1. Cross Contamination Transfer Dynamics at Retail: Mock Deli Renee R. Boyer, PhD Virginia Tech Interagency Risk Assessment - L. monocytogenes in Retail Delicatessens Public Meeting Washington, DC - May 22 nd, 2013

2. Objective To identify significant cross contamination pathways in a retail deli that occur when contamination is introduced from different sites Using an abiotic surrogate, GloGerm™ lotion Study was funded by FSIS to provide data for the risk assessment Results have been published in peer reviewed journal: Maitland, J., R. Boyer, D. Gallagher, S. Duncan, N. Bauer, J. Kause and J. Eifert. 2013. Tracking cross contamination transfer dynamics at a mock retail deli using GloGerm. Journal of Food Protection. 76(2):272-282. 2 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

3. Layout of Mock Deli: 3 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

4. Materials and Methods: In each experimental trial: –one of six locations was contaminated (20ml GloGerm™) Deli slicer blade Floor drain Surface of deli meat chub Employees bare hands Employees gloved hands Preparation table surface –A series of standard deli operations was performed (~10 min) –Photographs of all contaminated surfaces were taken –Sensory panel was trained to quantify contamination 4 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

5. Deli Operations (performed in this order): Adapted from Lubran et al. 2010. Observational study of food safety practices In retail deli departments. J. Food Prot. 73:1849-1857. 5 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

6. A trained sensory panel was used to quantify presence and level of contamination –Coverage: the total area containing GloGerm™ –Intensity: the brightness of the GloGerm™ Material and Methods: 6 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

7. Ex. photograph of slicer shelf (the angled surface used to hold the meat chub level and steady before coming in contact with the blade) analyzed by the 8 panelists compared to control photograph (clean, no contamination ). In this photograph GloGerm TM contamination was initiated on the slicer blade. Eight panelists’s ranked photo 460 as having heavy contamination (2.75±0.46). 7 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

8. Materials and Methods: Panelists were asked to rank: –Contaminated surfaces compared to clean surface –Controls: initial inoculum levels; surfaces after cleaning; duplicate photos The one word rankings were converted to numbers none = 0, slight = 1, moderate = 2, heavy = 3 A mean contamination score was determined and then translated back into a descriptive value (rounded) Ex. 2.75 = heavy; 2.25 = moderate 8 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

9. Effect of starting contamination point on “overall spread” Recipient of Contamination Source of Contamination: Descriptive, Numerical Floor DrainGlovesBladeMeat ChubPrep TableHands Floor Drainsee next slidenone 0.00±0.00 a none 0.00±0.00 a none 0.00±0.00 a none 0.00±0.00 a none 0.00±0.00 a Glovesnone 0.00±0.00 a heavy 3.00±0.00 c slight 1.49±0.73 b moderate 2.06±0.57 c heavy 2.81±0.40 c heavy 2.94±0.25 c Bladenone 0.00±0.00 a slight 0.63±0.50 b heavy 3.00±0.00 d slight 1.00±0.00 b none 0.00±0.00 a none 0.00±0.00 a Meat Chubslight 0.94±0.25 a heavy 2.50±0.52 c moderate 2.13±0.62 c heavy 3.00±0.00 d slight 1.25±0.45 ab moderate 1.69±0.70 b Prep Tablenone 0.13±0.34 a moderate 1.88±0.34 c moderate 1.75±0.45 c moderate 1.88±0.45 c heavy 3.00±0.00 d slight 1.00±0.00 b Door Handlenone 0.38±0.50 a heavy 3.00±0.00 c slight 1.25±0.68 b none 0.38±0.50 a moderate 2.31±0.70 b none 0.13±0.34 a Within a row, means w/ different letters are significantly different based on nonparametric Behrens-Fisher test, P < 0.05. 9 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

10. Spread of contamination on the floor: (Key: ♦-slight, ♦♦-moderate, ♦♦♦-heavy,  -floor drain) 10 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

11. Additional locations contaminated: Recipient of Contamination Source of Contamination Floor DrainGlovesBladeMeat ChubPrep TableHands Hand wash sink faucet knobs 0 3 000 1 Top of glove box 0 3 000 3 Cart handles 0 2 0000 Scale face 0 21 000 Surface of interior deli case shelf 00 23 00 Bottom of prep table sink, near drain. 000 23 0 Slicer table near slicer 00 11 00 Bottom of employee shoes 3 00000 Cart Wheels 3 00000 11 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

12. Transfer of contamination to meat slices (third and ninth sliced consecutively) 1 Values within rows followed by the different letters are significantly different (based on the Behrens- Fisher test P < 0.05) Slice Number Source of Contamination: Descriptive 3, Numerical (mean±st. dev.) Floor DrainGlovesBladeMeat ChubPrep TableHands 3none 0.38±0.52 a moderate 2.38±0.74 c heavy 3.00±0.00 d heavy 3.00±0.00 d slight 1.25±0.46 b slight 0.63±0.52 a 9none 0.25±0.46 a Slight 1.38±0.52 b heavy 3.00±0.00 c slight 1.38±0.74 b moderate 1.50±0.53 b slight 1.13±0.35 b 12 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

13. Effect of starting contamination point on spread throughout the slicer: Recipient of Contamination Source of Contamination: Descriptive 2, Numerical 3 Floor DrainGlovesBladeMeat ChubPrep TableHands Bladenone 0.00±0.00 a slight 0.63±0.50 b heavy 3.00±0.00 c slight 1.00±0.00 b none 0.00±0.00 a none 0.00±0.00 a Bednone 0.43±0.51 a slight 0.50±0.52 a slight 1.38±0.50 a moderate 2.13±0.81 c slight 1.13±0.34 b slight 1.31±0.48 b Shelfnone 0.00±0.00 a slight 1.19±0.40 c slight 0.88±0.34 b heavy 2.88±0.34 d slight 0.63±0.50 b slight 0.88±0.34 b Handlenone 0.38±0.50 a heavy 2.88±0.50 c slight 1.25±0.45 b heavy 2.75±0.45 c heavy 3.00±0.00 c slight 1.25±0.45 b Carriagenone 0.00±0.00 a heavy 2.88±0.34 e moderate 1.75±0.68 c slight 1.00±0.52 b moderate 2.13±0.62 d slight 1.13±0.34 bc 13 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting

14. Conclusions Six originating sites were also generally the six most commonly contaminated from other surfaces –However, no contamination seen spread to the floor –Contamination spread to deli case door handle Highest degree of spread was from contaminated gloves Future research –Running similar trials with a mixture of fluorescing material and pathogen (or a biotic surrogate) 14 May 22 nd, 2013 Interagency Risk Assessment--Listeria monocytogenes in Retail Delicatessens Public Meeting