Fluid Milk Spoilage by Psychrotolerant Spores and Shelf-Life Improvement

Cornell University researchers created a new predictive model that examines spore-forming bacteria and their impact on pasteurized milk shelf life, published in the August issue of the Journal of Dairy Science entitled “Psychrotolerant spore-former growth characterization for the development of a dairy spoilage predictive model”. The goal of the research was to create a mathematical model to increase the product shelf life and have a more meaningful and accurate way to estimate the shelf life. This can reduce food waste and reduce food spoilage, by a better understanding of the parameters driving spoilage.

The researchers characterized the ability to germinate and grow 14 psychrotolerant spore-formers. The organisms used representing the most common Bacillales subtypes (e.g. Bacillus, Lysinibacillus, Paenibacillus, Psychrobacillus, Viridibacillus) from raw and pasteurized milk at 6°C. Growth curves were generated by counting total bacterial count and spore count every day for 30 days at 6°C. The obtained data d can serve as the foundation for the development of better tools to predict the shelf life of fluid milk.

The researchers developed a predictive model to investigate the growth of psychrotolerant spore-forming bacteria. Such a model allows the identification of parameters that most effectively can increase the shelf life of fluid milk.

They used a Monte Carlo simulation model to predict the spoilage patterns. The model assumed that the spoilage level for fluid milk is >20,000 cfu/mL. Monte Carlo model predicted that 66% of ½ gallons milk pasteurized at high temperature, for short time would reach the critical level of 20,000 cfu/mL after 21 days of storage at 6°C, in agreement with current spoilage rate.

The parameter that influenced most of the shelf life was the maximum growth rate of psychrotolerant spore-formers. The research showed that different psychrotolerant spore-formers have different abilities to germinate and grow in fluid milk.   Better characterization of the ability to germinate and the growth rates of the diverse of psychrotolerant spore-formers will have the best impact on improving the model.

The second parameter that influences the model is the initial concentration of psychrotolerant spore-formers in the bulk raw tanks.  The model shows that microfiltration can reduce the initial numbers of psychrotolerant spore-formers by 2.2 logs, the shelf life can be extended by 4 days.

The research data indicates that if the numbers of spore-forming bacteria are reduced and if their outgrowth can be controlled, the shelf life of milk can be improved from 2 weeks to a month.  The created model shows that if the milk is kept refrigerated at 40 C, instead of 60 C only 9% of the milk will spoil in 21 days as compared with 66% at the currently used temperature.

To produce high-quality milk with extended shelf life, it is essential to control psychrotolerant spore-formers. The study identifies growth parameters that are required to consistently predict the shelf life of fluid milk due to psychrotolerant spore-formers. Processing decisions and storage of the milk through the supply chain can reduce spoilage due to spore-formers.

The authors emphasize that the model developed provides a new tool for the dairy industry to predict the shelf life of pasteurized milk and extend it. This could allow manufacturers to provide a more meaningful “sell-by-date”. The model demonstrates the effectiveness of predictive modeling for the dairy industry and allows a “what if” analysis to estimate the outcome of different processing procedures.

2 comments

2 responses to “Fluid Milk Spoilage by Psychrotolerant Spores and Shelf-Life Improvement”

  1. eluxury louis vuitton

    C.G INC supply 100% authentic Louis Vuitton outlet here offers cheap Louis Vuitton,authentic Louis Vuitton,Louis Vuitton handbags,Louis Vuitton bags,Louis Vuitton purses online with free shipping.Welcome to Louis Vuitton official website and enjoy shop…

  2. canadian prices for sildenafil

    BioExpert Fluid Milk Spoilage by Psychrotolerant Spores and Shelf-Life Improvement ⋆ BioExpert

Leave a Reply