strains, being intensely used in the dairy market, are particularly vulnerable
strains, being intensely used in the dairy market, are particularly vulnerable to users of the so-called 936 group of phages. commercial milk fermentations, and thus playing a vital part in the production of fermented products such as cheeses, buttermilk, and sour cream (Deveau et al., 2006). However, their widespread use is accompanied from the constant threat of (bacterio) phage assault and, despite continual study efforts into the prevention of phage illness, phage predation of lactococcal strains continues to be a problem. Illness by phages may result in lysis of the starter tradition which interrupts the fermentation process, reduces the quality of the end-product, and may even result in complete fermentation failure (Garneau and Moineau, 2011). Contributing to this danger is the intro of phages at numerous points in Pterostilbene IC50 the fermentation process, such as (i) the intake of natural milk, in which phages may reside (Madera et al., 2004; Atamer et al., 2009); (ii) re-introduction of processed fermentation by-products, such as recycled whey protein; (iii) movement of employees between different areas of the facility; (iv) the spread of phages throughout the flower via aerosols (Verreault et al., 2011); and (v) ineffective sanitization of products between fermentations. Significant technological and procedural improvements have been made in an attempt to control phage contamination. These include (i) heat treatment of milk via pasteurization; (ii) high pressure treatments; (iii) the use of strain rotations and so-called direct vat starters (DVS) to prevent the proliferation of phages, along with the concomitant development of phage-resistant strains for use in these rotations (Moineau, 1999); (iv) the improvement of dairy plant facilities, such as plant design optimization and the use of closed vats (Allison and Klaenhammer, 1998); and (v) the utilization Rabbit Polyclonal to CHST10 of commercial chemicals for the sanitization and disinfection of flower equipment and facilities. While these strategies have been relatively effective, with complete product loss now very rare (Madera et al., 2004), phage-associated fermentation issues are still a very common event in dairy vegetation, probably because phages have adapted to conquer one or more of the Pterostilbene IC50 imposed hurdles (Atamer et al., 2011; Mercanti et al., 2012; Murphy et al., 2014). In dairy processing vegetation, sanitization between fermentations is definitely a critical step in the control of phage contamination. This involves detailed cleaning in place (CIP) procedures, utilizing purpose-made chemical sanitizers for the physical and chemical removal of phages and Pterostilbene IC50 additional microbial contaminations (Cords et al., 2001). For biocides to be Pterostilbene IC50 considered eligible for use in the dairy market a number of criteria must be met, such as ease of use, cost effectiveness, lack of impact on the security of workers and the final product and, of course, its anti-microbial effectiveness (Guglielmotti et al., 2011). The application of food contact sanitizers is highly regulated (Wessels and Ingmer, 2013). For example, in Europe, sanitizers must have a shown ability to reduce phage figures by at least four logs under recommended test conditions before they can be deemed suitable for phage inactivation (Western Committee for Standardization (CEN), 2002). Food contact sanitizers employ a range of active chemical agents, such as quaternary ammonium compounds, chlorine compounds, hydrogen peroxide, and iodine compounds (Gaulin et al., 2011), with many of these agents having been in use as disinfectants and preservatives for many decades or even hundreds of years (McDonnell and Russell, 1999). The precise mode of action of many antimicrobial compounds on bacteria has been widely analyzed, with much right now known about the specific focuses on and anti-bacterial mechanisms of many biocides (McDonnell and Russell, 1999; Maillard, 2002; Wessels and Ingmer, 2013). In contrast, relatively scarce data currently exists pertaining to the virucidal mode of action of biocides (Garneau and Moineau, 2011; Murphy et al., 2014). However, while exact structural focuses on in phages are, as yet, largely uncharacterised, several studies have been performed within the effectiveness of phage inactivation by commercially used biocides. For example, a number of studies have been performed on the effectiveness of peracetic acid and sodium hypochlorite as virucidal providers (Binetti and Reinheimer, 2000; Capra et al., 2004; Avsaroglu et al., 2007). Quaternary ammonium compounds have also proved effective (Campagna et al., 2014), as offers sodium hydroxide (Murphy et al., 2014). However, despite the verified effectiveness of these biocides, phages continue to persist in dairy facilities, and a possible contributing factor to this may be variations and/or raises in phage resistance to biocides. The current study assessed the effectiveness of a range of commonly used sanitizers in the neutralization of lactococcal phages of the industrially significant 936.