Food Protection Trends - May/June 2022 - 263

rate method performance with that matrix. The amount
of testing needed can depend on the similarity of the
new matrix to a validated matrix, as well as other factors
affecting the riskiness of the matrix, and an approach to
this decision was presented by Brown et al. (7). For this
purpose, a single strain generally is selected, commonly
one associated with the matrix, and preferably is isolated
from the matrix production environment, ingredients, or
final product. Use of strains that have created previous
contamination issues in a plant environment or persistent
contaminators that have eluded sanitization techniques can
give increased confidence in the method. However, this
approach is not always possible, it ties the matrix validation
to a specific manufacturer's product, and it does not allow
generic use of the matrix validation study.
CONCLUSION
Small and large inhouse laboratories and commercial
laboratories often do not have the resources to gather,
identify, and isolate strains or serotypes from naturally
contaminated samples or the ability to maintain large
collections. Although pathogen and serotype or serovar
selection is an important consideration to method and
matrix application studies, it appears that the best course
of action is to rely on the inclusivity data produced during
a method's validation and accreditation as the primary
REFERENCES
1. Aguilar, C., I. Bertani, and V. Venturi. 2003.
Quorum-sensing system and stationary-phase
sigma factor (rpoS) of the onion pathogen
Burkholderia cepacia genomovar I type strain,
ATCC 25416. Appl. Environ. Microbiol.
69:1739-1747.
2. American Type Culture Collection. 2021.
Microbiology collections. Available at:
https://www.atcc.org/en/Products/
Collections/Microbiology_Collections.aspx.
Accessed 20 December 2021.
3. Association of Official Analytical Collaboration
International (AOAC). 2012.
Appendix J. AOAC International methods
committee guidelines for validation of
microbiological methods for food and
environmental surfaces. Official methods
of analysis of AOAC International. 21st
Edition. AOAC International, Rockville, MD.
Available at: http://www.eoma.aoac.org/
app_j.pdf. Accessed 7 January 2022.
4. Bean, D. C., and L. S. Post. 2014. Chocolate
and confectionary, p. 269-293. In J. B.
Gurtler, M. P. Doyle, and J. L. Kornacki
(ed.) The microbiological safety of low
water activity foods and spices. First Edition.
Springer, New York.
5. Bird, P. M., M. S. Brown, J. E. Dell'Aringa,
L. A. Hahn, J. D. Legan, R. D. Maus, S. Pollard,
and L. S. Post. 2019. Microbiological
detection methods-assuring the right fit.
Food Prot. Trends 39:417-419.
6. Boundy-Mills, K., M. Hess, A. R. Bennett,
M. Ryan, S. Kang, D. Nobles, J. A. Eisen,
P. Inderbitzin, I. R. Sitepu, T. Torok, D. R.
Brown, J. Cho, J. E. Wertz, S. Mukherjee,
S. L. Cady, and K. McCluskey. 2015. The
United States Culture Collection Network
(USCCN): enhancing microbial genomics
research through living microbe culture
collections. Appl. Environ. Microbiol.
81:5671-5674.
7. Brown, M. S., P. M. Bird, S. Brunelle,
W. E. Chaney, C. A. Kennett, J. D. Legan,
R. D. Maus, L. Post, and S. Pollard. 2021.
Alternative approaches for qualitative
microbiological method matrix additions.
Food Prot. Trends 41:152-162.
8. Buehler, A. J., M. Wiedmann, Z. Kassaify,
and R. A. Cheng. 2019. Evaluation of invA
diversity among Salmonella species suggests
why some commercially available rapid
detection kits may fail to detect multiple
Salmonella subspecies and species. J. Food
Prot. 82:710-717.
9. Calhoun, S., L. Post, B. Warren, S. Thompson,
and A. R. Bontempo. 2018. Prevalence and
concentration of Salmonella on raw, shelled
peanuts in the United States. J. Food Prot.
81:1755-1760.
10. Carlin, C. R., S. S. Lau, R. A. Cheng, A. J.
Buehler, Z. Kassaify, and M. Wiedmann.
2020. Validation using diverse, difficult-todetect
Salmonella strains and a dark chocolate
matrix highlights the critical role of strain
selection for evaluation of simplified, rapid
PCR-based methods offering next-day time
to results. J. Food Prot. 83:1374-1386.
11. Carrasco, E., A. Morales-Rueda, and R. M.
García-Gimeno. 2012. Cross-contamination
and recontamination by Salmonella in foods:
a review. Food Res. Int. 45:545-556.
12. Ceylan, E., and D. A. Bautista. 2015.
Evaluating Pediococcus acidilactici and
Enterococcus faecium NRRL B-2354 as
thermal surrogate microorganisms for
Salmonella for in-plant validation studies of
low-moisture pet food products. J. Food Prot.
78:934-939.
13. Channaiah, L. H., E. S. Holmgren,
M. Michael, N. J. Sevart, D. Milke, C. L.
Schwan, M. Krug, A. Wilder, R. K. Phebus,
H. Thippareddi, and G. Milliken. 2015.
Validation of baking to control Salmonella
serovars in hamburger bun manufacturing,
and evaluation of Enterococcus faecium
ATCC 8459 and Saccharomyces cerevisiae as
nonpathogenic surrogate indicators. J. Food
Prot. 79:544-552.
source documenting the method's ability to recover strain
variability of the target pathogen. Detailed selection based
on strain-level phenotypic or genetic determinants appears
unjustified for evaluation with new matrices and could lead
to inaction, but where stakeholders know of strong links
among a particular process environment, matrix, and strain
of pathogen, this would be a reason to favor that strain.
More generally, the commercial availability of standardized
strains can help laboratories facilitate method application
work in a harmonized manner within the industry and
could benefit from the expansion of collection diversity.
It is arguably better to conduct matrix verification and
validation activities with one or more appropriately stressed
pathogen- or serovar-level representatives readily available
to any laboratory than to take no action as a result of
inaccessibility or complexity in selecting specific strains. The
stresses applied to these cultures could be tailored for food
matrix validations and verifications based on the probable
injury sustained in processing. For instance, standardized,
mass-produced, lyophilized strains are readily available and
can provide a level playing field for slow-growing strains in
complex processed food products.
ACKNOWLEDGMENTS
The authors are grateful to Thomas Hammack of the FDA for
informative discussions and guidance on method validation.
May/June Food Protection Trends 263
https://www.atcc.org/en/Products/Collections/Microbiology_Collections.aspx https://www.atcc.org/en/Products/Collections/Microbiology_Collections.aspx http://www.eoma.aoac.org/app_j.pdf http://www.eoma.aoac.org/app_j.pdf
Food Protection Trends - May/June 2022

Table of Contents for the Digital Edition of Food Protection Trends - May/June 2022
