Notes: Chapter 7: Principle 3: Establish Critical Limits ...

1 Chap 7 - Principle 3: Establish Critical Limits73 ContinuedChapter 7: Principle 3: Establish Critical LimitsOverhead 1 Critical Limits must be established for each CCP identified in the 2 Overhead 3A Critical limit represents the boundaries that are used to ensure that anoperation produces safe products. Each CCP must have one or morecritical Limits for each food-safety hazard. When the process deviatesfrom the Critical limit, a corrective action must be taken to ensure foodsafety. Examples of Critical Limits are listed in Table Critical LimitsIn many cases, the appropriate Critical limit may not be readily apparentor available. Tests may need to be conducted or information gatheredfrom sources such as scientific publications, regulatory guidelines, expertsor experimental studies (Table 2).

2 Objective:In this module, you will learn: How to define Critical Limits . How to set Critical Limits for a CCP. How to find sources of Critical limit information. How to determine the relationship between Critical limitsand operating 3: Establish Critical : Critical Limit: A maximum and/or minimum value to which abiological, chemical or physical parameter must be controlled at aCCP to prevent, eliminate or reduce to an acceptable level theoccurrence of a food-safety :Chap 7 - Principle 3: Establish Critical Limits74 Overhead 4 Overhead 5If the information needed to define the Critical limit is not available,a conservative value should be selected. The rationale and referencematerial used to Establish a Critical limit should become part of thesupport documentation for the HACCP a variety of options exist for controlling a particular hazard.

3 Thecontrol options usually necessitate the establishment of different criticalTable 1. Examples of Critical LimitsHazardCCPC ritical Limitbacterial pathogenspasteurizer 161 F for 15 seconds for elimination of pathogens from milk(biological)bacterial pathogensdrying ovenDrying schedule oven temperature: 200 F, drying time:(biological) 120 min., air flow rate: 2 cuft/min, product thickness: (to achieve aw to to control pathogens in dried foods)bacterial pathogensacidificationBatch schedule product weight: 100 lbs., soak time: 8 hrs.,(biological)acetic acid concentration: percent, volume 50 gal. (to achievemaximum pH of to control Clostridium botulinum in pickled foods)Explanatory Note:These Critical Limits are forillustrative purposes only. Theydo not relate to any specificproduct but demonstrate howcritical Limits could apply atCCPs utilizing different controlparameters for bacterialpathogens.

4 In actual practice, Critical Limits must be scientifi-cally 2. Sources of Information on Critical LimitsGeneral SourceExamplesscientific publicationsjournal articles, food science texts,microbiology textsregulatory guidelinesstate and local guidelines, tolerances andaction levels ; USDA guidelines, tolerances andaction levels ; FDA guidelines, tolerances andaction levelsFDAFDA Fish and Fisheries Products Hazards andControls Guidance Manual (referenced inChapter 13)expertsNACMCF (National Advisory Committee onMicrobiological Criteria for Foods), thermalprocess authorities; consultants, foodscientists/microbiologists, equipmentmanufacturers, sanitarians, universityextension, trade associationsexperimental studiesin-house experiments; contract labsChap 7 - Principle 3: Establish Critical Limits75 Notes: Continuedlimits.

5 The selection of the best control option and the best Critical limitis often driven by practicality and experience. The following examplessuggest control options and Critical Limits that could be applied at thefryer step to control bacterial pathogens in fried fish 6 Setting a microbial limit as a Critical limit for an in-process CCP is rarelypractical. Microbiological Limits are difficult to monitor, and testing todetermine Critical limit deviations may require several days. Therefore,microbiological Limits cannot be monitored on a timely basis. Microbio-logical contamination is often sporadic, and samples may need to be largeto be meaningful. In this example, sampling and microbiological tests ofthe fish patties are unlikely to be sensitive enough or 7 Setting a microbial Critical limit is not necessary in this example as longas an appropriate Critical limit can be set that is based on the conditionsneeded to inactivate the microorganisms of concern.

