Degree Name

BS in Dairy Science


Dairy Science Department


Rafael Jimenez-Flores


The objective of this study was to determine the effectiveness of the selected cleaners and sanitizers in killing spore-formers by preventing, treating or reducing the effects of problem spores in the dairy export industry. The chemicals used in this experiment to test against the spore-forming bacteria were Chlorine (Kem-Tek chlorinating liquid), Mandate Plus (Ecolab Clean-in-Place acid sanitizer), HD Acid PL-10 (Ecolab acid detergent for pipeline and bulk tank equipment), and Principal (Ecolab chlorinated mechanical and CIP cleaner for protein soils). The Bacillus licheniformis concentrated solution was provided by the Dairy Products Technology Center at California Polytechnic State University. Data on the effectiveness of selected cleaners and sanitizers were derived from 1:1 concentrations and 10-1 solutions that were isolated and put onto the 3M Petrifilm for observation and records. A series of dilutions were made of the sanitizers and cleaners from 1:1 to 1:10,000, but the 1:1 and 10-1 were selected to test the optimum effectiveness of each chemical. A One-way ANOVA (Analysis of Variance) was used to analyze the results, and test for differences in the 3M Petrifilm counts of 1:1 Chlorine, 10-1 Chlorine, 1:1 Mandate Plus, 10-1 Mandate Plus, 1:1 HD Acid PL-10, 10-1 HD Acid PL-10, 1:1 Principal and 10-1 Principal; statistically significance difference was set at P< .05. There was no statically significant difference between all samples. The effectiveness of Chlorine, Mandate Plus, HD Acid PL-10 and Principal at 1:1 10-1 and 10-2 was, although significant, inconclusive due to there being to many microorganisms to count. The effectiveness of the four selected chemicals at 10-1, with further dilutions of 10-1 and 10-2, contained positive results with the Bacillus licheniformis, indicating which of the four chemicals was the most effective against a spore-forming bacteria. After an incubation period, the 3M Petrifilms showed results of chlorine 10-1 having no visible growth on either dilutions of 10-1 or 10-2, denoting that Chlorine (sodium hypochlorite 10.0% and inert ingredients 90.0%) was the most effective of the four chemicals and sanitizers selected. There was only one chemical, which made had no significant difference in either the 1:1, 10-1 and 10-2, or 10-1, with further dilutions of 10-1 and 10-2. In conclusion, the addition of chlorine (sodium hypochlorite) reduces or eliminates the growth of psychrotrophic bacteria (spore-formers).