Why do my Enoki bottles get contamination so easily?

Enoki is more contamination prone than oyster because it is grown on a sterilised, nutrient rich substrate, and rich sterilised substrates are very attractive to competing moulds and bacteria if any get in. Unlike oyster on pasteurised straw, an Enoki substrate that is not fully sterilised, or that is contaminated during inoculation, will quickly grow green or other moulds. The main fixes are full proper sterilisation of the substrate and bottles, inoculation in a very clean space such as under a laminar flow hood or a good still air box, clean tools and hands, fresh pure spawn, and a clean cool grow room. The slow cold cycle also gives contaminants a long window, so any lapse shows up. Keep batches small while you tighten your sterile technique, and discard contaminated bottles immediately. Hands on training in sterile work from DMR Solan or an SAU will help most.