Use of Microbial Data for Hazard Analysis and Critical Control Point Veri®Cationðfood and Drug Administration Perspective

810

Journal of Food Protection, Vol. 63, No. 6, 2000, Pages 810±814

Use of Microbial Data for Hazard Analysis and Critical Control Point Veri®cationÐFood and Drug Administration Perspective

JOHN E. KVENBERG* AND DARRELL J. SCHWALM

Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, HFS-601, 200 C Street S.W., Washington, D.C. 20204, USA

MS 99-501: Received 3 September 1999/Accepted 4 February 2000 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/6/810/1673832/0362-028x-63_6_810.pdf by guest on 24 September 2021

ABSTRACT

This paper examines the role that the microbiologist and microbiological testing play in implementing hazard analysis and critical control point (HACCP) programs. HACCP offers a more comprehensive and science-based alternative for controlling food safety hazards compared with traditional sanitation programs based upon good manufacturing practices. Con- trolling hazards under an HACCP program requires a systematic assemblage of reliable data relating to the occurrence, elimination, prevention, and reduction of hazards. These data need to be developed in a transparent environment that will ensure that the best scienti®c methodologies have been employed in developing the needed data. The two mechanisms used in HACCP to assess the adequacy of the database are validation studies and the veri®cation assessments. Microbiological testing is an important mechanism for collecting data used in developing and implementing an HACCP plan. Microbial sample data can help establish standard operating procedures (SOPs) for sanitation, assess the likelihood of the occurrence of hazards, establish critical limits, and assess the validity of the HACCP plan. The use of a performance standard to assess whether microbiological hazards have been reduced to an acceptable level creates an especially important use for microbial analysis. Microbial testing is also useful in implementing an HACCP plan by helping to monitor the effectiveness of sanitation SOPs, the compliance of incoming ingredients with safety criteria, the safety of product being held for corrective action, and the safety of the ®nished product. The veri®cation audits demonstrate that all control measures have been applied as designed in the HACCP plan. Although auditing HACCP records is the primary means of veri®cation, microbial sampling can play an important role as well.

The food-manufacturing industry has historically re- processing control measures to determine whether a partic- lied largely upon experience from consumer complaints, ular hazard should be controlled under the ®rm's prereq- product recalls, and reports of illnesses; general scienti®c uisite programs or under the HACCP plan. The following studies; and common sense manufacturing practices to de- is an example cited in the Food and Drug Administration's termine the best methods to use in controlling food safety (FDA's) ``Second Interim Report of Observations and Com- hazards. As more and more manufacturers begin to de- ments'' on the HACCP Pilot Program (3): velop hazaard analysis and critical control point (HACCP) One example encountered during the pilot program in- systems to control food safety hazards, the traditional roles volved a bakery product. The hazard analysis determined of the food microbiologist and microbial sampling are it is reasonably likely that the raw ingredients could contain being re-examined. Speci®cally, ®rms implementing an microbial hazards. During the processing, the product is HACCP program often ®nd that they need: enhanced baked in order to produce a product of a quality that can methods to identify and prioritize hazards to control, and be marketed. Studies conducted of the internal temperatures updated criteria for selecting control measures and select- during baking showed that the baking processing step is ing the operation parameters that will yield the most ef- lethal to any microbial hazard. The studies also showed that fective results. any product that was incompletely baked to such an extent Firms are willing to make these changes because the that the microbial hazards might survive would be too advantages of having a more detailed, science-based and doughy on the inside to undergo a further processing step process-speci®c hazard analysis, as well as scienti®c vali- and would not be suitable for marketing. dation and veri®cation data to document the adequacy of a The microbiologist plays a key role in developing and control system, quickly becomes apparent when adopting conducting such studies, as well as other studies that are in- an HACCP program. strumental to the proper implementation of an HACCP plan. Enhancing food safety controls often necessitates that a manufacturer conduct in-house scienti®c studies of their CHANGING ROLE OF MICROBIOLOGICAL TESTING

