P3-03 Evaluation of Dry Transfer in the Removal of Salmonella from Food Contact Surfaces

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Siman Liu , Illinois Institute of Technology , Bedford Park , IL
Ian Hildebrandt , U.S. Food and Drug Administration , Bedford Park , IL
Stephen Burbick , U.S. Food and Drug Administration , Bedford Park , IL
Nathan Anderson , U.S. Food and Drug Administration , Bedford Park , IL
Elizabeth Grasso-Kelley , Illinois Institute of Technology , Bedford Park , IL
Susanne Keller , U.S. Food and Drug Administration , Bedford Park , IL
Introduction: Low-moisture food manufacturers frequently implement dry-sanitation practices to clean equipment. Consequently, the purge of production lines using inexpensive dry materials to remove microbial hazards, such as Salmonella, provides an attractive alternative to traditional wet-sanitation. However, the efficacy of such methods is in question, and methods to determine efficacy are not currently available.

Purpose: The goal of this study was to examine the efficacy of a dry-material purge in removing Salmonella from a variety of equipment materials.

Methods: A cocktail of five Salmonella serotypes was used to inoculate beads composed of seven different food contact materials (including several stainless steel and nonmetal materials) by submersion into the inoculum. Subsequent transfer rates to a wheat flour were determined by mixing three beads of each material type with one gram flour for 60 s, then removing the beads. Experiments were completed in triplicate beginning with fresh inoculum. Population values were statically compared using ANOVA.

Results: No significant differences (P>0.05) were found in the populations of Salmonella adhering to the beads, regardless of material. When transfer to flour was examined, significant differences were found between polypropylene and all types of stainless steel and Delrin; and between nylon, glass, Delrin, and two types of stainless steel (P<0.05). No significant differences were found between nylon, glass, Delrin, and 316 stainless steel precision (P>0.05).

Significance: Differences in Salmonella populations, recovered based on material types, indicated that Salmonella may adhere more tightly to plastics than to stainless steel or glass; making the latter materials more amendable to dry-material purge cleaning methods.