Ann Marie McNamara

The phrase “performance standards” has different meanings to different people. Some people, for example, equate performance standards with end-product testing and “zero tolerance” for pathogens. To achieve an unambiguous framework in which food safety management concepts are clearly understood and used, it is critical that the different definitions for performance standards and other types of microbiological criteria are used accurately and consistently.

The Institute of Food Technologists convened a panel of scientific experts to address this compelling issue. The outcome of the panel’s deliberations is the IFT Authoritative Report, “Managing Food Safety: Use of Performance Standards and Other Criteria in Food Inspection Systems,” that clearly characterizes the nature of performance standards and describes and clarifies their suitable use within a systematic approach to managing food safety.

The report, summarized here, presents definitions for the different types of microbiological and other food safety criteria, identifies effective use of performance standards at specific points in the food system, and shows how performance standards relate to Good Hygienic/Manufacturing Practices (GHPs/GMPs), the Hazard Analysis and Critical Control Point (HACCP) food safety management system, and Food Safety Objectives (FSOs). The document also presents a case study on a current issue—Enterobacter sakazakii in powdered infant formula—for which the need for a performance standard or other criterion has not yet been determined.

Definitions of Criteria
There are a number of different types and, hence, uses for microbiological and other food safety criteria. To clarify the different food safety criteria, advance uniformity in the use of the terms, and encourage international acceptance of one set of inter-related definitions, IFT presents a set of definitions, several of which were previously defined by other organizations, that all constituencies are encouraged to adopt.

Consistent and transparent use of food safety terminology and their definitions, across all sectors of the food system, would (1) enable food manufacturers to responsibly apply criteria, including performance standards, and regulatory agencies to effectively regulate and oversee food safety; (2) foster cooperative, complementary efforts among the industry and regulatory agencies; (3) contribute to harmonization among domestic and international food standards; and (4) enhance effectiveness of public outreach.

Historical Perspective
Food safety is assured primarily by controlling microorganisms at the food source and selecting suitable raw materials; designing products and controlling processes to ensure safety; applying GHPs/GMPs; and implementing HACCP. The establishment and application of a variety of criteria—from microbiological specifications to process criteria, performance criteria, product criteria, and performance standards—can be useful for defining the acceptability of raw materials, ingredients, products, and in some circumstances product lots. Criteria, which may be mandatory or advisory in nature, may also be useful in assessing the adequacy of food safety control measures throughout the food system from production to consumption.

Food safety criteria, including performance standards, have an evolutionary history in the United States. Following the link of typhoid fever to consumption of raw shellfish harvested from fecally contaminated waters and the development of microbiological detection techniques for Escherichia coli, specific bacteriological criteria were established and screening and certification of shellfish and their harvesting waters were initiated. Additional microbiological criteria for specific pathogens were established more recently. For example, the U.S. Department of Agriculture’s Food Safety and Inspection Service established in 1994 a zero-tolerance performance standard for raw ground beef following an outbreak of Escherichia coli O157: H7 in a fast-food restaurant that resulted in 700 illnesses and four deaths. FSIS issued in 1996 its “Pathogen Reduction and Hazard Analysis and Critical Control Point (PR/HACCP)” final rule, which established the agency’s Salmonella performance standard. And, in response to outbreaks associated with raw juices, the Food and Drug Administration’s Center for Food Safety and Applied Nutrition issued performance standards for juice manufacturers along with requirements for HACCP implementation.

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Effective uses of performance standards at specific points in the food system include the following examples:
• Performance Standards for Juices. Because of several occurrences of E. coli O157:H7 contamination in apple juice and pathogen-related concerns with other juices, FDA established a performance standard and HACCP implementation requirements for controlling this pathogen and other hazards to a designated level. The agency’s performance standard and HACCP rule do not require the use of any specific processing/treatment method for achieving the standard; thus, processors have flexibility in their design of suitable control measures.

The rule requires juice processors to use a process/treatment that will destroy 99.999% of the main pathogen of concern for the juice. Some operations/operators are exempt from this requirement, however. For example, foodservice operations or retailers who sell directly to consumers are not required to use such a treatment, but instead must place a warning label on their product stating “WARNING: This product has not been pasteurized and, therefore, may contain harmful bacteria that can cause serious illness in children, the elderly, and persons with weakened immune systems.”

