Guide to Inspections of Low Acid Canned Food 45
container cooling water must be chlorinated or otherwise sanitized as necessary in cooling canals and for recirculated water supplies. There should be a measurable residual of the sanitizer employed at the water discharge point of the container cooler.
Water from either municipal sources or wells may be used in canals. Municipal water supplies may be chlorinated by the water supplier before entering the plant system. Well water may, or may not, be chlorinated in the plant. Most local and or state governments also require testing of well water at various times to determine water quality.
The investigator must use good judgement in selecting where samples should be collected to measure cooling water sanitizers. Normally the water at the greatest distance from where the sanitizer is put into the system would be where the sanitizer would be expected to be at it lowest level. This may not however always be the case. A number of factors can influence the level of sanitizers in cooling water. Examination of the cooling water systems should help in making those determinations. The investigator should determine where and how the sanitizer is added to the system. How the firm determines sample sites, performs residual sanitizer tests and adds sanitizer to the system may be important. In some systems where sanitizers are added to hot water the sanitizer may be driven off by the heat. In other systems the amount of organic material in the water may effect the sanitizer levels in different parts of the system. It may be necessary to sample from several different locations in the cooling water system especially if a problem is suspected. After prolonged use (sometimes in excess of a day or more) the water in cooling canals and recirculated water becomes contaminated, hence the requirement for chlorination of cooling canals and recirculated water specifically mentioned in 21 CFR 113.60(b).
The regulation does not specifically mention continuous retort shells or hydrostatic legs. However, If cooling water from hydrostatic legs or cooling shells is circulated through a cooling tower and then returned to the leg or shell, it would be considered recirculated cooling water and would be covered by the regulation. If replacement water is recirculated before being added to cooling shells or hydrostatic legs, these cooling devices would be covered under the regulation. If replacement water is fresh, the regulation would not apply.
21 CFR Part 113.60(d) requires that when cans are handled on belt conveyors, the conveyors should be so constructed as to minimize contact by the belt with the double seam, i.e., cans should not be rolled on the double seam. All worn and frayed belting, can retarders, cushions, etc. should be replaced with new non-porous material. The can conveyor system should have an automatic shut-off when there is a can jam, to stop the cans from moving and prevent the conveyor from abrading the can seams. All tracks and belts that come into contact with the can seams should be thoroughly scrubbed and sanitized at intervals of sufficient frequency to avoid product contamination. Automatic equipment used in handling filled containers should be so designed and operated as to preserve the seam or seal or other container closure integrity. The can conveyor system should have an automatic shut off for can jams.
Maintaining container integrity extends beyond the process operation to the post-cooling container handling system. Studies have indicated that excessive bacterial contamination may develop on wet and soiled post-cooling equipment even if the cooling water is chlorinated or of naturally sanitary quality. Bacterial contamination can be transferred to the seam or seal areas as they pass through the handling systems. Under such conditions, post-cooling container handling systems have been the causative agents in spoilage due to recontamination.
Observe the handling of filled and retorted containers and evaluate the likelihood of damage from rough handling. Check retort crates and/or baskets and other container handling equipment (conveyors, channels, etc.) for sharp edges and/or protrusions which could damage container seams or seals and/or puncture container bodies, ends or pouches. If the containers are roughly handled after processing, the seams or seals may be damaged, or in the case of rigid metal container bodies, dented under the seam. Rough handling or denting could cause a momentary break at the seal point. Leaks caused by dents or by damaged or defective seams and seals can result in the contamination of the commercially sterile product by such toxin-producing bacteria as staphylococci and Clostridium botulinum, as well as other types of toxin producing or spoilage bacteria. Flexible and semirigid containers must be handled carefully to prevent containers from being slit, punctured or damaged.
The sanitary condition of the container handling lines, and the resultant contamination transferred to the containers, is directly related to the amount of moisture present in which the spoilage organisms are suspended and grow. Moisture is needed for transfer of bacteria to the container closure and moisture is needed for the bacteria to move through the closure into the container.
Observe that cooling and drying procedures are conducted in a manner to protect against post-