Measurement of Airborne Contamination in Two Commercial Ice Cream Plants

Air in two commercial ice cream plants was sampled for microbiological and nonmicrobiological particles over a 4-month period. Sampling methods utilized Andersen two-stage and Ross-Microban sieve samplers, a Biotest RCS sampler, and a Met-one laser particle counter. Air was sampled two to three times per day in pasteurized mix storage, processing, and filling areas. Viable particle counts per 100 L air obtained with the Andersen sampler were 2.26 ± 0.47 (log₁₀ Mean ± S.D.), 2.05 ± 0.68 and 2.31 ± 0.46 in pasteurized mix storage, processing and filling areas, respectively. These levels were similar to those obtained using the RCS sampler, but they were significantly (p<0.05) greater than those obtained using the Ross-Microban sampler. Overall correlations of the RCS and Ross-Microban samplers with the Andersen sampler were r² = 0.69 and 0.56, respectively. Correlations between Andersen sampler results and the concentration of total particles greater than 0.5 μm were r² = 0.15 in pasteurized mix storage, 0.11 in the processing area, and 0.13 in the filling area.