The rule also requires processors to conduct end-product testing to verify the absence from the juice of E. coli. Biotype I (generic/non-pathogen used as an indicator) and, hence, treatment/processing adequacy. When sampling indicates that the process was inadequate (two out of seven consecutive samples are positive), the processor must then take corrective actions to achieve the required pathogen reduction.

• Performance Standards for Salmonella. In 1996, FSIS established performance standards for Salmonella to provide interim targets for reducing Salmonella contamination consistently over time in slaughter plants and in plants producing raw ground products. Meeting the performance standards is required of the plants as a condition of maintaining inspection. The standards allow plants the flexibility to devise their own optimal means of managing food safety. The performance standards, which focus on the process at slaughter and grinding, are not intended to assess individual lots of products for lot acceptance or release purposes. The agency uses the results to verify that HACCP systems are effectively controlling Salmonella contamination in the identified species and products. The standards compel the “above average” processors to reduce their Salmonella incidence level by whatever means necessary to achieve the standard.

FSIS reported that reduction in Salmonella incidence in meat and poultry regulatory samples (from 5.0% to 4.3% between 2001 and 2002) and reduction of foodborne illnesses by 16% between 1996 and 2002 is evidence that the PR/HACCP rule is working.

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A number of limitations, which are discussed more thoroughly in the report, present challenges for establishing and effectively applying performance standards. There are also a number of practical issues—ranging from process, technology, and quality, to economic constraints—which can have an impact on the implementation of performance standards.

• Data. Data provide the scientific backbone of risk assessment. Data are critical for advising and guiding risk assessment, and for providing the baseline information upon which a new or revised performance standard can be established. Data are also important for validating existing standards. Unfortunately, when data are available they are rarely adequate or complete. For this reason, data availability is one of the most important limitations in establishing and applying performance standards.

In many instances, industry databases contain a wealth of information (e.g., within quality assurance or product monitoring programs) that could be used in designing performance standards. Unfortunately, access to these databases remains an issue. Other data considerations exist as well. For example, because many food safety end points are “moving targets” (contaminant prevalence or level decreases as food safety control increases), determination of data-collection end-point and establishment of the associated outcome measurements can be complicated.

• Balancing Verification of Compliance with Testing Limitations. Once established, effective implementation of performance standards and regulatory compliance must be verified. Verification can be accomplished in several ways: inspection (either visual or via acceptance sampling/testing), statistical process control, or other process controls.

Inspection as a verification method, however, is impractical and ineffective. Inspection of even 100% of product may fail to recognize and condemn unacceptable product or, conversely, may inappropriately render an entire production lot useless (e.g., inappropriately condemning product during visual inspection). When 100% inspection is not possible (e.g., testing would destroy all of the product), acceptance sampling may be conducted; but acceptance sampling cannot detect pathogens or toxins that are concentrated in a very small portion of the lot or hazards that are present at very low levels. Also, sampling must be conducted in a manner that allows evaluation of the entire lot of product, and the number of samples must be sufficiently large to enable detection of the hazard or ensure its absence. Despite recent advances, microbiological testing continues to be an ineffective method of assuring safety.

As more effective control measures are adopted by industry and the prevalence of contamination decreases, a point is reached where product testing is no longer practical or justifiable. At that stage, greater benefit can be achieved by shifting verification procedures to comprehensive analysis of control systems that have been validated to control the pathogens of concern.

The reality remains, however, that any performance standard requires monitoring and/or testing of the process, the product, or both. There is clearly a need to ensure that monitoring and testing methods are appropriately validated (including assurance of adequate sampling methodologies; data management; laboratory methods; and equipment, facilities, and personnel).

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• Consumer Element. Because contaminants can enter the food chain at virtually any point from the farm to our tables, some responsibility for food safety is shared by individuals at each point throughout the food continuum, from farmers to consumers. Huge gradations exist, however, in risk perception and understanding of how to reduce risk. Despite increased public awareness and interest in food safety, unsafe food consumption and preparation behaviors have increased.

