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Subjects:
Food Science & Technology
Listeria monocytogenes is a major public health concern in milk and ready-to-eat dairy products. To meet consumer demand for fresher, minimally processed foods with high nutritional and sensory quality, several non-thermal technologies are being explored as alternatives to conventional heat treatments. This systematic review (2020–2025), following PRISMA guidelines, examines recent applications of selected non-thermal technologies to control Listeria in milk and dairy matrices. Peer-reviewed studies available in full-text, in English or Spanish, focusing on applications at laboratory or pilot plant scales, with milk or dairy produced onsite or purchased, containing Listeria sp., were included. Studies with applications to plant-based or non-dairy products or those not inoculated with Listeria, were excluded. Conference abstracts, corrections, editorials, letters, news, and scientific opinions were excluded as well. The databases searched were Web of Science, Scopus, and ProQuest, which were last consulted in April 2025. Given the naturality of the review, the risk of bias was assessed through independent screening by two of the researchers, focusing on clear objectives, analytical validity, statistical analysis, and methodology. The results are presented in tabulated format. Of the 157 records identified, 22 were included in this review. Seven of the records reported hurdle technologies, while fifteen reported single technology applications, with high-pressure processing being the most frequent. Limitations observed are primarily the use of unreported strains, a lack of information regarding the initial load of inoculum, and expected log reductions. The equipment used is mostly at the laboratory scale, except for HPP. Non-thermal technologies present a promising option for the control of Listeria in dairy products. The basic principles of GMP, HACCP, and cold-chain control in dairy processing are of special importance in safety assurance. This research was funded by Vicerrectoría de Investigación, Universidad de Costa Rica, grant number 735-C3-460.
- Listeria
- hurdle technologies
- non-thermal technologies
- dairy
Milk and dairy derivatives may be responsible for a wide variety of foodborne outbreaks due to their favorable physicochemical and nutritional features, which facilitate pathogen growth [1]. During the last decade, several listeriosis outbreaks have been associated with the consumption of contaminated dairy products, particularly cheese and ready-to-eat foods [2]. Listeria monocytogenes represents a significant public health concern in this food group, given its survival capacity in a broad range of temperatures and environmental conditions, including refrigerated storage, due to its psychrophilic nature, and a wide pH range between 4.6 and 9.5 [1][3][4].
Milk and dairy products represent one of the most important sources of transmission of L. monocytogenes to humans [5], driven in part by the high nutritional value of these products, characterized by the carbohydrates, fatty acids, and high-quality protein contents, as well as important micronutrients including vitamins, minerals, and trace elements [6]. L. monocytogenes control measures in dairy foods and dairy processing environments require permanent and diligent vigilance, monitoring, and corrective action [2].
L. monocytogenes is a facultative anaerobic, Gram-positive bacterium with a high case-fatality rate of up to 30% among foodborne pathogens. It is especially dangerous for pregnant women, neonates, the elderly, and immunocompromised individuals and is notorious for contaminating ready-to-eat (RTE) dairy products due to its persistence in processing environments and resistance to adverse conditions [3][5]. This pathogenic bacterium was identified as the etiologic agent in nearly all recent outbreaks in North America attributed to pasteurized dairy products [7]. In Europe, it is considered the most severe foodborne disease with the highest case fatality and hospitalization rates [3]. Listeriosis is manifested as gastroenteritis in immunocompromised people, as bacteremia and central nervous system infection in immunocompromised patients and elderly populations, and as placental and fetal infection in pregnant women [3]. Therefore, the establishment of preventive and control measures to avoid its presence in milk and RTE dairy products is of relevance.
L. monocytogenes contamination may occur due to cross-contamination during processing, even after pasteurization [4]. Proper and validated cleaning and sanitation protocols for food contact surfaces and non-food contact surfaces aligned with a microbial environmental monitoring program are, therefore, essential tools for reducing contamination risks [8]. The literature reports an association between hypervirulent L. monocytogenes clones and dairy products manufactured from raw milk [3]. Moreover, milk and dairy processing facilities often show organic residues and wet conditions that facilitate Listeria survival and growth. External factors may also contribute to the introduction of Listeria into processing environments, such as contaminated raw materials, wild and farm animals that may be asymptomatic carriers of L. monocytogenes, and rodents and insects, all of which are well-identified carriers and vehicles of transmission of this pathogen. Fecal shedding of Listeria by dairy cows represents a common route of entry of Listeria into dairy processing facilities, and floors, drains, conveyor belts, slicers, and tables are common locations where Listeria spp. persist in food manufacturing environments. Furthermore, Listeria may be easily spread throughout the processing environment through inappropriate personnel movements and practices, contaminated personal protective equipment, and inadequate processing workflows [8].
Conventional methods such as thermal treatments are commonly used listericidal processing approaches in dairy products; however, pasteurization and sterilization may have detrimental effects on the sensorial and nutritional quality of foods, such as heat-induced protein denaturalization, which decreases nutritional value and increases the level of undesirable aroma compounds [9][10]. As a consequence, there is growing interest in developing non-thermal processing alternatives, such as high-pressure homogenization, high-pressure carbon dioxide, high-pressure processing (HPP), pulsed electric fields (PEFs), high-intensity ultrasound, and cold plasma, for the inactivation of pathogenic bacteria and the shelf life extension of dairy foods [9][10]. Emerging non-thermal technologies are promising approaches as pathogen control hurdles, with better retention of nutrients and the fresh-like characteristics of milk components [11].
