# Presentation: 361050

## Dr. Neal Golden
USDA, Food Safety and Inspection Service
Office of Public Health Science
Risk Assessment Division 

- USDA, Food Safety and Inspection Service
- Office of Public Health Science
- Risk Assessment Division

- Introduction and Overview of the FSIS *Clostridium perfringens* in Ready-to-Eat and Partially Cooked Meat and Poultry Products Risk Assessment

## Overview

- Background
- Microbiology of *Clostridium perfringens*
- Epidemiology of *C.  perfringens *(CP) foodborne illness
- Summary

**Overview**

## Background

## Background

- During processing of Ready-to-Eat (RTE) and partially cooked foods (PCF), raw meat and poultry are heat treated (lethality step), then cooled in a process known as stabilization.
- Spores from pathogenic organisms, such as CP and *C*. *botulinum,* may be activated by the heat treatment and germinate into vegetative cells capable of growth.

## Background

- Current USDA stabilization performance standard (1999) states that no more than a maximum of 1 log10 growth of CP (a factor of 10) and no growth of *C. botulinum* is allowed during the production of processed meat and poultry products.
- In response to public comments on the proposed rule, *Performance Standards for the Production of Processed Meat and Poultry Products *[66 FR 12590; 2001], FSIS initiated the planning and development of this risk assessment.

## Microbiology of C. perfringens 

## C. Perfringens (CP)

- Gram-positive, spore-forming bacterium
- Anaerobic
- Non-motile
- Ubiquitous within the environment
- Optimal growth within meat and poultry products at 43-47 oC (109-117 oF).
- Type A, enterotoxin (CPE) positive CP, is the causative agent of *C. perfringens* foodborne illness.

## C. perfringens Pathogenesis

- Vegetative cell

- Developing
- Spore

- Toxin inclusion
- body

- Cell wall lysis

- Free
- Spore

- Free
- toxin

_**Food**_

_**GI tract**_

- Spore

- Heat

**High numbers of CP typically required to cause illness (10****7**** organisms)**

## Epidemiology of C. perfringens  foodborne illness

## Public Health Context

-  248,540 illnesses, 41 hospitalizations, and 7 deaths annually in the U.S. (Mead *et al*., 1999).

***C. botulinum***** has been estimated to cause:**
- 58 illnesses, 46 hospitalizations, and 4 deaths annually in the U.S. (Mead *et al*., 1999).

- Food vehicles most commonly associated with *C. perfringens* and *C. botulinum* food poisoning are meat and poultry products.

- During stabilization of RTE and PCF, CP and *C. botulinum* can grow in numbers and become potentially significant to public health.

## Disease Characteristics

- Symptoms include diarrhea, nausea, and abdominal pain.
- Incubation period ranges from 8 to 24 hours with symptoms lasting typically for 2-3 days
- Most illnesses are self-limiting, however, severity can vary.
- Severe illness and chronic sequellae are not associated with CP* * foodborne illness.

## C. perfringens Outbreaks

- The most common vehicles implicated in outbreaks of CP foodborne illness have been meat and poultry.
- Of the 153 CP outbreaks from 1990-1999, the majority were associated with meat and poultry prepared from _raw_ products (CDC, 2000).
- Only one outbreak has been confirmed as having been caused by an RTE product, turkey loaf (CDC 2000, DeWaal *et al*., 2001 ).
- The majority of CP outbreaks is associated with improper holding and occurs in institutional settings and (MMWR 1996, 2000).

## Criteria for CP Outbreaks (CDC, 2000):
Presence of 105 CP/gram in implicated food, or
Presence of 105 CP/gram in stool from two or more ill persons, or
Demonstration of enterotoxin (CPE) in stool from two or more ill persons.

Approximately 250 outbreaks involving 15,000 cases were reported to the CDC from 1990-2003.

- Presence of 105 CP/gram in implicated food, or
- Presence of 105 CP/gram in stool from two or more ill persons, or
- Demonstration of enterotoxin (CPE) in stool from two or more ill persons.
- Approximately 250 outbreaks involving 15,000 cases were reported to the CDC from 1990-2003.

*C. perfringens* Outbreaks

## Summary

## Summary

- CP is estimated to be the fourth most common bacterial foodborne illness in the U.S. (Mead *et al*., 1999).
- CP* and C. botulinum *foodborne illnesses are associated with meat and poultry products and could become a hazard from RTEs and PC products if stabilization is inadequate.
- To control the growth of CP, FSIS regulates the critical control limit of allowable CP growth at the processing plant.
- In response to public comment, the agency has developed and completed a risk assessment to evaluate the public health impact of the current USDA stabilization performance standard (1999).