4. AOACRIMicroMethods-2018Awards

53

468 B ird et al .: J ournal of AOAC I nternational V ol . 100, N o . 2, 2017

Figure 2. (A) LPOD and (B) dLPOD values of candidate method versus reference method for raw chicken breast fillet (25 g).

chicken breast fillet, a statistically significant differencewas observed between the reference and candidate methods. The dLPOD C , being significantly greater than 0, showed an observed higher proportion of positive results by the candidate method compared to the reference method. One possible contribution for the higher observed proportion of positive results observed with the 3MMDA 2 – Listeria monocytogenes method was the use of DF Broth for the candidate method. This enrichment media formulation is less selective than the modified University of Vermont medium used in theUSDA/FSISMLGreferencemethod andmayhave contributed to the higher observed proportion positive results during the evaluation. Asecond possible contribution for the higher observed proportion of positive results is the length of the primary enrichment. Test portions evaluated by the 3MMDA2 – Listeria monocytogenes method were

incubated for a minimumof 28 h in the primary enrichment, whereas the USDA/FSIS MLG reference method had a maximum primary enrichment time of 26 h. No statistically significant difference was observed between the candidate method’s presumptive and confirmed results for this matrix.

Recommendations

It is recommended that the 3M MDA 2 – Listeria monocytogenes method be adopted as Official First Action status for the detection of L. monocytogenes in a variety of foods and on select environmental surfaces, including hot dogs (25 and 125 g), salmon (25 g), deli turkey (25 and 125 g), cottage cheese (25 g), chocolate milk (25 mL), vanilla ice cream (25 g), queso

03/10/2019