Breathable Bag Material: polythene. Sterilizer Temperature:atmospheric pressure(100℃)
polypropylene.Sterilizer Temperature: autoclave(123℃-126℃).
Breathable Polypropylene bags with filters
Breathable polypropylene bags with different filter types are widely used for spawn production. In farms where spawn is produced for farm use, a stand up bag is generally used. Small bags of 10 by 8 by 30 cm gusseted with a filter 10 cm down from top are common. Larger bags with a 20 by 12 cm foot print and 50 cm high are also commonly used.
For Agaricus spawn, grain spawn, filters of the PP non woven with PP membrane are used. The filter are low gas transmission filters that retain CO2 . A preferred filter size is 0.2 micron.
Shiitake and pleurotus and most specialty mushrooms prefer a higher gas exchange filter.
Filter size remain at 0.2 or lower, but the efficiency of the filter (larger number of pores per unit area) allow higher gas exchange. By using PP bags and filters, substrate is autoclaved in these bags, and because these bags are of higher cost and more spawn is produced per bag, a more reliable bag must be fabricated. With PP resin, different proprietary raw material mix is used to modify PP to reduce oxidation and add to the PP resin a modifier to make the final autoclaved bag retain impact strength, or more stretch. Thus modified, bags will less likely have holes, and sealing temperature is widened.
It is also important to have a clear bag to observe any instance of contamination. Some bag fabricators use a special resin developed for hospital waste, this resin increases sealing temperature and reduce clarity, thus not a desirable bag for spawn production. By reducing oxidation, PP film retains its original properties and less hydro carbon gas is given off.
Breathable Polyethylene bags with filters
Breathable PE bags with filters are much used in spawn production. Because these bags are not autoclavable, sterilization is by irradiation. It is noted here that if PP is irradiated, PP disintegrates. PE filtered bags are often used by large spawn producers in sizes of 35 by 60 cms. Large spawn producers often use bulk sterilization of grain spawn. This is done by sterilizing the grain in jacketed mixers which heat and cool in fast cycles and grain introduction into the already sterilized and cooled by proprietary methods and then mixed. The mixed, and spawned substrate is filled into the PE bags and sealed to incubate. Apart from fast cycles, the finished PE bags have a smooth surface unlike PP spawn bags are often dented by protrusion of grain during autoclaving. However, the bulk sterilizing is very expensive and difficult to maintain.
Filters for these bags can be PE non-wovens like Tyvek, or other proprietary PE non wovens and membranes. PP filters can also be laminated to PE by introducing an intermediary non woven that heat sealable on PP and PE. Most PE bags with filters use a large panel of filter material but instead of a large hole cut in the bag below the filter, under the large panel sealed within the panel of filter is a series of small holes. The size of the holes are very critical to allow low evaporation of humidity, and yet give the spawn fast growth. If a large hole is cut under the filter. There usually is an area below the filter that humidity is low and no colonization results, and at times, this is a considerable amount of loss to the user. The large panel of filter distributes gas exchange over a large area, and is the guarantee for fast and uniform spawn colonization.
Breathable Bags with Filter's Technical Data
1)100*80*350mm, thickness 0.05
Filter size is 0.2micron or 0.5micron. The size of the bag could be customized.