* Author for correspondence. Tel: 202-205-4180; Fax: 202-205-4121; An important goal of HACCP is to help the food pro- E-mail: [email protected]. cessor build safety into the process through a small number J. Food Prot., Vol. 63, No. 6 USE OF MICROBIAL DATA FOR HACCP VERIFICATION 811 of key or critical control measures that prevent, eliminate, found in its HACCP Pilot Program (2) that most ®rms try or reduce hazards to acceptable levels. An HACCP program to maximize the use of their prerequisite programs to con- shifts the focus of controls toward monitoring in-process trol hazards in order to avoid the strict requirements of the preventive control measures. At the same time there is a controls associated with a critical control point (CCP). FDA diminished focus on monitoring the quality of the ®nished reported in its ®rst Interim Report that ``in some instances, product. This shift in focus also changes the role of micro- the same type of hazards were controlled under the prereq- bial testing. HACCP substantially reduces the need to test uisite programs at one ®rm and under the HACCP plan at the ®nished product for the purpose of assessing the safety another ®rm.'' Either approach was effective as long as the of individual lots of product. prerequisite programs were well documented with standard This shift in focus is important because of the increased operating procedures (SOPs), were fully implemented, and awareness of the shortcomings of microbial testing of ®n- included monitoring records and veri®cation procedures. ished products. Reliance on end-product testing is particu- These veri®cation procedures typically included microbial larly inef®cient and ineffective when a large sample size testing. One ®rm, for example, utilized environmental sam- Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/6/810/1673832/0362-028x-63_6_810.pdf by guest on 24 September 2021 and high frequency of sampling is needed to provide sta- pling extensively to monitor cleaning and sanitizing of tistically reliable data. The reliability of ®nished product food-contact surfaces and potential sources of environmen- test data is especially poor when trying to detect a pathogen tal contamination such as ¯oor drains. The sampling plan that occurs in low numbers, occurs sporadically, and orig- was designed with the purpose of ®nding hidden areas that inates from an unknown source using unidenti®ed path- harbored microorganisms. This sampling plan required ways. As FDA reported in the Federal Register (1): greater ingenuity and the type of special knowledge that a End-product testing does not address the root causes microbiologist can bring to an HACCP team. of food safety problems; it is not preventive by design and The role of microbial testing in conducting a hazard requires that a large number of samples be analyzed to en- analysis. The development of an HACCP plan starts with sure product integrity. the identi®cation of the hazards that are reasonably likely MICROBIOLOGICAL TESTING IN AN HACCP to occur and to cause illness or injury in the absence of SYSTEM control. The National Advisory Committee on Microbio- logical Criteria for Foods explains in its ``HACCP Princi- An HACCP plan provides a safety-net of preventive ples and Application Guidelines'' (adopted 14 August measures to control hazards. The purpose of microbial test- 1997) (4) that during the hazard analysis, a ®rm must eval- ing is to con®rm that all possible avenues of contamination uate the severity of a potential hazard and its likely occur- have been identi®ed and that these avenues are being con- rence. A microbiologist can help the HACCP team assess trolled. To accomplish this, an HACCP program often a number of factors that can in¯uence the likelihood of changes the role of the microbiologist, and the location, occurrence of a hazard and the safety of a food product. timing, and frequency of sampling. Each of these changes These factors include water activity, pH, use of preserva- will be brie¯y discussed in order to provide a basis for a tives, and time and temperature pro®les. more detailed discussion of the role that microbial testing The FDA found during its HACCP Pilot Program that plays in validating and verifying an HACCP plan. the hazard analysis is often one of the most challenging The Microbiologist as a member of the HACCP steps in developing an HACCP plan. Normally an HACCP team. A ®rm's food microbiologist needs to be part of the team will develop a long list of potential