| Summary: | 碩士 === 國立屏東科技大學 === 食品科學系 === 94 === Dairy manufactures must not rely solely on pasteurization to protect product safety, but must evaluate their entire processing operations with a view to maximizing product protection from microbial contamination at all points. 35% post-pasteurized contamination come from fresh milk products contaminated with pipelines, filling nozzles, pump, and product storage tanks, the other 65% post-pasteurized contamination come from the environment situation of the packaging area. The personal hygiene of the operator and airborne quality are key points to avoid post-pasteurized contamination.
The objective of this study was to evaluate the effects of air quality situation on the cleanliness zone of filling machine environment, such as airborne particle counts, airborne microbial colonies, temperature, and humidity, and the comparison of air quality improvement with or non clean room was also included.
The evaluation of total particles on the position of the air conditioner outlet, the upper side on filling machine, and the beside of the filling nozzles were counted using a model CI-500 particle counter (Climet Co.), the total particle counts (sizes ≧ 0.5μm) were 5.83 ± 0.35( log Mean ± SD),5.80 ± 0.35, 5.84 ± 0.37 particles/ft3. After the installation of the clean room with high efficiency particulate air filter, the total particle counts (sizes ≧ 0.5 μm) were 3.81 ± 0.38,2.08 ± 0.58, 3.52 ± 0.34 particles/ft3, the condition was significantly improved (P<0.01), it was the same result on the particle sizes≧5 μm. The evaluation of total microbial colonies on the above position, airborne microbial colonies were very significantly improved (P<0.01) than that of non clean room, it could meet the criterion of the Good Manufacturing Practice (airborne microbial colonies less than 30 CFU/5 min).
Bacterial test of the product buffer tank, the swab test of the filling nozzles and the operator’s hands were tested, the total bacterial counts and coliform bacterial inspection were qualified, the condition with or non clean room were not significantly different (P>0.05) in this field.
The total bacterial counts of the products stored at 4ºC and 10ºC for 1, 5, 10, 15, 20 days were tested, the result showed that the less in total bacterial counts after the clean room installed. The total bacterial counts and coliform bacterial of the products stored at 4ºC for 1, 5, 10, 15, 20 days were met the standard criterion. After the clean room installation, the bacterial counts of the products could meet the standard criterion while the products were stored at 10ºC for 15, 20 days.
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