Guide to Inspections of Low Acid Canned Food 10
Manufacturers - 1
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Without a properly established process, process control at the processor is useless. Establishing processes requires among other things; 1) considerable knowledge about product characteristics and the effect of each processor's equipment and procedures on those characteristics of importance to heat penetration; 2) experience in conducting heat penetration, temperature distribution, thermal death time studies and other scientific methods; and 3) the ability to determine through evaluation of data generated by these studies and tests, that sufficient testing has been accomplished to identify all possible factors that could affect the heating characteristics of the product and the safety of the final product.
The written documentation delineating the scheduled process should include initial temperature, process time, process temperature and least sterilizing value, and also address such items as formulation, if critical, and maximum or minimum values of other critical factors.
A processing authority is also responsible for establishing the adequacy of temperature distribution in retorts, including the establishment of venting schedules for retorts using pure steam (unless venting schedules referenced in 21CFR Part 113.40(a)(12)(i)or(ii) are used, provided that the retorts are equipped according to specifications in Part 113), or retort come-up procedures for retorts using water immersion, water sprays, or steam air mixtures.
21 CFR 113.40(a)(12)(iii) also permits other installations and procedures, provided there is evidence, in the form of heat distribution data kept on file, demonstrating that the equipment and procedures accomplish adequate venting of air.
Occasionally process authorities develop venting procedures that do not specify minimum vent time. Such a vent procedure would be specific for a particular installation; would be based on reaching a minimum retort temperature; and would be developed by performing heat distribution studies involving the shortest possible time to achieve a minimum temperature.
Automating the vent procedure and/or avoiding the need to record the 'time vent closed', are just two reasons why a processing authority might consider developing a vent procedure of the type described. For example, a process authority may determine for a specific installation that the shortest possible time to reach 2250 F is 4 minutes. If the studies show adequate heat distribution is achieved when 2250 F is attained, time vent closed would not be a necessary component of the recommended venting procedure and would not need to be recorded. In cases where the venting, and/or retort installation and procedures are not as specified in 21 CFR 113, contact CFSAN (HFS-617) to determine if an evaluation is necessary.
It is often necessary for a processing authority to recognize the inadequacies or inexperience of a processor in order to provide the processor with sufficient information to ensure understanding of what factors are critical; how to measure them; and how to control them. For example, maximum fill drained weight (of solids after brining) may be listed as a critical control factor. A processor may control fill weight by conducting tests before brine is placed into the can, without realizing that these tests are not measuring the identified critical factor. Another example is sauce viscosity which often has to be measured within the correct temperature range using a specific instrument as studied during heat penetration testing. Failure to properly convey critical factor methodology could result in the failure to deliver the scheduled process. In some cases, it may suffice to state that a particular factor is not critical (i.e., headspace, if cans without headspace were used in the tests).
A processing authority is responsible for the evaluation of processing deviations (21 CFR 113.89); to determine whether a specific lot is, or is not, a potential danger to health. The decision is usually based only on the review of processing and production records, which are presumed to be accurate. The processing authority may assume that other factors were controlled, and that equipment, including measuring devices, were properly adjusted (some processing authorities make a statement in their evaluation letters to the effect: provided all other processing parameters were in conformance...). In most cases, these assumptions are valid, but records should be carefully reviewed for any indications of discrepancies. The processor should submit the fill weight records, or records documenting control of other critical factors when there has only been a temperature drop. If the processing authority cannot verify that all other critical factors were controlled, a complete and accurate evaluation cannot be made.
If the deviations submitted to the processing authority were discovered by an FDA Investigator, the Investigator should stress to the firm that the FDA 483 should be submitted to the processing authority with the other records covering the process deviations. For example, the Investigator may have observed higher fill weights than the records indicate or that the firm determines fill weight improperly; critical information when evaluating a deviant process.