The Comparison of Four Bioluminometers and Their Swab Kits for Instant Hygiene Monitoring and Detection of Microorganisms in the Brewery

Abstract

Four luminometers and their swab units were evaluated for detecting ATP by surface swabbing.Testing included pipetting known quantities of ATP directly onto the sivabs; pipetting known levels of bacteria and yeast directly onto the swabs and swabbing samples of bacteria and yeast from a surface. None of these instruments and swab detection kits provided consistent, reproducible detection ofATP standards or ATPfrom microorganisms even at high concentrations.All of the sivab kits/instruments shoived poor linearity in measuring known quantities of ATP and shoived high variability in ATP readings with replicate swabs containing identical concentrations of microorganisms. Since good linearity and reproducibility could be obtained using a liquid sample assay of ATP standards without swabs, it is suggested that the swab method itself may be unreliable. ATP may not be effectively released from microorganisms on swabs; ATP may adsorb to the swab interfering with detection and/or the swab might block light transmission. Sivabs of bacterial/yeast suspensions dried on a sterilized surface, provided the most inconsistent ATP readings and lacked linearity. A reason for the poor detection of microbial ATP by surface swabbing could be the inability to pick up microorganisms effectively.Key Words: ATP, bioluminometers, microorganisms, brewery, hygiene, swab. INTRODUCTIONpick up residual ATP and microorganisms followed by a step to release microbial ATP. Light produced from an All living cells contain ATP (adenosine triphosphate) enzyme-coupled assay is then measured in a luminometer which can be extracted and assayed using the enzyme and corre]ated directly to ATP levels in the original coupled luciferin/luciferase assayW-K This reaction sampie. Thjs reaction can be accomplished in seconds produces light (photons) which is directly proportional providing near instantaneous measurements of ATP. If a to the amount of ATP present in the sample^U8. The surface has been properly cleaned and sanitized there light output can be precisely measured in a luminometer should be little or no ATP present (free or contained or with a CCD camera"". Microbial and non-microbial withjn microorganisms). However, as residues from the ATP (which usually refers to free ATP not contained fermentation process and microorganisms are left within a microorganism) can be differentiated by first behind and/or are not removed during cleaning and measuring the free ATP in a sample followed by the sanitation, ATP levels are shown to increase. Therefore, enzymic destruction of the free ATP. Microbial ATP can tr,e method is theoretically very useful for assaying the then be released by lysing the microorganisms present in effectiveness of cleaning and sanitation, the sample and can be measured by the luciferin/ luciferase assay. However, for most surface hygiene Silliker Laboratories Group, Inc. investigated five monitoring, total ATP is measured by releasing all ATP different luminometers and found large differences in from microbial sources and measuring the fr...

How Reliable Are ATP Bioluminescence Meters in Assessing Decontamination of Environmental Surfaces in Healthcare Settings?

“…These results support earlier studies showing such a correlation [6], [8], [10], [11], [15], [17]–[19] [12], [14], [20], [21]. The observed correlations were slightly higher for the standard ATP solutions than those derived from S. aureus .…”

“…In 2002 in the US, 5% of all patients acquired such infections and of these, the mortality rate was nearly 6% [6] – [11] . In the United States alone, the cost of such hospital-acquired infections (HAIs) is estimated to be between 5 and 29 billion dollars annually [9] , [12] – [14] .…”

The uses and abuses of rapid bioluminescence-based ATP assays

“…Such measurements provide an indication of the quality of cleaning, but should not be interpreted as a direct indicator of microbial surface contamination. ATP hygiene monitoring has been used in a variety of food processing environments including dairy processing (Bell et al, 1994) and brewing (Carrick et al, 2001) to name just two. Studies where both ATP assays and microbiological plate counts were carried out simultaneously have yielded a level of agreement of about 70% in categorising passes and failures after cleaning (Griffiths, 1996).…”

“…In addition, insufficient attention has been paid to the effects arising from the poor repeatability and reproducibility inherent in the process of sampling at a surface using swabs. A further difficulty is that at low RLU readings the difference in sensitivity between luminometers may become apparent (Carrick et al, 2001). …”

Reliability Testing for Portable Adenosine Triphosphate Bioluminometers

“…A calibrated micropipette (Thermo Scientific) was used to apply the diluted ATP directly onto the swabs for each of the portable ATP bioluminometers, following an earlier method. 11 At each dilution point, each brand was tested in triplicate or more frequendy. The swabs for each brand were from multiple batches, stored in accordance with the manufacturers' recommendations, and used within the use-by dates.…”