hazards during HACCP team because of their speci®c knowledge and ex- the initial brain-storming phase of the hazard analysis. The pertise regarding hazard assessment, food safety control, team must then evaluate each potential hazard to determine and monitoring. They can contribute to the multidisciplin- which hazards merit being addressed in the HACCP plan. ary composition that is needed for an effective team and Firms often lack suf®cient data to determine whether a haz- for a team that will have the respect and con®dence of ard is likely to occur and whether the potential injury or management. For ®rms that must control microbiological illness that might result is severe enough to warrant a con- hazards, the microbiologist should be one of the team mem- trol measure being applied. As a result, many of the ®rms bers that receive speci®c HACCP training. The importance involved in the FDA HACCP pilot program found they of this was emphasized by several of the ®rms participating needed to design and conduct studies to assess these factors. in FDA's HACCP Pilot Program (2). In FDA's ®rst ``Interim These studies normally include microbiological testing if a Report of Observations and Comments,'' it was reported microbial hazard is being assessed. that ``training of employees is instrumental to their success Incoming ingredients. One common area where ad- and attitude . . . (it) seems to empower employees . . . and ditional studies are often needed concerns the assessment employees know the importance of their job and what to of hazards in incoming ingredients. Firms participating in do if there is a problem.'' HACCP training will also allow the pilot program reported that an important means of lim- the microbiologist to play a role as a person quali®ed to iting the number of hazards to be controlled is to use raw validate a ®rm's HACCP plan under FDA's HACCP rules. ingredients and materials that are free of hazards. All of the The role of microbial testing in the prerequisite pro- ®rms developed controls for incoming ingredients that had grams. Microbial testing of the processing environment can the affect of extending control of hazards backward in the be an important component of an HACCP program. FDA food production chain to the primary producers and sup- 812 KVENBERG AND SCHWALM J. Food Prot., Vol. 63, No. 6 pliers. Controls using microbial testing include: Certi®cates matter or microorganisms remain on surfaces that have of Analysis for selected contaminants, in-house laboratory been cleaned and sanitized. The assemblage of these types samples to con®rm acceptability, quick tests of indicator of sampling data can be another important component of parameters to assess acceptability, and screening of new the ®rm's monitoring efforts. At least one ®rm participating vendors including sampling by outside laboratory. in the FDA's HACCP Pilot Program used such sample re- For example, three of the pilot ®rms listed the patho- sults as a criterion for an incentive and reward program for gens Salmonella spp., Escherichia coli O157:H7, and Lis- clean-up crews. teria monocytogenes as potential microbial hazards that Use of microbial tests in a corrective action pro- may be present in incoming ingredients such as pasteurized gram. When there is a deviation from a critical limit, the milk, cheese, whey powder, and other dairy products. In affected product needs to be segregated and corrective ac- the course of developing and validating their HACCP plans, tions taken. It is preferable that the required corrective ac- these ®rms conducted in-house studies to assess the signif- tion be developed in advance and be speci®ed in the icance of contamination from these incoming ingredients. HACCP plan. However, FDA's HACCP rules provide a pro- Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/6/810/1673832/0362-028x-63_6_810.pdf by guest on 24 September 2021 They also required testing by their suppliers to assess the cessor with the option of holding and evaluating product adequacy of the control measures being applied by the sup- on a case-by-case basis. In these situations a ®rm needs to pliers to eliminate or prevent survival and growth of the make two types of assessments. First, an assessment is pathogens. These ®rms eventually decided, based upon made concerning the immediate action required to identify their test results and the absence of reported problems in and control any product affected by the deviation from crit- the scienti®c literature, that