Listeria monocytogenes (Lm )

Lm is a bacteria found in moist environments, soil, 

and decaying vegetation. It causes the foodborne 

illness, listeriosis.

Transfer of Lm from the environment, equipment, 

employees, or raw food is a particular hazard of 

concern in retail delis.

It can cross-contaminate food contact surfaces and 

foods. Improper sanitation, product handling, and 

employee practices can lead to the transfer of Lm to 

RTE meat and poultry products at retail.

Lm forms biofilms (thin layers of microorganisms that 

stick to product contact surfaces) that are difficult to 

remove from equipment and other surfaces.

Listeriosis

Serious infection can result from eating food 

contaminated with Lm.

Infection is rare, but could result in a high fatality rate 

(16% compared to 0.5% for Salmonella or E. coli

O157:H7).

It affects everyone, with older adults, pregnant women

and fetuses, newborns, children, and adults with 

weakened immune systems being at higher risk.

Flu-like symptoms can begin a few days after 

consuming contaminated products. However, invasive 

listeriosis, which can affect the central nervous system 

and may cause stillbirth or result in death, can begin 

up to 2 months after eating food contaminated with 

Lm.

There are an estimated 1,600 illnesses, 1,500 

hospitalizations, and 260 deaths in the U.S. each year.

Product Handling

It is important to adopt practices that protect RTE 

product from contamination with Lm (see bullets below

on ways to prevent or limit the growth of Lm in deli 

products). 

• Use products that contain antimicrobial agents or 

have received other treatments to eliminate or 

prevent the growth of Lm in RTE products. 

• Monitor and limit the shelf life of an RTE product 

that is opened, prepared, and held in a retail 

setting for more than 24 hours.

• Do not pre-slice products - product should be 

sliced at the time it is requested by consumers. 

• Remove products that are filthy, putrid, 

decomposed, slimy, rancid, or in off-condition from 

the deli area as soon as possible and thoroughly 

clean and sanitize areas that were contacted by 

such product to prevent any cross-contamination. 

• Promptly return RTE products to refrigerated units 

(at or below 41°F), after slicing, to slow pathogen 

growth. 

• Store and handle RTE products in separate areas 

from raw products. RTE products that are 

prepared, held, or stored near raw products can 

become contaminated (e.g., because of 

aerosolization or dripping).

A number of food safety 

practices are needed to control 

Lm contamination of retail foods.

Cleaning and Sanitizing

• Develop written sanitation procedures that 

describe how utensils and equipment (e.g., 

slicers) will be cleaned and sanitized prior to use.

• Clean and sanitize utensils and equipment used to 

handle, prepare, and store RTE products 

frequently (e.g., at least every 4 hours).

• Disassemble RTE food-processing equipment 

when cleaning and sanitizing to ensure that hard 

to reach areas where Lm can hide are addressed. 

• Scrub surfaces during cleaning to prevent biofilms 

from occurring. 

• Follow the manufacturer’s recommendations for 

sanitizer strength and application, including 

exposure time, to ensure it is effective. 

• Consider rotating sanitizers to provide more 

effective bacterial control. 

• Develop a procedure to sanitize cleaning aids

(e.g., cloths and scrub brushes) or have singleuse items that are discarded after use. 

• Use low water pressure when cleaning in the deli 

areas to minimize splashing and overspray. 

• Use separate sinks for hand washing and cleaning 

product or equipment.

• Eliminate or remove unnecessary items (e.g., 

supplies and equipment) from the deli area.
Employee Practices

• Train employees in sanitation practices and 

safe food handling procedures. 

• Ensure that employees wear gloves and 

change them as needed to prevent crosscontamination of RTE products.

• Provide adequate facilities, including soap and 

running water, and post instructions for 

employees to wash their hands. 

• Implement a policy to ensure that ill employees 

do not work with open food items, including 

RTE foods. 

• Limit employee traffic in the deli area and 

develop traffic-flow plans for product, 

employees, and other items to prevent 

contamination by consumers and employees. 

• Develop practices to prevent outer clothing 

from spreading contamination, such as wearing 

disposable aprons. 

For more information and a checklist of practices 

for your deli, go to FSIS Best Practices Guidance 

for Controlling Listeria monocytogenes (Lm) in 

Retail Delicatessens at

http://www.fsis.usda.gov/wps/wcm/connect/29d512

58-0651-469b-99b8-e986baee8a54/Controlling-LMDelicatessens.pdf?MOD=AJPERES

See the FDA Food Code, 2013, at: 

http://www.fda.gov/Food/GuidanceRegulation/Retail

FoodProtection/FoodCode/ucm374275.htm 

Additional information on Listeria is at 

http://www.fsis.usda.gov/wps/portal/fsis/topics/regul

atory-compliance/listeria

Facility and Equipment Controls

• Do not allow conditions in the retail facility that 

could cause the product to become contaminated. 

• Ensure that walls, floors, drains, and overhead 

structures in the RTE deli and cooler areas are 

smooth, durable, easily cleanable, and in good 

repair. 

• Do not perform construction (e.g., replacing floors, 

walls, or ceilings) when exposed RTE product is 

present in the deli. Thoroughly clean/sanitize the 

equipment and facilities after construction and 

before handling product.

• Maintain tables, slicers, and other food contact 

surfaces so that they are easily cleanable. 

• Clean overhead structures as often as necessary 

to keep them free of condensation and ensure that 

sanitary conditions are maintained. 

• Keep water from pooling on the floor or other

surfaces within the deli area. 

• Clean and sanitize surfaces between different 

types of RTE items (for example ham, seafood, 

and vegetables) when using the same equipment. 

• Ensure that grinders, dicers, scoops, or other 

equipment are maintained in sanitary condition. 

• Maintain product cases and storage at or below 

41°F to slow Lm growth.

USDA is an equal opportunity provider and employer.

United States

Department of

Agriculture

Food Safety and

Inspection Service

Guidance for Controlling

Listeria monocytogenes 

(Lm) in Retail 

Delicatessens

Best practice tips for deli 

operators 

The information in this brochure is taken from 

FSIS Best Practices Guidance for Controlling 

Listeria monocytogenes (Lm) in Retail 

Delicatessens. These are suggestions and 

not requirements.

Retailers should be aware that the 

recommendations in this guidance, especially 

those based on the 2013 Food Code may be 

requirements in State, local, or tribal 

regulations.