High-pressure processing is the application of pressure between 400 and 600 MPa, leading to microbiological inactivation due to cell injury and protein denaturation [12]. Pulsed electric fields, on the other hand, are the application of a high voltage (20–50 kV/cm) with short pulses at a pulse-defined frequency, which will increase the temperature through liquid foods, causing the electrical breakdown of cell membranes [11]. UV-C at a wavelength of 253.7 nm prevents the growth of bacteria, viruses, molds, and other microorganisms by introducing lethal mutations in the genomes of these microorganisms; its germicidal effect directly relates to the radiation dose and exposure time [10]. Cold plasma is based on exposing foods to plasma (the fourth state of matter) at low temperature obtained by transforming gas into ionized gas containing atoms, ions, and electrons, by providing sufficient energy. The effectiveness of cold plasma is based on the production of UV radiation, reactive oxygen species, and reactive nitrogen species; its efficacy inactivating microorganisms is highly dependent on the conductivity and viscosity of the liquid food, as well as the electric field strength, treatment time, pulse repetition frequency, process temperature, and the design and composition of the electrodes [6]. In ohmic heating (OH), electrical energy is converted into thermal energy. When an electric current passes through a food that acts as an electrical resistor, electrons collide with other electrons, atoms, and ions, and then the electrical resistance is generated and raises the temperature of the food [13].
This systematic literature review aims to address the potential application of selected non-thermal processing technologies as novel listericidal approaches to ensure the safety of milk and dairy products. The paper discusses their applications in controlling L. monocytogenes in RTE dairy foods and provides feasible suggestions for their application as listericidal processing alternatives, outlining the potential directions for the advancement and application of novel technologies in the dairy industry. Specifically, this review paper focuses on the control of Listeria monocytogenes in milk and dairy products by using high-pressure processing, pulsed electric fields, ultraviolet light, pulsed UV-light, cold atmospheric plasma, ultrasound, and ohmic heating. This literature compilation highlights alternative non-thermal processing approaches. It includes hurdles to technological applications that aim to control L. monocytogenes in milk and other ready-to-eat dairy products (L. monocytogenes can support the growth of this pathogen of public health concern), which is a critical focus and food safety challenge. A further aim of this work is to clarify the available processing technologies applicable to milk and dairy food that may be implemented by the dairy industry to mitigate Listeria cross-contamination risks after milk pasteurization.
This entry is adapted from the peer-reviewed paper 10.3390/encyclopedia5030143
References
- Kahraman, H.A.; Rugji, J.; Bektaş, T.; Erol, Z.; Tutun, H.; Keyvan, E. Inactivation of Listeria monocytogenes in Ready-to-Consume Liquid Infant Milk Treated with Ohmic Heating. Acta Sci. Technol. 2024, 46, e69714.
- Melo, J.; Andrew, P.W.; Faleiro, M.L. Listeria monocytogenes in Cheese and the Dairy Environment Remains a Food Safety Challenge: The Role of Stress Responses. Food Res. Int. 2015, 67, 75–90.
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- Everhart, E.; Carson, S.; Atkinson, K.; D’Amico, D.J. Commercial Bacteriophage Preparations for the Control of Listeria monocytogenes and Shiga Toxin-Producing Escherichia coli in Raw and Pasteurized Milk. Food Microbiol. 2025, 125, 104652.
- Nieto-Flores, K.; Sabillón, L.; Stratton, J.; Bianchini, A. Determination of an Effective Sanitizing Procedure for Listeria innocua in Personal Protective Equipment Used in Dairy Facilities. J. Food Prot. 2025, 88, 100455.
- Abbas, H.M.; Altamim, E.A.; Salama, M.; Fouad, M.T.; Zahran, H.A. Cold Plasma Technology: A Sustainable Approach to Milk Preservation by Reducing Pathogens and Enhancing Oxidative Stability. Sustainability 2024, 16, 8754.
- Atik, A.; Gumus, T. The Effect of Different Doses of UV-C Treatment on Microbiological Quality of Bovine Milk. LWT 2021, 136, 110322.
- Araújo, A.; Barbosa, C.; Alves, M.R.; Romão, A.; Fernandes, P. Implications of Pulsed Electric Field Pre-Treatment on Goat Milk Pasteurization. Foods 2023, 12, 3913.
- Zagorska, J.; Galoburda, R.; Raita, S.; Liepa, M. Inactivation and Recovery of Bacterial Strains, Individually and Mixed, in Milk after High Pressure Processing. Int. Dairy J. 2021, 123, 105147.
- Cho, E.-R.; Kang, D.-H. Development and Investigation of Ultrasound-Assisted Pulsed Ohmic Heating for Inactivation of Foodborne Pathogens in Milk with Different Fat Content. Food Res. Int. 2024, 179, 113978.
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