Behavior change is unlikely if people do not recognize and accept their role in food safety. Farmers, manufacturers, retail and foodservice professionals, transportation and distribution professionals, and consumers alike must understand and accept their own role in managing food safety. The scientific knowledge, technology, and equipment are not available to eliminate all microbial hazards from all foods. Thus, risk communication and public education about risk reduction are necessary, to provide consumers with an accurate perception of food safety risk and encourage behavior modification, where needed.

Achieving Public Health Goals
While there is no way to provide absolute safety in food products, management of risk to an appropriate level is possible and achievable. With information provided by risk assessors, the food industry, and consumers, it is possible to determine a maximum frequency or concentration of a microbiological hazard in food that would be considered appropriate in terms of consumer protection. This frequency or concentration can be translated into a definable goal—the FSO—for use in food safety management systems that incorporate GMPs and HACCP.

FSOs link information from risk assessment and management with processes designed to control the risks. This approach to risk management is preferred because focus is placed on protection of consumers while flexibility in the design of control measures is allowed. The FSO approach to food safety management is relatively new and evolving, but is gaining acceptance because it offers a practical means to convert public health goals into values or targets that can be used by regulatory agencies and industry.

As regulators move toward designing food safety regulations within the framework of risk assessment and FSOs, they are increasingly faced with the challenge of how to link public health goals with scientifically valid criteria such as performance standards. Quantitative performance standards can be used to achieve certain public health goals. They can also serve to verify the ability of process steps to control or reduce the concentration of pathogens of concern. Suitable criteria can include performance, process, or product criteria; in some circumstances the use of microbiological criteria is appropriate.

Some current food safety regulations (i.e., regulatory use of performance standards) mandate specific pathogen reductions through processing, but this approach does not necessarily ensure compliance with an FSO. For example, as described in IFT’s 2002 Expert Report, “Emerging Microbiological Food Safety Issues: Implications for Control in the 21st Century,” under the current system a performance standard may require a 5-log reduction in pathogen levels for a raw agricultural commodity (e.g., fresh juice) regardless of the initial baseline level of microorganisms. Although a food processor could design a system to achieve the required reduction (e.g., 5-log), the required reduction may not be sufficient for products having a high initial baseline level of pathogens (e.g., 108 microorganisms). With an FSO approach, however, the processor would calculate the necessary performance criteria based on the expected initial level of pathogens and would determine the control measures needed to effectively achieve the intended results (i.e., level of hazard that is appropriate or allowable in the final product).

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Is a Performance Standard for Infant Formula Needed?
The potential applicability of performance standards is a relevant consideration as scientists, public health officials, and regulators struggle with the challenges of emerging issues. The pathogen E. sakazakii is such an emerging issue. Foodborne illness outbreaks involving powdered infant formula used in neonatal intensive care settings have been linked to E. sakazakii. The pathogen has been associated with a variety of severe and life-threatening conditions, especially in neonates and infants.

With the considerations noted above, how should formula manufacturers and the scientific and regulatory communities address a potential need for microbiological criteria? Should a farm-to-table performance standard for powdered infant formula be established?

The report addresses such questions and concludes that reacting too quickly to the risk to infants being fed powdered formula by setting a scientifically invalid performance standard—while well intentioned—would be scientifically questionable and could create, in the minds of caregivers of at-risk infants, a false sense of lowered risk. Data collection, judgment of experts, documentation of the present situation, and a cooperative effort by all constituencies are the best actions to ensure a systematic approach to reduce the risk of further illness.

Science Must Be Central
Ideally, the regulatory and non-regulatory uses of criteria, e.g., performance standards, would be clearly delineated. Performance standards are only one part of a systematic approach to managing food safety. The systematic approach needs to begin at production and continue through processing and beyond, through distribution, transportation, and food handling and preparation. Everyone in the food system—from farmers and producers to preparers and consumers—shares responsibility for food safety. Depending on the food and the nature of the pathogen, however, greater responsibility may reside with one constituency than another. For example, with our current level of scientific knowledge and technological capabilities there may be little that can be done in production and processing to eliminate a pathogen (e.g., E. coli O157:H7), but much that can be done at the point of preparation to reduce the risk of illness.

