Food Protection Trends - March 2010 - 162

TABLE 2. Microorganisms found in cannery cooling water Source of cooling water and/or type of cooling system Can cooling water and/or post process can handling equipment Well water Sanitizers used References Microorganisms Flavobacterium, Bacillus and Corynebacterium Streptococcus, Staphylococcus aureus, Bacillus spores and clostridial spores Klebsiella sp., Pseudomonas aeruginosa and clostridial spores Coliforms, enterococci and putrefactive anaerobic spores Chlorine (2) Chlorine (20) Surface water Chlorine (20) Cooling canals or tanks for continuous and hydrostatic retorts Chlorine or iodine Residual chlorine up to 8 ppm (mg/l) Residual chlorine up to 5 ppm (7, 11) Mesophilic, thermophilic and anaerobic spores Cooling canals for hydrostatic retorts Chlorine or iodine. Residual chlorine up to 3 ppm Residual iodine up to 4 ppm Free available chlorine 0.02 – 0.75 ppm, pH = 7.2 (19) Mesophilic anaerobic sporeformers – C. perfringens, C. durum, C. butyricum and C. beijerinkii Cannery cooling water (29) Can cooling water studies were conducted in 1976 by the former National Canners Association (currently the Grocery Manufacturers Association) (unpublished data). The cooling systems in 17 canneries were surveyed and 203 cooling water samples were analyzed. The aerobic plate counts (APC) for 64% of the samples were in the range of less than 1 to 100 CFU/ ml. Spores of aerobic mesophilic bacteria were present in 20% of the samples, and the maximum count did not exceed 20 CFU/ml. Spores of anaerobic mesophilic bacteria were recovered, but in low numbers and from only 5% of the samples. In general, anaerobic sporeformers showed a gradual increase when the APC population counts exceeded 100 CFU/ml (17). OVERALL MICROBIOLOGy OF COOLING AND WELL WATERS Table 2 indicates that a variety of microorganisms may be present in cannery cooling water, including spores of mesophilic anaerobes and aerobes. These organisms are usually present in low numbers, and their presence is dependent on the source of the cooling water, the type of cooling water systems used and the amount of effective germicide present. However, the APC populations in some instances were high (> 2.1 × 104 CFU/ml) and for this reason some of the microbial examinations were extended to include indicator organisms and bacteria associated with food poisoning (7). Most of the microorganisms isolated from the sanitized cooling water were obligate anaerobic mesophilic sporeforming rods that produced volatile fatty acids and displayed fermentation patterns typical for the genus Clostridium (19, 29). Clostridium perfringens, which is both proteolytic and saccharolytic, and saccharolytic C. durum, C. butyricum and C. beijerinckii were isolated (29). Put et al. (20) found Streptococcus, Staphylococcus aureus, Bacillus spores and clostridial spores in the chlorinated well water. The canneries using chlorinated surface waters contained higher numbers as well as a greater variety, of microorganisms including Klebsiella sp., Pseudomonas aeruginosa and clostridial spores (20). Graves et al. (7) noted a relationship between APC and the inci- 162 FOOD PROTECTION TRENDS | MARCH 2010

Food Protection Trends - March 2010

Table of Contents for the Digital Edition of Food Protection Trends - March 2010