USDA DRAFT, March 2005 Risk Assessment of the Impact of Lethality Standards on Salmonellosis from Ready-to-Eat (RTE) Meat and Poultry Products

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USDA DRAFT, March 2005Risk Assessment of the
Impact of Lethality Standards on Salmonellosis
from Ready-to-Eat (RTE) Meat and Poultry
Products
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Risk Management Issue

• USDA/FSIS has proposed regulations for processors
  to achieve a specified level of lethality in the
  processing of RTE meats and poultry
• Specification in terms of probability of survival
  of Salmonella (log reductions) when present in
  raw materials

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• The proposed RTE rule has a minimum lethality of
  a 6.5 log reduction of Salmonella in meat for all
  categories (cooked, fermented, salt-cured,
  dried).
• Question for Risk Assessment
• What would be the public health impact of
  alternative lethality standards of 5.0-log and
  6.5 log of Salmonella (7.0-log for products
  containing poultry)?

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Scope

• Estimation of cases of salmonellosis only
  (although other pathogens affected also)
• Sources other than raw material contamination not
  measured (i.e., post-processing contamination
  during packaging, retail or home handling
• Given the charge other pathways of contamination
  do not significantly alter the determination of
  the lethality standard

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A first step

• Many products/processes to consider
• Categorization/groupings of products needed

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Risk category assignment

• Fully cooked, uncured, non-shelf-stable
• Fully cooked, cured, non-shelf-stable
• Fermented, uncooked, shelf-stable
• Dried (including heat treatment)
• Dried, no heat treatment (salt-cured)

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Risk factors

• 1. Primary Control Mechanism
• Thermal processing
• Fermentation (direct acidification) thermal
  processing
• Fermentation (direct acidification)
• Thermal process water activity
• Water activity

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Risk factors

• 2. Controllability
• degree of control in ability to manage the
  primary control mechanism
• 3. Role of formulation in lethality
• E.g., not critical in fully cooked product,
  critical in uncooked, fermented product
• 4. Relative margin of safety
• Large for cooked product, variable or small for
  uncooked
• 5. Re-growth of pathogens
• Growth, controlled, no growth

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Risk factors

• 4. Relative margin of safety
• - Large for cooked product, variable or small
  for uncooked
• 5. Re-growth of pathogens
• Growth, controlled, no growth

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Product risk categories

• Roast beef, corned beef
• Fully cooked beef patties
• Cooked pork (ham, barbecued)
• Cooked turkey non-deli
• Cooked chicken non-deli
• Cooked poultry deli
• Cooked chicken patties
• Beef/pork frankfurters

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Product categories

• Beef/pork bologna
• Poultry frankfurters
• Semi-dry fermented sausage
• Dry fermented sausage
• Meat sticks
• Beef jerky
• Country ham
• Prosciutto, Cappicola, Pancetta, Basturma

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Risk Estimation Evidence

• Factors
• Level of contamination of raw materials
• Required level of lethality standard
• Extent of compliance with standard
• Thermal processing safety factors (re any
  thermal lethality process)
• Storage of product and potential growth of
  surviving organisms
• Frequency and extent of consumer re-heating of
  product
• Amount of consumption of product

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Data sources

• Microbiological baseline surveys
• Raw material pathogen burden
• Prevalence and concentration
• Industry practices
• Formulation, safety factors, etc.
• Consumer surveys
• Expert opinion
• Predictive growth models
• Economic census (production volumes)

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Exposure Pathway
Raw Material Contamination
Lethality Impact
Compliance Level
Thermal Process Safety Factor
Storage and Growth
Reheating
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Hazard Characterization

• Dose-Response model from FAO/WHO risk assessments
  for Salmonella in broiler chickens and eggs
• Beta-Poisson model

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Salmonella D-R Model Based on Outbreak Data
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Risk characterization

• Surviving pathogens from raw materials (including
  expected growth after processing)
• Probability of illness from surviving pathogens
• Consideration of sensitivity of model to
  assumptions about risk factors and data inputs

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Results

• Risk of illness per 1000 Kg
• To identify products of highest risk per unit of
  food
• Number of cases per year
• Influenced by amount of each product category
  that is consumed each year in the USA
• contribution of each product category to total
  number of cases

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Rationale

• A product of highest risk per unit of food may
  cause only a small number of cases if total
  amount consumed by population is small
• A product of low risk per unit may cause many
  more cases if a very large amount of product
  consumed

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Results Cases per year

• 5-log lethality standard applied to all products
• 66,000 case of illness
• Split processing lethality standard
• Cooked (6.5 logs for beef, pork 7.0 logs if
  contains poultry)
• Other (5.0 log logs)
• 1,900 cases of illness
• All 6.5 (7.0 for poultry) lethality
• 1,100 cases of illness

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Limitations and Uncertainties

• Categorization
• Pathogen Burden in Raw Materials
• Thermal Process Safety Factors
• Storage and Growth
• Consumer Reheating
• Dose-Response Relationship
• Measure Units for Consumption

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Risk management considerations for selecting a
standard

• What is the acceptable level of risk?
• 66,000 cases vs. 1,900 cases vs. 1,100 cases
• Feasibility of achieving risk reduction,
  including
• Ability of industry to achieve
• Maintaining product characteristics
• Ensuring compliance
• What is the cost to society?
• What is the cost to industry?
• Is more research/surveys needed to reduce
  uncertainty?

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Comments

• Available via internet
• USDA, Food Safety Inspection Service (FSIS)
• Office of Public Health Service, Risk Assessment
  Division
• Risk assessment model developed using software
  Analytica (Enterprise version 3.0).
• Model can be reviewed using Analytica Player
  downloadable from www.lumina.com (free-of-charge)

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Comments

• Revisions to draft risk assessment may be done
  after public comment
• All risk assessments should be considered dynamic
• New research, technology changes, new knowledge
  will help to improve