Microbiology Session
Amanda (Mandy) L Miller, Colorado State University, Fort Collins, CO USA
Co-author(s): Marisa Bunning, Martha Stone, Doreene Hyatt, and James
ZumBrunnen, Colorado State University, Fort Collins, CO, USA
ABSTRACT: Pathogenic bacteria have little chance of
surviving in beer due to intrinsic antimicrobial hurdles; however, there
are other microorganisms capable of persisting in the environment and
causing undesirable changes that spoil beer. The quality of all food
products including beer is affected not only by the integrity of raw
materials and cleanliness of the equipment and packaging materials, but
also by the purity of the environmental air surrounding the processing
area. Bottling and canning lines in breweries often are considered
non-closed production equipment and have the ability to become
contaminated from outside sources, including the environment. The
purpose of this project was to examine the environmental microbial air
quality within various areas of a craft brewery with emphasis on
potential beer spoiling bacteria. Air samples were collected inside and
outside the brewery to establish a baseline of data, identify areas of
concern, and examine the effects of seasonality. Areas of concern then
were sampled more often based on the risk of product contamination. The
air was sampled 307 times over 22 months using an automated impaction
sieve sampler pulling 80 L of air, and samples were plated both
aerobically and anaerobically. Aerobic results were used to evaluate
general cleanliness, while anaerobic testing was included to assess the
prevalence of beer spoiling organisms. The canning line within the
brewery was identified as a specific area of concern and was predicted
to be contaminated with beer spoiling bacteria an average 75% of the
time. Seasonality impacted aerobic microorganism levels, with fivefold
increases observed in the spring. The results of this study revealed
that testing for airborne microorganisms is highly recommended in the
craft brewing industry. Critical areas in the brewery, such as the
bottling and canning lines, should be routinely tested for airborne
microorganisms to prevent final product contamination.
Amanda
(Mandy) Miller received an M.S. degree in food science, with an emphasis
on food safety, from Colorado State University in Fort Collins, CO, in
2011. In 1999, she began working at New Belgium Brewing Company in the
Quality Assurance Department. After 10 years working as a quality
assurance analyst, she now holds the position of beverage safety and
sanitation specialist within the Risk Management and Environmental
Affairs Department. She has been a member of ASBC for more than 10 years
and a member of MBAA for more than 5 years.
VIEW PRESENTATION 162