Food Protection Trends - September/October 2024 - 342

the use of the process seemed to be determined by the
annual shelling output, because only 25.0% of shellers who
shell <1 million lb of pecans use one of these processes.
Previous research has determined that hot water treatments
at 176 and 194°F (80 and 90°C) for 3-5 min were effective
at achieving a 5-log CFU/g reduction of Salmonella enterica
and Escherichia coli O157:H7, whereas a treatment at 158°F
(70°C) for 5 min was effective at achieving a 5-log CFU/g
reduction of Listeria monocytogenes on in-shell pecans
(15). Steam was also found to be an effective treatment at
reducing the Salmonella surrogate Enterococcus faecium by
5-log CFU/g at 194°F (90°C) for 15 s, while also delaying
the rancidity of the kernel and potentially extending shelf
life (14). This is an effective way to reduce pathogen levels
while still maintaining quality. For many operations,
implementation of these processes may be cost prohibitive,
but there are designs and plans available for small-scale
shellers to adapt a single-pass chlorinated water treatment
for inshell pecans at a low cost within their operation (19).
Although a majority of the shellers use some form of hot
water or steam, the results were not as high as previously
reported by the survey conducted by the NPSA in 2013
that was used to develop a risk assessment of salmonellosis
for pecan consumption in the United States (12), finding
that 77% (17/22) use a hot water or steam process to treat
in-shell pecans, compared with 56.5% in this survey. These
numbers may vary because the NPSA only distributed the
survey to their members, who are often the larger shellers
that are more likely to have a hot water or steam process in
place, whereas this survey was distributed through various
outlets that might reach smaller shelling operations.
Outside of treating in-shell pecans with a hot water or
steam process, most shellers do not use any treatment on the
pecan kernel after shelling to reduce potential contamination.
Although this may be the case, pecan kernels generally
undergo a drying process that often includes the use of hot
air at approximately 140°F (60°C), which could result in a
slight pathogen reduction (6). This is generally not seen as a
control step because the time may vary and is dependent on
obtaining the desired final kernel moisture of 4% (20). Of the
operations that use a process to treat kernels, PPO and PAA
were the primary treatments used. PPO has been found to be
an effective treatment at reducing Salmonella and E. coli on
pecan and other tree nuts (5, 22). Although PPO treatment
may be effective at reducing pathogenic load, it is not often
REFERENCES
1. Bakin, B. C., C. J. McGovern, M. Melendez,
C. Kessler, F. Critzer, C. M. Rock, R. L.
Buchanan, D. W. Schaffner, M. D. Danyluk,
B. B. Kowalcyk, K. M. Morgan, L. K. Strawn,
and A. M. Hamilton. 2023. Ranking food
safety priorities of the fresh produce industry
in the United States. J. Food Prot. 86:100167.
2. Bardsley, C. A., K. Chasteen, D. Shapiro-Ilan,
C. H. Bock, B. A. Niemira, and G. D. Kumar.
2023. Transfer of generic Escherichia coli and
attenuated Salmonella enterica Typhimurium
from the soil to the surface of in-shell pecans
during harvest. Heliyon 9:9.
3. Bertoldi, B., C. A. Bardsley, C. A. Baker, C.
R. Pabst, A. Gutierrez, J. De, Y. Luo, and K.
R. Schneider. 2021. Determining bacterial
load and water quality of tomato flume
tanks in Florida packinghouses. J. Food Prot.
84:1784-1792.
a logistical or financially viable option for smaller pecan
shellers, because this would require significant resources to
implement this system in their operation or cost to send to a
third-party facility to perform the treatment. Although not
as effective as PPO, PAA as a treatment of pecan kernels was
found to reduce up to 2.4 log CFU/g of Salmonella at 40
µg/mL. Oil roasting is a process in which pecans are moved
through heated oil, which alters the flavor and texture of the
kernel, and has been found to reduce up to 3.5 log CFU/g of
Salmonella on pecan kernels when treated for 30 s at 260°F
(127°C) (6). Surprisingly, oil roasting was not identified
as a treatment step used by shellers. This may be due to oil
roasting not occurring at the shelling facility or only being
performed if requested by buyers. Available and effective
alternative treatments to eliminate pathogens on the surface
of pecans should be evaluated for use by pecan shellers.
CONCLUSIONS
Pecans are frequently consumed either as an ingredient
or raw by consumers in the United States. Therefore, best
practices to ensure food safety are critical for the continued
safety of consumers of raw, shelled pecans. The results of the
survey provided insight into food safety and quality trends
that are based on the size of an operation and its capacity
to implement certain control measures. To provide shellers
with an understanding of best practices, the development of
food safety guidance documents and employee trainings may
be needed. Likewise, the use and monitoring of sanitizers
to prevent cross-contamination during conditioning should
be encouraged, particularly if hot water or steam sanitation
processes are not used to further reduce microbial hazards.
ACKNOWLEDGMENTS
We thank the food safety and agricultural economic
specialists for reviewing the survey and providing feedback,
and the National Pecan Shellers Association, the Georgia
Pecan Growers Association, Oklahoma Pecan Growers
Association, North Carolina Pecan Growers Association,
Mississippi Pecan Growers Association, Western Pecan
Growers Association, Texas Pecan Growers Association, and
the Louisiana Pecan Growers Association for assisting in
the distribution of the survey. CAB is supported by the U.S.
Department of Agriculture, Agriculture Research Service
National Programs through Current Research Information
System project 6042-21220-014-000.
342 Food Protection Trends September/October
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