UPDATE ON PECAN
INDUSTRY PREVALENCE
STUDY
Michelle Danyluk
mddanyluk@ufl.edu
Tuesday March 25th, 2014
PECAN SURVEY

Objective. To determine the prevalence and
levels of Salmonella on naturally-contaminated
in-shell pecans throughout the pecan producing
regions of North America over a four year period.

Two “high” years


Two “ low” years


1,500 Samples per year
1,000 Samples per year
Four “varieties”
Mexican Improved
 Western Improved
 Southeastern Improved
 Native/Seedling

PECAN SURVEY
 Deliverables:
Frequency of Salmonella on surveyed
pecans
2. Serotypes of Salmonella identified in
pecan survey samples.
3. MPN (amount) of Salmonella in
positive pecan survey samples.
1.
2013 PARTICIPANTS

8 Sheller locations located across the US


Included small, medium, and large facilities
Each facility was asked to collect samples based
on the size of their operation and the proportion
of varieties they run

Sample sizes ranged from 12 to 313
2013 SAMPLING

Each Sheller received a letter from UF stating:
2013/2014 Pecan Safety Survey. Included in this
Thank you for agreeing to participate in the 2010/2011
mailing you will find:
1) Instructions for sampling your pecans
2) Sampling kits to collect your samples (in 16x16 zip top bags)
Each kit contains:
a. One pair sterile, disposable gloves
b. One large sterile, disposable scoop
c. One 12x12 zip top bag with label
3) Five return address labels to FedEx the samples you collect back to me.
Your facility will be responsible for collecting ___________ samples, made up of:
_____ Mexican Improved
_____ Western Improved
_____ Southern Improved
_____ Native/Seedling
2013 SAMPLING

And giving the following instructions:
1) Get a sample kit (a 16x16 zip top bag)
2) Remove the labeled 12x12 zip top bag
3) Fill in the date, and check the variety (one of Mexican improved, Western Improved, Southern
Improved or Native Seedling) on the label
Put Date Here
Date:____________________
___ Mexican Improved
Check one variety line. i.e. if I am collecting
___ Western Improved
Southern Improved I check the line next to
___ Southern Improved
Southern Improved
___ Native/Seedling
PS-2013PS-2010-_____
For Lab Use only
4)
5)
6)
7)
Wash your hands with soap and water, dry with a paper towel
Put on the sterile disposable gloves
Remove the sterile scoop from its packaging by tearing at the “TEAR HERE”
Use scoop to put approximately 1 lb of inshell pecans into labeled 12x12 zip top bag (i.e. always
at a the same point during inshell receipt and grading*)
8) Seal the labeled 12x12 zip top bag
9) Remove gloves, and dispose of gloves and scoop in garbage
10) Store samples at room temperature prior to returning to UF. Samples should not be held longer
than 1 month.
*As each sheller handles its inshell differently, please select a standard location in your facility to collect
inshell pecan samples and always sample from the same point.
2013 SAMPLING

Upon receipt at UF:
Samples are randomly assigned a PS number
 Information on Sampling Date and Variety is
collected
 A 100-g subsample, labeled only with the PS number
is weighed out and shipped to Eurofins for initial
Salmonella testing
 Remaining sample is stored at 40F