Performance standards need to be based on scientifically validated and verifiable data, which must continuously be improved. Performance standards contribute to but do not guarantee safety. Likewise, microbiological testing can be used to validate and verify a process or critical control point, but cannot ensure safety. Final product testing has been historically misused to attempt solely to ensure the safety of a product defined by the performance standard. Misuse of microbiological testing can create mistaken confidence and a false sense of security on the part of food manufacturers, regulatory agencies, and consumers. Providing a safe food product is a complex process requiring process and product control throughout the entire food system. Multiple meaningful performance criteria may be necessary at different stages in the food system to achieve a desired FSO.

Many factors compete in food safety management and decision-making, but science must be central. Ultimately, “performance standards,” the current buzzword in some circles, are only one part of what must be a systematic approach to reducing the risk of foodborne illness—an approach that runs through the entire farm-to-table continuum.

How to Obtain the Report
The full 15-page report, “Managing Food Safety: Use of Performance Standards and Other Criteria in Food Inspection Systems,” is available on the IFT Web site at www.ift.org.

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Definitions of Food Safety Criteria
Food safety objective (FSO): The maximum frequency and/or concentration of a hazard in a food at the time of consumption that provides or contributes to the appropriate level of protection (ALOP).

Performance objective: The maximum frequency and/or concentration of a hazard in a food at a specified step in the food chain before the time of consumption that provides or contributes to an FSO or ALOP, as applicable.

Processing safety objective: The FSO minus any projected pathogen growth. If no pathogen growth is expected, the processing safety objective is the same as the FSO. Similar to a performance objective but more specific, a processing safety objective is used to develop the performance and process/product criteria and to establish verification and acceptance procedures.

Microbiological criterion: A microbiological criterion defines the acceptability of a product or food lot, based on the absence or presence or number of microorganisms, (including parasites), and/or quantity of their toxins/metabolites, per unit(s) of mass volume, area, or lot.

Performance criterion: The effect in frequency and/or concentration of a hazard in a food that must be achieved by the application of one or more control measures to provide or contribute to a performance objective or an FSO. This is specific to a given operation.

Performance standard: The degree to which a step or combination of steps in the production, processing, distribution, and/or preparation of a food must operate to achieve the required level of control over a hazard. This parameter is more focused than the performance criterion and, in certain instances, can be mandatory if incorporated into a law, regulation, or ordinance.

Both performance criteria and performance standards are used to meet FSOs. To assure that performance criteria and performance standards are achieved, the following additional criteria may be used:

Process criteria: The control parameters of a step, or combination of steps, that can be applied to achieve a peformance criterion.

Product criterion: A parameter of a food that can be used to assess the acceptability of a lot or consignment.

Microbiological guideline: An advisory criterion used to inform food operators of the microbiological content that can be expected in a food when best practices are applied.

Microbiological specification: Part of a purchasing agreement between a buyer and a supplier of a food; such criteria may be mandatory or advisory according to use.

Microbiological standard: A mandatory criterion that is incorporated into a law, regulation, or ordinance.

Authoritative Report Panel
Lee-Ann Jaykus
(Panel Chair), Associate Professor, Dept. of Food Science, North Carolina State University; Gary R. Acuff, Professor and TAES Faculty Fellow, Dept. of Animal Science, Texas A&M University; Frank F. Busta, Emeritus Professor, Dept. of Food Science and Nutrition, University of Minnesota; James S. Dickson, Professor, Dept. of Animal Science, Iowa State University; C. Ann Hollingsworth (IFT President 2003–04), Better Built Foods; John Marcy, Extension Food Scientist, Center of Excellence for Poultry Science, University of Arkansas; and Ann Marie McNamara, Vice President of Food Safety and Scientific Affairs, Silliker, Inc.

About the Author

Ann Marie McNamara, PhD, is vice-president, food safety and quality for supply chain, manufacturing and commercialization, US Foods.