these pathogens were not likely ical limits. Once the product is controlled and segregated, to occur and need not be controlled in the HACCP plans microbial testing may be helpful in assessing the safety of as a CCP. Nevertheless, the ®rms also decided that because a product that deviates from critical limits. However, mak- E. coli O157:H7 has a high tolerance to low pH environ- ing such an assessment is subject to the same dif®culties ments and because there had been reported problems from discussed earlier regarding end-product testing. The second cross-contamination and recontamination of processed type of assessment concerns the integrity of the HACCP products from Salmonella and Listeria, that microbial data plan. When a deviation occurs, a ®rm evaluates whether the would continue to be collected for use in periodic revali- HACCP plan is properly designed to control the hazard dations of the hazard analysis. encountered. There may be a role for microbial testing in The use of microbial testing as a monitoring tool. this type of assessment, as well. Generally it is not feasible to use microbial testing to mon- Use of microbial testing in validating the HACCP itor critical control points because: results of tests for path- plan. Microbial testing can play a major role in a ®rm's ogens often cannot be obtained in a timely manner, and validation studies if microbiological hazards are being con- establishing a sampling schedule to detect pathogens that trolled by the HACCP plan. There are two types of vali- occur at low levels and on a sporadic basis may require a dation studies and each may include microbial testing. First, level of frequent sampling that is too costly and time con- a processor must conduct an initial validation of the suming. HACCP plan to determine whether the plan is scienti®cally It may also be dif®cult to use indicator organisms as a and technically sound: all hazards that are reasonably likely monitoring tool because of the problem of determining to occur have been identi®ed, and the control measures and what are appropriate levels to use as critical limits. Critical the critical limits will effectively control the hazards. limits are used to determine when a deviation occurs that The type of activities that are needed to perform an requires corrective action. initial validation include: a review of the scienti®c docu- Monitoring a CCP that controls a microbial hazard is mentation used to develop the HACCP plan; a review of normally accomplished by using indirect methods of mea- the scienti®c literature for other studies demonstrating that surement. Indirect measurements may include, for example, control measures are effective and critical limits are appro- measuring the temperature at which the food is held and priate; a review of any challenge studies, such as for pas- the time held at a particular temperature rather than testing teurization units, used to determine the limits of the pro- for the presence of pathogens or growth of microorganisms. cessing equipment and the parameters that need to be set Indirect measurements are also commonly used to monitor to achieve effective results; and a review of product testing incoming ingredients. If fresh unpasteurized orange juice is and other in-plant evaluation records that con®rm that mi- being used as an ingredient, for example, it may not be crobial hazards are being adequately controlled. feasible to test a lot for pathogens and wait for results be- If standard industry control measures or other widely fore using the product. Instead, manufacturers normally rely accepted measures are used, data in the scienti®c literature upon periodic inspections of the supplier, assurances from can be used to document that the control measures and the supplier that proper controls were applied on a lot-by- critical limits are effective. If unconventional or unique lot basis, and an inspection of the containers to assess their control measures and/or critical limits are used, scienti®c integrity. studies need to be conducted by the ®rm to demonstrate Microbial testing also can be used to monitor the ef- their effectiveness. These studies need to include microbial fectiveness of sanitation SOPs especially with respect to testing if a microbiological hazard is being controlled. cleaning operations. Rapid tests can detect whether organic Designing a microbial study involves careful planning. J. Food Prot., Vol. 63, No. 6 USE OF MICROBIAL DATA FOR HACCP VERIFICATION 813

