AOAC 2018 Methods

B ird et al . : J ournal of AOAC I nternational V ol . 102, N o . 1, 2019  117

We would like to extend a special thanks to the following team members at Q Laboratories, Inc. for their efforts during the collaborative study: Leo Horine, Nicole Klass, Brandi Heiland, T. Shane Wilson, Hannah Meibers, Kiel Fisher, Dane Brooks, and Colleen Sweeney.

DNA in the matrix (14). These rates are reasonably expected as reported by Edson et. al (15) using compiled data from 9 years of multilaboratory proficiency testing, which reports a 5.9–13.6% FN rate and a FP fraction below 5%. The use of an APC method rather than one optimized for growth of lactic acid bacteria likely contributed to the observed low aerobic plate counts (2.5 × 10 1 CFU/g). The matrix was later evaluated for lactic acid bacterial counts internally and by six collaborators, averaging 1.6 × 10 8 CFU/g. The lactic acid results support that the use of APC for the evaluation of background flora was not the ideal method. Overall, the data generated during this evaluation demonstrates the reproducibility of this method as proven by both the low amount of discrepant results and robust s r , s R . and s L values (including confidence intervals). No statistically significant differences were observed between the presumptive candidate method and the confirmed results.

References

(1) Chen, Y. (2012) in Bad Bug Book – Foodborne Pathogenic Microorganisms and Natural Toxins , 2nd Ed., K.A. Lampel, S. Al-Khaldi, & S.M. Cahill (Eds), U.S. Food and Drug Administration, Silver Spring, MD, 51–53 (2) Enterobacter sakazakii ( Cronobacter spp.) in Powdered Follow-Up Formulae (2008) Microbiological Risk Assessment Series 15, World Health Organization, Geneva, Switzerland, http://www.who.int/foodsafety/publications/micro/MRA_ followup.pdf (accessed December 2017) (3) Centers for Disease Control and Prevention, Cronobacter : Prevention & Control, https://www.cdc.gov/cronobacter/ prevention.html (accessed December 2017) (4) Official Methods of Analysis (2016) 20th Ed., AOAC INTERNATIONAL, Rockville, MD, Appendix J (5) ISO 22964:2017: Microbiology of the Food Chain – Horizontal Method for the Detection of Cronobacter spp. , International Organization for Standardization, Brussels, Belgium (6) ISO 4833-1:2013: Microbiology of the Food Chain – Horizontal Method for the Enumeration of Microorganism – Part 1: Colony Count at 30°C by the Pour Plate Technique , International Organization for Standardization, Brussels, Belgium (7) Least Cost Formulations, Ltd, MPN Calculator, Version 1.6, http://www.lcfltd.com/customer/LCFMPNCalculator.exe (accessed December 2017) (8) ISO 6579-1:2017: Microbiology of the Food Chain – Horizontal Method for the Detection, Enumeration and Serotyping of Salmonella — Part 1: Detection of Salmonella spp. , International Organization for Standardization, Brussels, Belgium (9) Official Methods of Analysis (2011) 18th Ed., AOAC INTERNATIONAL, Gaithersburg, MD, Method 2011.17 (10) Wehling, P., LaBudde, R., Brunelle, S., & Nelson, M. (2011) J. AOAC Int. 94 , 335–347 (11) Least Cost Formulations, Ltd, AOAC Binary Data Interlaboratory Study Workbook (2013), http://lcfltd.com/aoac/ aoac-binary-v2-3.xls (accessed December, 2017) (12) ISO 18593:2004: Microbiology of Food and Animal Feeding Stuffs – Horizontal Methods for Sampling Techniques from Surfaces Using Contact Plates and Swabs , International Organization for Standardization, Brussels, Belgium (13) Njongmeta, N.A., Hall, P.A., Ledenbach, L., & Flowers, R.S. (2013) in Compendium Methods for Microbiological Examination of Foods , 5th Ed., Y. Salfinger, & M.L. Tortorello (Eds), American Public Health Association, Washington, DC, 229–237 (14) Ceuppens, S., Li, D., Uyttendaele, M., Renault, P., Ross, P., Van Ranst, M., Cocolin, L., & Donaghy, J. (2014) Compr. Rev. Food Sci. Food Saf. 13 , 551–577. doi:10.1111/1541-4337.12072 (15) Edson, D.C., Empson, S., & Massey, L.D. (2009) J. Food Saf. 29 , 525–530. doi:10.1111/j.1745-4565.2009.00174.x

Recommendations

It is recommended that the 3MMDA2 – Cronobacter method be adopted as Official First Action status for the detection of Cronobacter species in powdered infant formula with probiotics (10 and 300 g), powdered infant cereal without probiotics (10 and 300 g), lactose powder (10 g), and environmental surface sponges (stainless steel).

Acknowledgments

We would like to extend a sincere thank you to the following collaborators for their dedicated participation in this study: Maya Achen, Sara Mager, Carey Walker, and Yingying Hong, Abbott Laboratories (Columbus, OH) Adriana Cruz, DSMNutritional Products (Guadalajara, Mexico) Gina Masanz, Andy Scollon, and Pam McKelvey, Land O’Lakes, Inc. (Arden Hills, MN) Irma Podoreski, Anita Mustafic, Tihana Abramovic, and Miruska Matijevic, HiPP Croatia d.o.o (Glina, Croatia) Angela Winslow, Joint Institute for Food Safety and Applied Nutrition (College Park, MD) Carmen Tinajero and Cristina Luquin, Cencon Centro de Control (Guadalajara, Mexico) Bryan Schindler, Jesse Miller, Eric Budge, Susan Wheeler, and Kyle Martin, NSF International (Ann Arbor, MI) Leslie Thompson, Cole Liska, Nathan Clemens, Vanguard Sciences (North Sioux City, SD) Satoshi Ishii and Isabel Ricke, University of Minnesota, Department of Soil, Water, and Climate BioTechnology Institute (St. Paul, MN) Wenqing Xu, University of Louisiana, School of Nutrition and Food Sciences (Baton Rouge, LA) Li Maria Ma, Claudia Diaz, Santiago Molina, Juan Cuellar, and Carlos Somoza, Oklahoma State University (Stillwater, OK)