Review: elimination of bacteriophages in whey and whey products

Abstract

As the cheese market faces strong international competition, the optimization of production processes becomes more important for the economic success of dairy companies. In dairy productions, whey from former cheese batches is frequently re-used to increase the yield, to improve the texture and to increase the nutrient value of the final product. Recycling of whey cream and particulated whey proteins is also routinely performed. Most bacteriophages, however, survive pasteurization and may re-enter the cheese manufacturing process. There is a risk that phages multiply to high numbers during the production. Contamination of whey samples with bacteriophages may cause problems in cheese factories because whey separation often leads to aerosol-borne phages and thus contamination of the factory environment. Furthermore, whey cream or whey proteins used for recycling into cheese matrices may contain thermo-resistant phages. Drained cheese whey can be contaminated with phages as high as 109 phages mL-1. When whey batches are concentrated, phage titers can increase significantly by a factor of 10 hindering a complete elimination of phages. To eliminate the risk of fermentation failure during recycling of whey, whey treatments assuring an efficient reduction of phages are indispensable. This review focuses on inactivation of phages in whey by thermal treatment, ultraviolet (UV) light irradiation, and membrane filtration. Inactivation by heat is the most common procedure. However, application of heat for inactivation of thermo-resistant phages in whey is restricted due to negative effects on the functional properties of native whey proteins. Therefore an alternative strategy applying combined treatments should be favored – rather than heating the dairy product at extreme temperature/time combinations. By using membrane filtration or UV treatment in combination with thermal treatment, phage numbers in whey can be reduced sufficiently to prevent subsequent phage accumulations.

Bacteriophages on dairy foods

“…With regard to the levels of contamination in air, Atamer et al . () reported phage counts close to 10 8 PFU per m 3 . Liquid splashes and air displacement around vats and other contaminated surfaces generate aerosols, which remain in air for long periods and are recognized as a major route of phage dissemination in dairies (Verreault et al .…”

“…Phages native from raw milk were still infective after diverse heat treatments (Atamer et al . ; Capra et al . ; Tayyarcan et al .…”

Application of a membrane technology to remove bacteriophages from whey

“…Generally, phage particle dimensions are similar to whey protein sizes (<20 nm), while the length of phage tail ranges from 120 nm to 450 nm and the head varies from approximately 50 to 75 nm (Atamer et al, 2013). Hence, the aim of this study was to characterize membranes that retain bacteriophages and allow whey proteins to permeate.…”

“…Whey can be transformed into diverse native whey protein supplements or can be directly used as additives in various fermented products to achieve a significant increase in product yield or to improve product texture and nutritional value (Atamer, Samtlebe, Neve, Heller, & Hinrichs, 2013;Atra, Vatai, BekassyMolnar, & Balint, 2005;Schenkel, Samudrala, & Hinrichs, 2013;Toro-Sierra, Tolkach, & Kulozik, 2013;de Wit, 1998). Whey can be incorporated in cheese in its native state by standardizing the cheese milk prior manufacturing, or in its denatured form as microparticulated whey protein or heat treated whey cream (Brown & Ernstrom, 1982;Hinrichs, 2001;Lawrence, Creamer, & Gilles, 1987;Lo & Bastian, 1998;Schenkel, Samudrala, & Hinrichs, 2011).…”

Optimization of Two-Stage and Single-Stage Anaerobic Reactors Treating Cheese Whey

“…Acidic cheese whey has limited usage due to the high salt concentration and acidity [4,5]. Through the production of 1 kg of cheese, 9 L cheese whey is formed [6]. Cheese whey production across the globe is 160 million tons [7].…”