Listeria monocytogenes in the Retail Environment ©2006 Department of Food Science - College of Agricultural Sciences at Penn State University Penn State is committed to affirmative action, equal opportunity, and the diversity of its workforce. This publication is available in alternative media on request.

Sources of LM in the Retail Environment Listeria monocytogenes is ubiquitous Listeria monocytogenes is ubiquitous Potential sources include: Potential sources include: Food products Food products Environment Environment Equipment Equipment Employees Employees Customers or vendors Customers or vendors

Sources: Food Products Ready-to-eat foods Ready-to-eat foods Deli meats Deli meats Deli salads (including meat and seafood) Deli salads (including meat and seafood) Fresh soft cheese Fresh soft cheese Smoked seafood Smoked seafood Paté Paté Hot dogs Hot dogs Raw meats & poultry, raw seafood, vegetables, and fruits Raw meats & poultry, raw seafood, vegetables, and fruits

ProductPrevalence of Listeria monocytogenes (%) Fresh soft cheeses0.17 Bagged salads0.74 Blue-veined cheeses 1.42 Mold-ripened cheeses 1.04 Seafood salads4.7 Smoked seafood4.31 Luncheon meats0.89 Deli salads2.36 Prevalence of Listeria monocytogenes in RTE foods Gombas, D.E, Y. Chen, R.S. Clavero, and V.N. Scott Survey of Listeria monocytogenes in ready-to- eat foods. J. Food Prot. 66:

Sources: Environment Drains Drains Grease traps Grease traps Floors Floors Walls Walls Air vents Air vents Pests such as rodents and insects Pests such as rodents and insects

Sources: Environment Condensate Condensate Air movement Air movement Aerosols Aerosols

Sources: Equipment On equipment, LM has the ability to: On equipment, LM has the ability to: Colonize Colonize Multiply Multiply Persist Persist

Sources: Equipment Slicers Slicers

Sources: Equipment Wheels of carts that transport food from receiving Wheels of carts that transport food from receiving

Sources: Equipment Refrigerated storage units such as display cases and coolers Refrigerated storage units such as display cases and coolers

Sources: Equipment Cracks in preparation tables Cracks in preparation tables

Sources: Equipment Cooling fans in display cases Cooling fans in display cases

Sources: Equipment Other hard to clean areas Other hard to clean areas

Sources: Employees, Customers & Vendors Employees Employees Improper personal hygiene Improper personal hygiene Carriers of pathogen in intestinal tract Carriers of pathogen in intestinal tract Customers & Vendors Customers & Vendors Introduce LM into the store environment Introduce LM into the store environment Contact with employees or equipment Contact with employees or equipment

Causes of LM in the Retail Environment Improper sanitation Improper sanitation Poor personal hygiene Poor personal hygiene Improper time & temperature controls Improper time & temperature controls Cross contamination Cross contamination

Key LM Control Measures for Retail Environments Cooking Cooking Date marking Date marking Cold holding Cold holding Hand washing Hand washing Prevention of cross contamination Prevention of cross contamination