Related Experiment Video

Updated: Jun 19, 2026

Metagenomic Analysis of Silage
08:43

Metagenomic Analysis of Silage

Published on: January 13, 2017

Fat content increases the lethality of ultra-high-pressure homogenization on Listeria monocytogenes in milk

A X Roig-Sagués1, R M Velázquez, P Montealegre-Agramont

  • 1NUTEC, Dep. de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain. ArturXavier.Roig@uab.cat

Journal of Dairy Science
|October 21, 2009
PubMed

Insights

Ultra-high-pressure homogenization (UHPH) effectively reduced Listeria monocytogenes in high-fat milk. However, lower fat content and milder pressures allowed bacterial recovery during cold storage.

Area of Science:

  • Food Microbiology
  • Food Processing Technology
  • Food Safety

Background:

  • Listeria monocytogenes is a significant foodborne pathogen.
  • Milk fat content can influence the efficacy of microbial inactivation treatments.
  • Ultra-high-pressure homogenization (UHPH) is a non-thermal processing technology used for microbial decontamination.

Purpose of the Study:

  • To evaluate the impact of milk fat content on Listeria monocytogenes inactivation by UHPH.
  • To determine the effectiveness of UHPH at different pressure levels (200-400 MPa) against L. monocytogenes.
  • To assess the recovery and growth of L. monocytogenes in milk post-UHPH treatment during cold storage.

Main Methods:

  • Milk samples with varying fat content (0.3% to 15%) were inoculated with Listeria monocytogenes.
  • Samples underwent a single cycle of UHPH treatment at 200, 300, or 400 MPa.
  • Microbiological analysis was conducted immediately after treatment and after 15 days of refrigerated storage (4°C).

Main Results:

  • Higher milk fat content (10-15%) and higher pressure (400 MPa) resulted in maximum L. monocytogenes inactivation.
  • Complete inactivation was not achieved in skimmed or low-fat (0.3-3.6%) milk, with bacteria recovering during storage.
  • L. monocytogenes recovered to initial levels in high-fat milk (10-15%) only after treatment at 200 MPa, not at 300 or 400 MPa.

Conclusions:

  • Milk fat content significantly influences the lethality of UHPH against Listeria monocytogenes, with higher fat enhancing inactivation.
  • While UHPH can reduce bacterial load, complete elimination and prevention of recovery are dependent on both pressure and fat content.
  • The findings highlight the importance of optimizing UHPH parameters in conjunction with milk composition for effective microbial control.

More Related Videos

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food08:38

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

Published on: May 6, 2013

Evaluation of the Efficacy of Organic Peroxyacids for Eradicating Dairy Biofilms Using an Approach Combining Static and Dynamic Methods11:47

Evaluation of the Efficacy of Organic Peroxyacids for Eradicating Dairy Biofilms Using an Approach Combining Static and Dynamic Methods

Published on: December 9, 2022

Related Concept Videos

Pasteurization and Food Preservation01:28

Pasteurization and Food Preservation

Pasteurization is a widely employed thermal processing technique designed to enhance the safety and shelf life of perishable food and beverages. By subjecting products to specific high temperatures for controlled durations, this method effectively inactivates pathogenic microorganisms and spoilage enzymes without significantly compromising sensory qualities. The technique has been pivotal in food safety management, especially for consumables susceptible to microbial contamination such as milk,...
Physical Methods for Controlling Microbial Growth: Temperature01:23

Physical Methods for Controlling Microbial Growth: Temperature

Heat is a widely used method to control microbial growth by targeting and denaturing cellular proteins, thereby killing or inactivating microbes. This method's effectiveness is quantified using parameters such as the thermal death point (TDP), thermal death time (TDT), and decimal reduction time (D value). TDP represents the lowest temperature at which all microorganisms in a liquid suspension are eliminated within 10 minutes, whereas TDT is the time necessary to achieve sterilization at a...
Microbes in Food Production01:29

Microbes in Food Production

Microbial fermentation is central to food biotechnology, enhancing flavor, texture, preservation, and stability. Fermentative microorganisms metabolize carbohydrates into organic acids, alcohols, and other metabolites that inhibit spoilage organisms and improve digestibility while contributing distinctive sensory qualities.In baking, amylases naturally present in flour hydrolyze starch into monosaccharides such as glucose, which Saccharomyces cerevisiae ferments anaerobically. Through...
Tissue Homogenization and Cell Lysis01:32

Tissue Homogenization and Cell Lysis

Tissue homogenization involves disintegrating tissue architecture and lysing cells, and is an early step in isolating and analyzing cellular components. The method used for homogenization depends on the sample type, the amount of sample available, the analyte to be obtained, and the sensitivity of the method. These methods are broadly classified as mechanical and non-mechanical methods.
Mechanical methods of tissue homogenization
These methods rely on applying external physical force to disrupt...
Methods of Controlling Food Spoilage01:26

Methods of Controlling Food Spoilage

Food spoilage is caused by microbial growth or by chemical and physical changes, all of which affect the taste, texture, and safety of food.Temperature-Based PreservationRefrigeration at 0–4 °C slows microbial growth and enzyme activity, making it ideal for short-term storage. However, certain spoilage organisms—such as psychrotrophs like Listeria monocytogenes—can still proliferate at these temperatures. Freezing below -18 °C further slows biological processes by forming ice crystals, which...
Microbial Spoilage of Food01:23

Microbial Spoilage of Food

Microbial food spoilage refers to the degradation of food quality resulting from the metabolic activity of microorganisms such as bacteria, yeasts, and molds. These microbes proliferate on various food substrates depending on factors such as moisture content, nutrient availability, and storage conditions, leading to undesirable sensory and structural changes.Bacteria are primary agents of spoilage in high-moisture, nutrient-dense foods like meat, milk, and vegetables. Microbial spoilage occurs...