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While able to grow in the presence of hops, the presence of hops still inhibits ''P. damnosus''. For example, one study found that in the presence of 15 IBU, lactic acid production was reduced by ~82%. Exposure to 15 IBU also increased diacetyl production by 350%, while 2,3-pentanedione (buttery, nutty, toasted, caramellic, diacetyl and acetoin notes <ref>[http://www.thegoodscentscompany.com/data/rw1003991.html "acetyl propionyl ". The Good Scents Company. Retrieved 01/18/2017.]</ref>) was decreased by 25%. Interestingly, exposure to 3% ABV and no hops reduced the production of diacetyl and 2,3-pentanedione by about 20%. The addition of vitamins, specifically thiamine (vitamin B1) and riboflavin (vitamin B2), increased the production of lactic acid in the presence of 15 IBU or no hops by about 15-30%. However, thiamine also increased diacetyl production by 100-125% and 2,3-pentadione production by 20-30% without the presence of hops. In the presence of 15 IBU, thiamine and/or riboflavin increased diacetyl production by about 26-36% and 2,3-pentadione by about 40-114% <ref>[http://onlinelibrary.wiley.com/doi/10.1002/jib.385/full The influence of thiamine and riboflavin on various spoilage microorganisms commonly found in beer. Barry Hucker, Melinda Christophersen, Frank Vriesekoop. 2017.]</ref>. Strains that are grown exposed to small amounts of iso-alpha acids can be adapted to survive higher amounts up to ~150 μg mL<sup>1</sup>. The implications of this in brewing mean that the bacteria can enter any stage of the process and remain in undetectable amounts until it adapts to higher IBU conditions and then potentially spoils beer <ref name="Garcia-Garcia" />.
====Mixed Culture Influence====
See [[Lactic Acid]].
===Carbohydrate Metabolism===
===Other Metabolites===
''P. claussenii'' tends to produce a smaller amount of acetic acid than lactic acid in about a 1:3 ratio. ''P. damnosus'' tends to produce only lactic acid and no acetic acid <ref name="Geissler">[http://www.sciencedirect.com/science/article/pii/S0168160515301033 Metabolic strategies of beer spoilage lactic acid bacteria in beer. Andreas J. Geissler, Jürgen Behr, Kristina von Kamp, Rudi F. Vogel. 2015.]</ref>, although some strains have been found to produce small amounts of acetic acid of around 100-300 ppm. This level is slightly below and above flavor thresholds in lager beer (but could be additive with other organisms) <ref>[http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2010.tb00393.x/abstract Isolation, Identification, and Characterisation of Beer-Spoilage Lactic Acid Bacteria from Microbrewed Beer from Victoria, Australia. Garry Menz, Christian Andrighetto, Angiolella Lombardi, Viviana Corich, Peter Aldred, Frank Vriesekoop. 2010.]</ref>, but significantly less than the total acetic acid often found in gueuze (around 700-2200 ppm <ref>[http://www.horscategoriebrewing.com/2016/07/duivelsbier-of-halle.html Jansen, Dave. Hors Category Blog. "Duivelsbier of Halle". 07/30/2016. Retrieved 01/31/2018.]</ref>) and Flanders reds (300-2300 ppm <ref>[http://www.sciencedirect.com/science/article/pii/S0168160515301896 Microbial diversity and metabolite composition of Belgian red-brown acidic ales. Isabel Snauwaert, Sanne P. Roels, Filip Van Nieuwerburg, Anita Van Landschoot, Luc De Vuyst, Peter Vandamme. 2015.]</ref>). ''Pediococcus'' also carry carries the decarboxylase enzyme (PAD) which converts hydroxycinnamic acid (ferulic acid) into phenols (4-vinyl guaiacol) <ref name="lentz_2018">[http://www.mdpi.com/2311-5637/4/1/20/html#B13-fermentation-04-00020 The Impact of Simple Phenolic Compounds on Beer Aroma and Flavor. Michael Lentz. 2018. doi: 10.3390/fermentation4010020.]</ref> ===Mixed Culture Influence=== See [[Lactic Acid]].
==Storage==