No record of sampling location is kept
PECAN SURVEY - FREQUENCY
500 g In Shell Pecans
100 g In Shell Pecans
DFA, AOAC method
+/- Salmonella
PECAN SURVEY - FREQUENCY
500 g In Shell Pecans
If Positive
100 g In Shell Pecans
400 g In Shell Pecans
DFA, AOAC method
UF, FDA method
+/- Salmonella
MPN “amount” of
Salmonella
If Positive
Salmonella Serotype
“Type” of Salmonella
If Positive
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Mexican
Improved
4/187
1/290
2/372
Western
Improved
4/302
3/443
2/360
Southern
Improved
4/336
1/502
2/199
Native
Seedling
1/149
2/251
1/112
Southern
/Native
-
0/3
TOTAL
13/974
7/1,489
7/943
27/3,396
Samples
Requested
Samples
Received
03/20/14
Samples
Processed
03/20/14
Salmonella
positive
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Samples
Requested
Mexican
Improved
4/187
1/290
2/372
231
Western
Improved
4/302
3/443
2/360
396
Southern
Improved
4/336
1/502
2/199
440
Native
Seedling
1/149
2/251
1/112
210
Southern
/Native
-
0/3
TOTAL
13/974
7/1,489
7/943
27/3,396
1,250
Samples
Received
03/20/14
Samples
Processed
03/20/14
Salmonella
positive
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Samples
Requested
Samples
Received
03/20/14
Mexican
Improved
4/187
1/290
2/372
231
191
Western
Improved
4/302
3/443
2/360
396
275
Southern
Improved
4/336
1/502
2/199
440
382
Native
Seedling
1/149
2/251
1/112
210
57
Southern
/Native
-
0/3
-
-
TOTAL
13/974
7/1,489
1,250
905
7/943
27/3,396
Samples
Processed
03/20/14
Salmonella
positive
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Samples
Requested
Samples
Received
03/20/14
Samples
Processed
03/20/14
Mexican
Improved
4/187
1/290
2/372
231
191
178
Western
Improved
4/302
3/443
2/360
396
275
275
Southern
Improved
4/336
1/502
2/199
440
382
309
Native
Seedling
1/149
2/251
1/112
210
57
57
Southern
/Native
-
0/3
-
-
-
TOTAL
13/974
7/1,489
1,250
905
819
7/943
27/3,396
Salmonella
positive
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Samples
Requested
Samples
Received
03/20/14
Samples
Processed
03/20/14
Salmonella
positive
Mexican
Improved
4/187
1/290
2/372
231
191
178
4
Western
Improved
4/302
3/443
2/360
396
275
275
2
Southern
Improved
4/336
1/502
2/199
440
382
309
3
Native
Seedling
1/149
2/251
1/112
210
57
57
2
Southern
/Native
-
0/3
-
-
-
-
TOTAL
13/974
7/1,489
1,250
905
819
11
7/943
27/3,396
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Samples
Requested
Samples
Received
03/20/14
Samples
Processed
03/20/14
Salmonella
positive
Mexican
Improved
4/187
1/290
2/372
231
191
178
4
Western
Improved
4/302
3/443
2/360
396
275
275
2
Southern
Improved
4/336
1/502
2/199
440
382
309
3
Native
Seedling
1/149
2/251
1/112
210
57
57
2
Southern
/Native
-
0/3
-
-
-
-
TOTAL
13/974
7/1,489
1,250
905
819
11
7/943
27/3,396
2013 to date prevalence = 11/819 = 1.3%
2013 RESULTS
Variety
2010
Results
2011
Results
2012
Results
Samples
Requested
Samples
Received
03/20/14
Samples
Processed
03/20/14
Salmonella
positive
Mexican
Improved
4/187
1/290
2/372
231
191
178
4
Western
Improved
4/302
3/433
2/360
396
275
275
2
Southern
Improved
4/336
1/502
2/199
440
382
309
3
Native
Seedling
1/149
2/251
1/112
210
57
57
2
Southern
/Native
-
0/3
-
-
-
-
TOTAL
13/974
7/1,479
1,250
905
819
11
7/943
27/3,396
2010 - 2013 to date prevalence = 38/4,215 = 0.9%
38/4,215
HOW DOES IT COMPARE?

Combined prevalence of 0.9%
(up from previous – 0.8%)
HOW DOES IT COMPARE?


Combined prevalence of 0.9%
Almonds

Survey of Almonds Kernels 100 g – Almonds Sampled at Handler
Year
Number Positive
of Total Tested
% Positive
2001
12 of 2,003
0.60
2002
24 of 2,012
1.2
2003
15 of 1,764
0.80
2004
12 of 1,643
0.73
2005
18 of 1,852
0.97
2006
31 of 1,899
1.6
2007
15 of 1,799
0.83
2010
10 of 1,000
1.00
Total
137 of 13,972
0.98
Danyluk et al., 2007 JFP; Basnal et al. 2010 JFP; Lambertini et al. 2012 FRI
HOW DOES IT COMPARE?