6 Pathogens of concernin fish patties are destroyed by cooking the patties to an internal tempera-ture of 150 F for one minute. In this option, the product temperature at theend of frying is used as a Critical limit. This option is typically morepractical and sensitive than finished-product pathogen No. 1 Monitoring for PathogensHazard presence of pathogens (microbiological)CCP fryerCritical limit no pathogens detected(Not typically the best option)Option No. 2 Controlling Internal TemperatureHazard presence of pathogens (microbiological)CCP fryerCritical limit minimum internal temperature of 150 F for one minuteChap 7 - Principle 3: Establish Critical Limits76 Notes: Overhead 8In many cases, it is not practical to continually monitor the internaltemperature of the food product to ensure conformance with a criticallimit.

7 As an alternative, Critical Limits may be set that Establish conditionsnecessary to ensure that the cooking process achieves the necessaryminimum product temperature. In this option, the oil temperature, the fishpatty thickness and the time that the patty stays in the hot oil are allfactors that affect the final patty temperature. Tests must be performed toensure that controlling these factors within the Critical Limits will alwaysresult in an internal product temperature that will inactivate the microor-ganisms of concern. Typically, this option is easier to control and tomonitor than the previous two. In addition, the cooker temperature andcooking time can be monitored continually, which gives greater confi-dence that every item has been adequately process should be capable of operating within the bounds set by thecritical limit.

8 The parameters for the fryer minimum fryer-oil tempera-ture, maximum patty thickness and minimum cook time become thecritical Limits for the CCP. The Critical Limits should not be confused withthe operating parameters of the Operating LimitsOverhead 9If monitoring shows a trend toward lack of control at a CCP, operatorsshould take action to bring the CCP under control before the Critical limitis exceeded. The point where operators take such an action is called theoperating limit. Operating Limits should not be confused with criticallimits. Operating Limits are established at a level that would be reachedbefore the Critical limit is :Operating Limits : Criteria that are more stringent than Critical limitsand that are used by an operator to reduce the risk of a No. 3 Controlling Factors that Affect Internal TemperatureHazard presence of pathogens (microbiological)CCP fryerCritical limit minimum fryer oil temperature of 350 FCritical limit maximum patty thickness of 1/4 inchCritical limit minimum cook time in the oil of one minuteChap 7 - Principle 3: Establish Critical Limits77 Notes: Definition:Process Adjustment: An action taken by the firm to bring the processback within operating 10 The process should be adjusted when the operating limit is reached toavoid violating Critical Limits .

9 These actions are called process adjust-ments. A processor may use these adjustments to avoid loss of control andthe need to take corrective action. Spotting a trend toward loss of controlearly and acting on it can save product rework, or worse yet, productdestruction. Corrective action is only required when the Critical limit Limits may be selected for various reasons: For quality reasons ( , higher cooking temperatures for flavordevelopment or to control organisms that can cause spoilage). To avoid exceeding a Critical limit ( , a cooking temperature higherthan the Critical limit could be used as an alarm point to warn theoperator that the temperature is approaching the Critical limit andneeds adjusting). To account for normal variability ( , a fryer with a 5 F variabilityshould be set at least 5 F above the Critical limit to avoid violating it).

10 Figures 1 and 2 are graphical representations of several important points:1) operating Limits and process adjustments, 2) Critical Limits andcorrective actions, and 3) implications of lot size. In this example of ageneralized cooking process, an operating limit is established at 200 Fand a Critical limit at 190 F. Somewhere in the 10 F range between thesetwo points, wise processors will make a process adjustment to bring thecook temperature back above 200 F. Because an adjustment is madebefore the temperature drops below the Critical limit of 190 F, no HACCP record is required. However, if an adjustment is not taken until after thetemperature drops below the Critical limit, as shown in Figures 1 and 2,appropriate corrective actions must be taken and a corrective action reportmust be placed in the HACCP records file (corrective actions and recordswill be discussed in subsequent chapters).