Process-Related Hazard and Control #6 Hazard:
Pathogen survival through cooking

Food and Drug Administration

Pathogen survival through the cook step
(excluding blue crab, red crab, and dungeness crab).

Hazard Statement: Pathogen survival through the cook step is a food safety hazard for cooked, ready to eat products. The cooking process should be sufficiently lethal to inactivate (kill) the vegetative cells of such pathogens as L. monocytogenes, Vibrio spp., and Salmonella spp. These pathogens are commonly present on the raw product. They must be eliminated during the cook step so that they are not carried over into the finished product, which may not be cooked by the consumer. Furthermore, they must be eliminated so that they are not introduced into those areas of the processing environment in which the cooked product is processed.

A minimum acceptable process should be scientifically established to assure that the cook step eliminates microorganisms of public health significance. Expert knowledge of thermal process calculations is required to establish such a process. Often this is done by an outside expert, referred to as a "process authority". Procedures used to establish the minimum thermal process must be generally recognized and accepted. In some cases, thermal death time, heat penetration, and inoculated pack studies will be required to establish the minimum process. In other instances, existing literature or federal, state or local regulations, which establish the minimum process, are available. Characteristics of the process and/or the product that affect the ability of the cook step to eliminate the microorganisms of public health significance should be taken into consideration in the establishment of the process. The methods to control such microorganisms should be specified by the process authority.

Processing equipment must be designed and operated so that every unit of product receives the established minimum process. A competent process authority, thoroughly familiar with the dynamics of heat transfer in processing equipment, must evaluate the design and operation of the type of equipment used by the processor. In some cases, temperature distribution studies are needed to establish the adequacy of the equipment. In other instances, existing literature is available to the processor that will establish the adequacy of the equipment.

Studies have confirmed that the minimum cooking process normally applied to blue crab (Callinectes sapidus), dungeness crab (Cancer magister), king crab (Paralithodes spp.) and golden crab (Lithodes aequispina) is exceptionally lethal to the vegetative cells of microorganisms of public health concern (e.g., L. monocytogenes). These products could not be produced without providing such a lethal process. Therefore, this guideline does not treat the cook step for these products as a critical step.

Critical Control Point: Cooking

1. Make sure that the cooking process that is being used was designed to inactivate vegetative cells of microorganisms of public health concern. The adequacy of the cooking process should be established by a process authority, except that, in the processing of hotsmoked fish, processors should use the critical limit, below, as their minimum process. The cooking process that is being used should meet any factors of the process or of the product that are identified by the process authority as critical to achieving inactivation of pathogens. At a minimum, these critical factors should include cooking time and temperature.
2. Make sure that the cooking equipment being used is properly designed and operated to deliver the cooking process established by the process authority. The engineering specifications of the equipment being used (e.g., pipe sizes, flow rates, loading pattern) should meet or exceed that of the equipment evaluated by a process authority. Processors of hotsmoked fish need not meet this provision, because product internal temperatures are specified in the critical limits.
3. Deliver the cooking process so that there is no deviation from the minimum established cooking critical factors.
4. Monitor the cooking temperature with a temperature-recording device (i.e., temperature recorder). The temperature recorder should be installed where it can be easily read and the sensor for the device should be installed to ensure that it accurately measures the coldest temperature of the cooking equipment. The temperature-recording device on cooking equipment used to prepare hot smoked fish should also be equipped with sufficient probes to monitor the internal temperature of the thickest portion of at least three of the largest fish in each load. The temperature recorder must show a continuous record of the process. Computerized storage of temperature data may be used in place of a temperature recorder chart if the use of such a system has been validated and can be shown to be equivalent to the use of a temperature recorder.
5. Check the accuracy of each temperature recorder at the beginning and end of each production day and adjust it as necessary to agree as nearly as possible to but never above a temperature- indicating device (mercury in glass thermometer or equivalent device) located on the cooking equipment. The thermometer should be installed where it can be easily read and placed to ensure that it accurately measures the coldest temperature of the cooking equipment.
6. Calibrate the thermometer at the cooking temperature against a known accurate standard thermometer. This should be done when the thermometer is installed and at least once a year after that, or more frequently, if necessary, to ensure its accuracy.
7. Monitor the length of the cooking cycle.
8. Monitor other critical factors (e.g., product size or initial temperature) for as often as necessary to achieve control for each lot of product produced. The frequency will depend on the variable being controlled, the historic variability of the variable, and the proximity of the normal values to the critical limits.