The effectiveness of an HACCP plan is measured by the when a ®rm experiences an HACCP system failure, when extent to which each hazard is eliminated, prevented from deviations from critical limits occur on a regular basis, or occurring, or reduced to acceptable levels. This is normally when there are signi®cant changes in the product, process, relatively easy to assess if the food-manufacturing process- or packaging. The FDA's experience with the HACCP Pilot es include a kill step. In these cases, microbial testing can Program provided examples of situations that required re- con®rm that the kill step achieves 100% elimination under validation studies. In one instance a ®rm found that their the most adverse conditions expected. critical limits for incoming ingredients were routinely ex- For food-manufacturing processes without a kill step, ceeded. They determined that their limits for aerobic plate especially those involving raw agricultural products where counts and total coliforms were set to control quality pa- pathogen contamination cannot be effectively eliminated or rameters rather than safety parameters. The HACCP plan prevented, designing a validation study is often more com- was re-evaluated and the critical limits were changed so plicated. In these instances the manufacturer needs to apply that aerobic plate counts and total coliforms were used as control measures that will reduce the pathogens to accept- operational limits, and fecal coliforms and pathogens were Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/6/810/1673832/0362-028x-63_6_810.pdf by guest on 24 September 2021 able levels. This usually involves the application of a per- used as the critical limits. formance standard that de®nes the acceptable level of re- The need for revalidation studies also applies to the duction. If the process has one control measure that will prerequisite programs. Such studies are needed to evaluate achieve the entire reduction required, then the study design whether prerequisite controls are effective in providing the is simpli®ed. However, if the processor is relying upon a level of control and prevention that is required for the series of control measures that result in a cumulative re- HACCP plan to be effective. duction, the validation study design will likely be more The role of microbial testing in verifying the complicated. Some of the issues that arise in designing a HACCP plan. The HACCP provision for veri®cation revalidation study include: whether to use a surrogate organ- quires that a processor determine and document that all ism for an in-plant study; whether to use pathogens in a control measures have been applied as designed in the pre- laboratory study that duplicates in-plant controls; which requisite program SOPs and the HACCP plan. The tradi- control measures are critical to achieving the needed level tional view is that veri®cation normally does not need to of reduction; whether the reduction provided by each con- include microbial testing because, in large part, veri®cation trol can be measured separately; and whether the overall is accomplished by reviewing HACCP monitoring records. reduction provided by the control can be measured collec- The National Advisory Committee on Microbiological Cri- tively. teria for Foods guidelines support this view and advise in Recent studies conducted by several fresh citrus juice the section on veri®cation that: An effective HACCP sys- manufacturers provide examples of the important role that tem requires little end-product testing, since suf®cient val- microbial testing plays in validating processing controls. idated safeguards are built in early in the process. There- These ®rms used recognized consulting laboratories to de- fore, rather than relying on end-product testing, ®rms sign studies that involved both laboratory simulations using should rely on frequent reviews of their HACCP plan, ver- pathogens and in-plant con®rmation studies using surrogate i®cation that the HACCP plan is being correctly followed, organisms. Pathogens studied included several strains of E. and review of CCP monitoring and corrective action re- coli O157:H7 implicated in illness outbreaks, as well as cords. Salmonella strains. Control measures tested to simulate in- Neither FDA's Seafood HACCP rule nor the proposed plant operations included a variety of sanitizers as well as Juice HACCP rule requires any microbial testing, although steaming, washing, brushing, culling, and waxing. Studies it is recommended. were also conducted to examine the impact of juice extrac- Nevertheless, FDA's HACCP Pilot Program con®rms tion equipment on the micro¯ora of the juice. that many processors have extensive environmental and Similar studies are currently being conducted by the product-testing programs, and that microbial testing often apple cider industry and other parties interested in apple plays an important role in HACCP veri®cation. Firms par- cider production including academia and government ticipating in the pilot program report several ways to use groups. The FDA, for example, is conducting research at a microbial testing in a ®rm's veri®cation program. These in- cider processing facility in Placerville, Calif., and at its clude the following. MOFFETT and CFSAN microbiology laboratories. The research includes microbial studies to examine: the sources Veri®cation of prerequisite programs. Microbial of contamination in the orchards and processing facility; sampling is commonly used to verify that the sanitation the microbial ¯ora associated with different types of apples operations are effective. Typically, samples are taken from including tree-picked and drops; the microbial build-up in food contact surfaces to assess cleaning and sanitizing the processing operation under normal and adverse pro- SOPs, from environmental surfaces including ¯oor drains cessing conditions; and the effectiveness of a variety of to assess environmental cleaning programs, and of the prod- processing controls including sanitizers, washing, brushing, uct at the market level to assess retail storage controls and hot dips, steam, ozone, UV treatment, and warming±freez- shelf-life. Records are kept of the sample results and fol- ing±thawing regiments. lowup corrective actions are taken if elevated microbial lev- The second type of validation is the as needed or at els are found. These records are reviewed under the ®rm's least annual reassessment studies. Revalidation is needed daily HACCP record audit procedures. The results are also 814 KVENBERG AND SCHWALM J. Food Prot., Vol. 63, No. 6 reviewed monthly as part of the assessment of the veri®- lowup and corrective actions if a positive sample result is cation procedures and yearly as part of the annual reas- obtained. The analysis of samples may need to be con- sessment. ducted before the product is shipped so the ®rm will not be placed in the position of needing to conduct a recall if Veri®cation of monitoring and corrective action re- a product is found to contain a pathogen. The ®rm also cords. Microbial testing is often used to verify that incom- needs to recognize that a regulatory agency will be inter- ing ingredients have been subject to effective controls. This ested in any sample results that indicate a hazard in the testing includes in-house samples collected by the processor product. The ®rm will need to document what actions were and tests results provided in Certi®cates of Analysis by the taken to keep any unsafe products out of the market place supplier. Microbial testing is also used to verify that a lot and that the source of the problem was investigated and of product that is segregated when a critical limit is not corrected. met, meets, or does not meet food safety criteria. CONCLUSION HACCP system veri®cation. Microbial test results are Downloaded from http://meridian.allenpress.com/jfp/article-pdf/63/6/810/1673832/0362-028x-63_6_810.pdf by guest on 24 September 2021 normally tabulated and analyzed to identify any trends that HACCP has created the need for important changes in indicate whether or not sanitation and HACCP controls are the role of the microbiologist and microbial testing in the being effectively applied. Firm management can also use food industry. Under an HACCP program, the microbiol- microbial test data tabulations to verify to buyers, upon ogist is a key member of a ®rm's HACCP team and an request, that a safe product is being produced. Finally, ®rms active participant in developing the HACCP plan. The mi- that have in-house microbiological testing capabilities rou- crobiologist plays a lead role in designing microbial studies, tinely perform quality assurance analyses to verify that developing monitoring strategies, and generating validation standard procedures are being followed in the laboratory. data to help the HACCP team assess the effectiveness of Although there are advantages to incorporating micro- the processing controls being used. When the team deter- bial testing into a veri®cation program, there are also some mines that improved controls are needed, the microbiologist issues that arise if this is done. The ®rst issue regards the can help develop the scienti®c justi®cation needed for man- sampling plan and analytical method. A ®rm must decide agement to understand, fund, and adopt the improvements. what samples are to be taken, what type of tests are to be In many instances these enhanced responsibilities increase conducted, and for what organisms are the tests to be con- the challenge and rewards of the microbiologist's job. ducted. The sampling plan is important because pathogens REFERENCES often contaminate a food sporadically, and it is not practical to sample large quantities of the product. The degree of 1. Food and Drug Administration. 1994. Food and safety assurance pro- con®dence that can be placed upon the sample result is gram; development of hazard analysis critical control point; proposed dependent upon the sampling plan that is chosen. rule. Fed. Regist. 59:149. 2. Food and Drug Administration. 1996. Hazard analysis and critical The analytical method is important because it deter- control point (HACCP) pilot program for selected food manufacturers. mines whether samples will be analyzed for pathogens or Interim report of observations and comments, 19 June 1996. indicator organisms. Normally, sanitation and in-line pro- 3. Food and Drug Administration. 1997. Hazard analysis and critical cess samples are analyzed for indicator organisms. If indi- control point (HACCP) pilot program for selected food manufacturers. cator organisms are used, guidelines need to be established Second interim report of observations and comments, 31 October 1997. as to what levels indicate a problem that requires followup 4. National Advisory Committee on Microbiological Criteria for Foods. and corrective action. If samples are analyzed for patho- 1997. Hazard analysis and critical control point principles and appli- gens, guidelines need to be established by the ®rm on fol- cation guidelines. 14 August 1997.