Combined prevalence of 0.9%
Almonds


Survey of Almonds Kernels 100 g – Almonds Sampled at Handler –
1.0% of 13,972 samples
Survey of In Shell Almonds 100 g – Almonds Sampled at Handler
Year
2006
2007
Total
Number Positive
of Total Tested
2 of 229
5 of 262
7 of 491
% Positive
0.87
2.2
1.4
Basnal et al. 2010 JFP
HOW DOES IT COMPARE?


Combined prevalence of 0.9%
Almonds



Survey of Almonds Kernels 100 g – Almonds Sampled at Handler –
1.0% of 13,972 samples
Survey of In Shell Almonds 100 g – Almonds Sampled at Handler –
1.4% of 491 samples
Pistachios (In Shell)

Survey of Pistachios 4/09 – 8/09 Sample at Silo 50g?
Type
# Positives of
Total Tested
Prevalence
(%)
In shell
Kernel
133 of 32,494
82 of 3,891
0.41
2.11
IEH Laboratories, 2009
HOW DOES IT COMPARE?


Combined prevalence of 0.9%
Almonds



Survey of Almonds Kernels 100 g – Almonds Sampled at Handler –
1.0% of 13,972 samples
Survey of In Shell Almonds 100 g – Almonds Sampled at Handler –
1.4% of 491 samples
Pistachios (In Shell)


Survey of Pistachios 4/09 – 8/09 Sample at Silo 50g - 0.4% of 32,949
Survey of Pistachios 2010, 2011, 2012 (ongoing sampling) 100 g
Year
# Positives of
Total Tested
Prevalence
(%)
2010
2011
Total
11/1,152
6/1,380
17/2,532
0.95
0.43
0.7
LJ Harris, UCD, Personal Communication
HOW DOES IT COMPARE?


Combined prevalence of 0.9%
Almonds



Pistachios (In Shell)



Survey of Almonds Kernels 100 g – Almonds Sampled at Handler –
1.0% of 13,972 samples
Survey of In Shell Almonds 100 g – Almonds Sampled at Handler –
1.4% of 491 samples
Survey of Pistachios 4/09 – 8/09 Sample at Silo 50g - 0.4% of 32,949
Survey of Pistachios 2010, 2011, 2012 (ongoing sampling) 100 g –
0.7% of 2,532 samples
Walnuts (In Shell)

Survey of Walnuts 2010, 2011, 2012 - 375 g
 2,000 samples, ca. 0.01-0.02% positive
LJ Harris, UCD, Personal Communication
HOW DOES IT COMPARE?


Combined prevalence of 0.9%
Almonds



Pistachios (In Shell)



Survey of Almonds Kernels 100 g – Almonds Sampled at Handler –
1.0% of 13,972 samples
Survey of In Shell Almonds 100 g – Almonds Sampled at Handler –
1.4% of 491 samples
Survey of Pistachios 4/09 – 8/09 Sample at Silo 50g - 0.4% of 32,949
Survey of Pistachios 2010, 2011, 2012 (ongoing sampling) 100 g –
0.7% of 2,532 samples
Walnuts (In Shell)
Survey of Walnuts 2010, 2011, 2012 - 375 g – 0.01-0.02% of ca. 2,000
samples
 Also tested for E. coli O157:H7 – None found


Peanuts (shelled)
 Survey
of peanut kernels 2008-2009 100g samples at -0.74% of 544
samples collected
APC, 2009
PECAN SURVEY
 Deliverables:
Frequency of Salmonella on surveyed
pecans
1.
1.
0.9% of 100g samples positive
Serotypes of Salmonella identified in
pecan survey samples.
3. MPN (amount) of Salmonella in
positive pecan survey samples.
2.
NEXT STEPS

2013 Sampling
Finish collecting and processing samples
 MPN analysis to determine the number of
Salmonella present in 2013 samples
 Determine Salmonella serotypes isolated in 2013


Finalize 4 year report
ACKNOWLEDGEMENTS
 National
Pecan Shellers Association
 Participating Pecan Shellers
 USDA CSREES NIFSI 2009-01951
 Eurofins



Michelle Lovett
Dean Willis
Genna Chadderdon
 Danyluk





testing laboratory in Jacksonville, FL
Lab
Pardeepinder Brar
Lisseth Proano
Loretta Friedrich
Gwen Lundy
Luis Martinez
QUESTIONS?