The effect of a novel low temperature-short time (LTST) process to extend the shelf-life of fluid milk

Phillip R Myer; Kyle R Parker; Andrew T Kanach; Tengliang Zhu; Mark T Morgan; Bruce M Applegate

doi:10.1186/s40064-016-2250-1

The effect of a novel low temperature-short time (LTST) process to extend the shelf-life of fluid milk

Springerplus. 2016 May 31;5(1):660. doi: 10.1186/s40064-016-2250-1. eCollection 2016.

Authors

Phillip R Myer¹, Kyle R Parker², Andrew T Kanach², Tengliang Zhu³, Mark T Morgan⁴, Bruce M Applegate⁵

Affiliations

¹ Department of Animal Science, University of Tennessee, Knoxville, TN 37996 USA.
² Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054 USA.
³ Department of Food Science, Purdue University, West Lafayette, IN 47907-2009 USA.
⁴ Food Science and Technology Department, University of Tennessee, Knoxville, TN 37996 USA.
⁵ Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054 USA ; Department of Food Science, Purdue University, West Lafayette, IN 47907-2009 USA.

Abstract

Pasteurization has long been the standard method to extend the shelf-life of dairy products, as well as a means to reduce microbial load and the risk of food-borne pathogens. However, the process has limitations, which include cost effectiveness, high energy input, and reduction of product quality/organoleptic characteristics. In an effort to reduce these limitations and extend shelf-life, this study examined a novel low temperature, short time (LTST) method in which dispersed milk in the form of droplets was treated with low heat/pressure variation over a short treatment time, in conjunction with pasteurization. Lactobacillus fermentum and Pseudomonas fluorescens Migula were exposed to conventional pasteurization treatments with and without LTST. Using these organisms, the LTST addition was able to reduce microbial load below detection limits; 1.0 × 10(1) cfu/mL, from approximately 1.2 × 10(8) and 1.0 × 10(7) cfu/mL for L. fermentum and P. fluorescens Migula, respectively. In addition, the shelf-life of the treated, raw, and uninoculated product was prolonged from 14 to 35 days, compared with standard pasteurization, to as long as 63 days with the LTST amendment. Sensory analysis of samples also demonstrated equal or greater preference for LTST + pasteurization treated milk when compared to pasteurization alone (α = 0.05). Conventional pasteurization was effective at reducing the above mentioned microorganisms by as much as 5.0 log10 cfu/mL. However, LTST was able to achieve 7.0-8.0 log10 cfu/mL reduction of the same microorganisms. In addition, BActerial Rapid Detection using Optical scattering Technology detected and identified microorganisms isolated both pre- and post-treatment, of which the only organisms surviving LTST were Bacillus spp. Increased lethality, improved shelf-life, and equal or better organoleptic characteristics without increased energy consumption demonstrate the effectiveness of the incorporation of LTST. The improved shelf-life may potentially have major impacts in the dairy industry in terms of shipping and overall sustainability.

Keywords: BARDOT; LTST; Low temperature; MST; Pasteurization.