 

according to FSIS MLG protocols (27), there are stark 

differences between the AMS purchase specifcation testing 

protocol and the FSIS baseline and regulatory testing 

protocol, including sample collection personnel, collection 

frequency, and purpose of sampling. In addition, all beef 

procured by AMS must be produced and processed under 

FSIS inspection (3). As such, AMS purchase specifcations 

are used in addition to, not in lieu of, FSIS testing and 

related inspection requirements. 

The NRC reviewed the AMS ground beef purchase 

program and published its fndings in 2010 (20). Building 

upon the NRC review, the NACMCF reviewed the program 

and published its fndings in 2013 (19). AMS has 

implemented most of the recommendations of the NRC 

and the NACMCF, including discontinuing testing for E.

coli O157:H7 and Salmonella in raw beef destined for 

cooking by using a validated time and temperature protocol 

at an FSIS-inspected establishment. In addition, AMS, in 

2014, began testing 1 of every 10 lots, drawn at random, of 

beef destined for delivery to recipient agencies raw for the 

presence of the six additional serotypes of Shiga toxin– 

producing E. coli–declared adulterants by FSIS in 2012 (i.e., 

O26, O45, O103, O111, O126, and O145). 

AMS purchase specifcations are a balance of scientifc 

principles, food (security) needs, and stakeholder input. 

Funds used for AMS purchase specifcation microbiological 

testing come from those appropriated by Congress to the 
1662 DOERSCHER ET AL. 

USDA to administer various nutritious assistance programs. 

Thus, every dollar spent on microbiological testing is a 

dollar that could otherwise be used to purchase additional 

food for recipients in need. As a government agency, AMS 

is responsible for considering the views of all stakeholders, 

including program recipients. Most of these views represent 

value judgments and are thus not quantifable. The intent of 

sharing the AMS microbiological testing data described in 

this article is to help facilitate a transparent and ongoing 

discussion among AMS and its stakeholders about the 

continual refnement of NSLP beef purchase specifcations 

to ensure the ongoing procurement of safe, wholesome, and 

nutritious food. 

ACKNOWLEDGMENTS

We thank the staff at each AMS beef vendor for collecting samples 

and those at each ADL for analyzing samples and transferring the resultant 

data to AMS. We thank our colleagues at the FSIS Eastern Laboratory for 

serotyping Salmonella isolates. We also thank Mohammed Atif Jalal, AMS, 

for developing the database in which all of the data described in this article 

are housed and analyzed and Michael B. Feil, AMS, for assistance with 

statistical analyses of the data. 

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