Example: ABC Fish Co. produces cooked ready to eat shrimp. ABC Fish Co. has obtained a copy of a State University Sea Grant publication concerning cook times and temperatures and initial temperatures for various sizes of shrimp in a steam tunnel like the one located in the processing plant. The publication also specifies venting times and temperatures necessary to ensure that the temperature within the steam tunnel is uniform before product is allowed to enter. ABC Fish Co. compared their steam tunnel equipment to the equipment described by the study. Then they made some minor changes to the equipment to be sure that all of the engineering specifications were equivalent. Ace monitors and records: the time the steam is turned on; the time it is turned off; the initial temperature of the product; the time that the temperature of the cooker has reached the minimum cook temperature; the time that product first enters the cooker; the belt speed each time it is adjusted; the cook length (calculated from the belt speed); and, the shrimp size once per hour for each grade being cooked. The steam tunnel temperature is continuously monitored by a temperature recorder, with its sensor placed according to the publication instructions. The accuracy of the recorder is checked and adjusted every two hours against a mercury in glass thermometer at the cook temperature. The thermometer is also located in the steam tunnel, next to the recorder thermometer. The thermometer is calibrated at the cook temperature twice per year by a contract laboratory. The steam tunnel temperature is automatically controlled by the recorder/controller, preset for 0.5ºC (1ºF) above the minimum temperature required by the publication. The belt speed is set to ensure 1/2 minute more than the minimum cook time for the size shrimp being processed. Adequate venting of the tunnel is assured by not allowing product to enter the cooker until it has reached the process temperature for the minimum time required by the publication.

Frequency

1. For making sure that the cooking process is properly established: before using a cooking process.
2. For making sure that the cooking equipment is properly designed: before using cooking equipment.
3. For proper processing: each lot or batch.
4. For monitoring the temperature: continuously during each lot or batch.
5. For checking the accuracy of the temperature recorder: at the beginning and end of each production day.
6. For calibrating the thermometer: at installation and at least annually after that.
7. For monitoring the length of the cook cycle: each lot or batch.
8. For monitoring other critical factors: as often as necessary to achieve control.

Critical Limits

No product should deviate from the minimum established for the cooking process, including such critical factors as time, temperature, product size, and initial temperature.

A continuous internal temperature of at least 63ºC (145ºF) for a minimum of 30 minutes throughout the slowest heating fish that is hotsmoked.

For coldsmoked fish to be air packaged, one of the following conditions should be met:

• The temperature in the smoking chamber does not exceed 32ºC (90ºF) during a drying and smoking period that does not exceed 20 hours;
• The temperature in the smoking chamber does not exceed 10ºC (50ºF) during a drying and smoking period that does not exceed 24 hours.
• For sablefish, the temperature in the smoking chamber does not exceed 49ºC (120ºF) during a drying and smoking period that does not exceed 6 hours.

The thermometer recorder should be adjusted to agree as nearly as possible, with but never higher than the indicating thermometer.

The indicating thermometer should agree within 1ºC (±2ºF) of the NIST-traceable thermometer.

Records

A record that describes the results of a scientific evaluation, conducted by a process authority, of the adequacy of the cooking process. Such document may consist of, but is not limited to, a letter from a process authority, articles in scientific journals, or federal, state, or local government regulations or advisories.

A record that describes the results of a scientific evaluation, conducted by a process authority, which applies to the design and operation of the type of equipment used by the processor.

Temperature recorder charts, which show cooking equipment temperature and, for salted, hotsmoked fish, at least three fish internal temperatures;

A record for each lot or batch that shows the results of the cooking process. The records should include: the size of the batch by weight; the time of day that the steam or heat is turned on (for steam or dry heat batch cooked); the time of day that the vent is closed (for steam cooked in closed vessel); the temperature at the time of closure (for steam cooked in closed vessel); the time of day that the product is placed in the water (for water batch cooked); the time of day that the cooking temperature is achieved after the product is added (for steam, water and dry heat cook [internal temperature in hotsmoked fish]); the time of day that the cook ends (for steam, water and dry heat cook); the belt speed (for continuous cook); and, as appropriate, the product size and any other factors of the process or of the product that are identified by the process authority as critical to achieving pathogen destruction;

Records of process evaluation by the process authority, where deviations from critical limits occurred;

A record of calibration for thermometers that specify the date, standard used, method used, results, and person performing the test;

A record of accuracy checks for the temperature recording devices that species the time, date, temperatures shown by both devices before adjustment, corrective action taken and person performing the accuracy check;

Corrective Action

When there has been a failure to maintain appropriate temperature, time, or other critical factors of the process or of the product, within the critical limits, the affected product should be:

• destroyed, or;
• reprocessed to eliminate the hazard, keeping full records of the processing conditions, or;
• segregated and held until an evaluation can be made to learn the effect of the deviation. The evaluation should be made by a process authority and should be in accordance with recognized procedures. Unless the evaluation shows that the product has received an adequate cook to achieve pathogen destruction, the product should be reprocessed to eliminate the hazard or the product should be destroyed.

Indicating or recording thermometers that cannot be adjusted to within the critical limits should be replaced. A thermometer that has a divided fluid column should be immediately repaired or replaced.

Any critical limit deviation should cause a timely assessment by management to: learn whether the process or HACCP plan needs to be changed to reduce the risk of recurrence of the deviation, and take appropriate followup action.