Publication underlines HPP & Phageguard L (PGL) synergy

Non-thermal hurdle approach to control Listeria in foods by using Phageguard L (PGL) and high pressure processing (HPP) treatment

Komora et al. (2018) shows an interesting, sequential hurdle approach combining PGL and high pressure processing, to enhance control of Listeria in foods. A multi hurdle approach is the combined use of more than one preservation techniques to control or eliminate pathogens in food and make end-products more shelf stable. This strategy can be applied to a wide category of food products – dairy, fresh meat, fruits and vegetables and minimally processed foods. The authors evaluated the effect of different pressures on phage stability when applied on different food matrices. Milder pressures of 200-300 MPa for 5 mins at 10 ºC was found optimal for phage activity on foods such as fermented sausage “Alheria”, cheese “Serra da Estrela” and UHT whole milk. In addition, at milder pressure conditions, the phage inactivation rate during the HPP process was independent of initial phage level, after which phages remained stable during the shelf life of 28 days for milk and up to 60 days for sausage and cheese. Although HPP partly inactivates bacteriophages, Komora et al. determined that food components such as reducing sugars, dextrins, casein and tween 80 can help to reduce phage inactivation when subjected to hydrostatic pressure treatment. Interestingly, Komora et al. (2019) also showed that UHT whole milk when pressurized and phage treated can result in complete inactivation of L. monocytogenes during the whole refrigerated shelf life. This result illustrates that the combination of HPP and Phageguard L can be a powerful combination to significantly reduce L. monocytogenes in food production processes making a significant impact on food safety.