Preventing Introduction, Growth and Cross-Contamination of Listeria monocytogenes ©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.

Contamination Introduction Introduction –LM is brought into the facility from an outside source Growth Growth –LM present in the facility/food has the ability to multiply Cross-contamination Cross-contamination –LM present in the facility/food is transferred to another food or surface

Introduction of LM Employees Rodents/Pests Customers Vendors Contaminated Food Retail Facility Non-food items

Retail establishments are open to the public Retail establishments are open to the public Restrictions & controls should be designed to complement normal operations Restrictions & controls should be designed to complement normal operations

Introduction of LM Employees Employees –Sources  Ill employees  Unclean hands, clothing –Prevention  Good personal hygiene  Restriction of ill employees  Training

Introduction of LM Vendors Vendors –Sources  Ill vendors  Unclean hands or clothing –Prevention  Restriction from high risk areas  Training/vendor agreements

Introduction of LM Customers Customers –Sources  Ill customer  Unclean hands –Prevention  Facilitate proper handing of food –Tongs, single use paper –Instructions for proper handing

Introductions of LM Rodents/Pests Rodents/Pests –Sources  Feces  Rodents/pest carrying LM on feet and body –Prevention  Pest control program  Maintenance of indoor and outdoor facilities

Introduction of LM Contaminated Food Contaminated Food –Sources  Raw products (meat, poultry, fruits, vegetable)  Ready-to-eat foods –Prevention  Vendor assurances (HACCP plan, testing)  Vendor audits

Introduction of LM Non-food Items Non-food Items –Sources  Contaminated packaging, other supplies –Prevention  Receiving standards

Growth of LM Since it is not possible to eliminate all sources of LM in the retail environment, preventing growth is essential Since it is not possible to eliminate all sources of LM in the retail environment, preventing growth is essential –On Food –On Equipment –In the Environment

Controls to Prevent Growth 1. Adequate time and temperature controls 2. Proper cleaning and sanitation 3. Good personal hygiene

Time/Temperature Controls Cold Holding (Refrigeration) Cold Holding (Refrigeration) 41ºF for 7 days OR 45ºF for 4 days –LM can grow at refrigeration temperatures, so holding time is important –Control of LM growth is the basis for 2005 Food Code cold holding temperature/time combinations

Time/Temperature Control Date Marking Date Marking –Requires active managerial control –Applies to:  Certain high risk foods  Foods held for greater than 24 hours –After prepared by a food establishment –After opened, if a processed food

Estimated Reduction of Cases of Listeriosis from Limits on Refrigeration Temperatures Maximum Refrigerator Temperature Cases of Listeriosis a Media n 5 th Percentile 95 th Percentile Baseline b 2105¾c¾c ¾c¾c 7 °C (45 °F) maximum °C (41 °F) maximum a Values for the median, upper and lower uncertainty levels. b The baseline uses the full empirical distribution of refrigerator temperatures from the Audits International (1999) survey. c The baseline number of cases of listeriosis is fixed based on CDC surveillance data. Source: FDA/CFSAN and USDA Quantitative Assessment of Relative Risk to Public Health from Foodborne Listeria monocytogenes among Selected Categories of Ready-to-Eat Foods

Time/Temperature Controls Hot holding Hot holding –Minimum of 135ºF No temperature control No temperature control –Can be held for no longer than 4 hours at ambient temperatures

Cleaning & Sanitation Prevention of LM growth requires a sanitation program that is: Prevention of LM growth requires a sanitation program that is: –Properly designed –Properly carried out Target areas Target areas –Food contact equipment at room temperature at room temperature –Refrigerated storage & display cases display cases

Controls to Prevent Cross-Contamination Cleaning & Sanitation Cleaning & Sanitation Good Personal Hygiene Good Personal Hygiene Proper Flow of Food & Employees Proper Flow of Food & Employees

Cleaning & Sanitation To prevent cross-contamination To prevent cross-contamination –Always clean between working with raw and ready-to-eat products –Regularly clean to reduce chance that contaminated product transfers to uncontaminated product

Personal Hygiene Handwashing stations Handwashing stations –Easily accessible to promote frequent handwashing –Properly supplied Appropriate training Appropriate training –Employees should understand concept of cross-contamination

Proper Flow of Food Facility design Facility design –Separation of raw and ready-to-eat areas –Adequate storage and work space  Refrigeration  Preparation tables  Display cases

Flow of Employees Facility design Facility design –Location of hand washing facilities –Locations of locker & rest rooms –Separation of raw and ready-to-eat areas Designated tasks for employees Designated tasks for employees Designated work areas Designated work areas

Flow of Employees

Prevention of LM Prevent Prevent –Introduction –Growth –Cross-contamination