PRELIMINARY REPORT ON THE USE OF AIROFRESH UNITS IN CHILLED CHEESE MATURATION FACILITIESMarch 5 , 2018
2 AiroFresh® 1000 units were installed in a ~ 170m3 maturation room that is used to mature blue cheese. The room was emptied and thoroughly cleaned before use. Cheese was then loaded back into the room. The cheese is stored on stainless steel hurdles. The room temperature is controlled and the air humidity is very nearly saturated. As fresh cheese is made it is loaded into the room where partially matured cheese is located. After the required maturation time cheese is removed. Thus, the room is regularly opened and closed as fresh cheese comes in and matured cheese goes out.
Testing of the units was via air sampling and air plates. Air sampling involves using an apparatus to suck in a known volume of air and capturing the microorganisms present in the air onto an agar plate. Air plates involve leaving agar plates open in the maturation room for a fixed time. In both cases the plates were then incubated in our laboratory and the microorganisms counted. Once a steady state was found the AiroFresh® 1000 units would be removed to see what happened to the count. The results are recorded as Colony Forming Units (CFU)/time-period or air volume
The results for air sampling were clear and conclusive.
It is quite clear that the 2 AiroFresh® 1000 units dramatically reduce airborne contamination. If we average the last 4 weeks of results we can see that within 2 weeks the yeast and mould count has dropped to < 70 CFU or by more than 80%. As a background, counts in 6 other maturations rooms were 82, 133 CFU to TNTC (Too Numerous To Count). Indeed, the results in the graph above after the units were removed were TNTC but are recorded as a 1000 CFU as essentially TNTC = greater than 1000 CFU.
What this suggests is that the starting count in a maturation room is a function of how well it was cleaned and how long since it was cleaned. The AiroFresh® equipment then reduces the count by > 80%. When the units are removed the count goes back up. This suggests that using AiroFresh® 1000 units maintains the rooms as if it had just been cleaned. It thus seems likely that the frequency of required cleaning could be significantly reduced
The air sampling results from the maturation room were also conclusive. The sample was taken 2 hours after the door was closed via a remote-control unit
The trial will be repeated with an added step of using additional AiroFresh® units in the corridor outside the maturation room. This will determine if further reduction of the yeast and mould count can be achieved in the maturation room.