Food Science and Technology Department


First Advisor

Andreia Bianchini

Second Advisor

Jayne Stratton

Date of this Version

Fall 11-9-2021


Crespo Ramirez, R.A. (2021). Risk Based Simulations of Sporeformers Population Throughout the Dairy Production and Processing Chain: Evaluating On-Farm Interventions in Nebraska Dairy Farms. PhD diss, University of Nebraska-Lincoln. Food Science & Technology.


A DISSERTATION Presented to the Faculty of The Graduate College of the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Food Science and Technology, Under the Supervision of Professors Andreia Bianchini and Jayne E. Stratton. Lincoln, Nebraska: November, 2021

Copyright © 2021 Rhaisa Alejandra Crespo Ramirez


Sporeformer bacteria are ubiquitous in the farm environment. These bacteria produce enzymes that negatively affect the quality of dairy products representing a problem for the dairy industry. Two major issues associated with high levels of sporeformers in raw milk are shelf-life reduction of fluid milk and market limitations for milk powder. Specific attention has been given to the contamination of milk powders with sporeformers due to their ability to survive pasteurization and milk powder processing conditions. Hence, the control of sporeformers is crucial to benefit the whole dairy industry. Researchers have suggested that certain management practices could decrease sporeformers in raw milk, improving the quality and price of dairy products. To address these issues, this research focuses on identifying common practices used by Nebraska’s dairy farmers to determine areas where changes could be applied to reduce sporeformers. Changes were implemented at three different farms in Nebraska and simulations were created to predict the efficacy of such changes in reducing sporeformers in milk powder. The identification of common practices suggests that Nebraska’s dairy farms have acceptable management practices, and changes favored by farmers included changes in teat sanitizer, clean-in-place chemicals, and detergents used for cleaning and sanitizing towels. The implementations of these practices, and a change in bedding protocol, were applied at three different farms. Among seven evaluated interventions, the clean-in-place, bedding, and towel sanitizing protocols effectively reduced the concentration of sporeformers in raw fluid milk and predicted for milk powder. From three teat sanitizers tested, two resulted in conflicting results, while one showed promising results in a single simulation. In summary, contamination of sporeformers increases from the farm to the final product, and interventions targeted at the farm can aid in the reduction of sporeformers in the final product. In addition, the developed risk-based model provides a framework for the milk powder production chain to evaluate intervention strategies applied throughout the continuum from farm to final product.

Advisor: Andréia Bianchini