Microbial Assessment of Leafy Greens and Leafy Greens Contact Surfaces in Retail Foodservice Operations

Introduction: With the increasing numbers of aging Americans, the emphasis on food safety “away from home” in retail foodservice operations that serve older adults has become paramount. Among the foods served, the safety of fresh produce items is of concern as leafy greens have been implicated in foodborne illness outbreaks and product recalls. Improper food handling in foodservice establishments is also major concern as it can lead to cross contamination and thereby illness.

Purpose: The objective of this study was to determine the food safety status of food contact surfaces and leafy greens handled at selected hospitals, restaurants, long term care facilities, and assisted living facilities in Kansas and Iowa.

Methods: Three leafy greens samples and three food contact surface samples were collected at four different types of foodservice operations in Iowa (n = 4) and Kansas (n = 4) as part of the food flow (receiving, handling and service). Microbiological analysis was contacted for presence/absence of Listeria monocytogenes, Escherichia coli O157, and Staphylococcus aureus using ELISA technology.  Enumeration for aerobic plate counts (APC), coliforms, and fecal coliform (FC) counts using petrifilm was performed.  Statistical analysis was performed using SAS program.

Results: All samples were negative for the pathogens tested. APC counts had significant difference for the type of sample (P < 0.05) with the leafy green samples having higher microbial counts than the surface samples (1.35-1.46 log CFU/g and 0.09-0.81 log CFU/cm², respectively). Coliform counts had significant difference between the types of operation, but at low levels (0-0.38 log CFU).  FC counts were not significantly different for the type of sample and the type of operation (0-0.08 log CFU).

Significance: These results indicate that foodservices serving the elderly are procuring safe produce and are performing safe food handling practices but further behavioral studies may provide additional insight on the food safety status within these settings.