ATP bioluminescence can evaluate cleaning and sanitizing ATP bioluminescence can evaluate cleaning and sanitizing effectiveness in the milking parlor effectiveness in the milking parlor

Four areas of the milking parlor were evaluas colony forming units per area or volume ated for effective cleaning and sanitation using (CFU/cm or ml). The downfall of this techtotal aerobic counts (standard plate count) and nique is that it only measures the number of ATP bioluminescence (ATPB) techniques. aerobic microorganisms and not the presence of Whereas the plate counts only monitor bacterial soil or food residue. This microbial technique is numbers, the ATPB results (reported as relative time consuming (24 to 48 hr before results are light units, RLU) also indicate residual soil or available), requires a fair amount of knowledge, food residue on the surface. Results showed and is expensive (both reusable and nonreusable little correlation between the RLU values and the equipment and resources are necessary). aerobic plate count data; however, the ATP bioluminescence technique detected the presence The ATP bioluminescence (ATPB) system is of soil residue on the contact surface. The ATP relatively new. Currently, this technology is bioluminescence system is a fast (<2 min) and used to monitor sanitation effectiveness in food simple method that evaluates the effectiveness of processing plants. The ATPB monitors both cleaning and sanitation procedures employed. microbial loads and food residue but fails to


M. J. Meyer and K. A. Schmidt
Summary number of microorganisms on the surface (TPC Four areas of the milking parlor were evalu-as colony forming units per area or volume ated for effective cleaning and sanitation using (CFU/cm or ml). The downfall of this techtotal aerobic counts (standard plate count) and nique is that it only measures the number of ATP bioluminescence (ATPB) techniques.
aerobic microorganisms and not the presence of Whereas the plate counts only monitor bacterial soil or food residue. This microbial technique is numbers, the ATPB results (reported as relative time consuming (24 to 48 hr before results are light units, RLU) also indicate residual soil or available), requires a fair amount of knowledge, food residue on the surface. Results showed and is expensive (both reusable and nonreusable little correlation between the RLU values and the equipment and resources are necessary). aerobic plate count data; however, the ATP bioluminescence technique detected the presence The ATP bioluminescence (ATPB) system is of soil residue on the contact surface. The ATP relatively new. Currently, this technology is bioluminescence system is a fast (<2 min) and used to monitor sanitation effectiveness in food simple method that evaluates the effectiveness of processing plants. The ATPB monitors both cleaning and sanitation procedures employed. microbial loads and food residue but fails to (Key Words: Milking Parlor, HACCP Plan, tation program relies on the cleanser to remove Sanitation, ATP Bioluminescence.) soil and food residue and the sanitizer to kill

Introduction
(training time of 30 min) and produces results Cleanliness of the milking parlor is very downfall of the ATPB is that nebulous values are important in maintaining high quality raw milk. generated and referred to as relative light units Although most people think of bacterial as being (RLU). Each user must develop his or her own the main determinants of raw milk quality, other RLU limits to designate "clean", "warning" factors, such as cleanliness and protein quantity, (values are elevated and may indicate some can have an effect. Generally, as raw milk contamination), and "dirty" zones (values are quality decreases, shelf life and usefulness also too high and the surface needs to be recleaned). decrease. Because milk from a healthy animal contains little, if any, microbial contamination, A milking parlor environment is very differany surface that milk contacts is a potential con-ent from a food plant environment. But with the taminating source.
increased concern for food safety, consumers The typical way to monitor the cleanliness of (Hazard Analysis Critical Control Point) plans an area is to swab its surface and then use plating be considered and possibly established to start at and incubation techniques to enumerate the the "farm" and end at the "plate". In this situa-or total plate count). These values are reported 2 distinguish between the two. An effective sanimicroorganisms. The ATPB is relatively simple within 2 min of swabbing a contact surface. The and legislators have suggested that HACCP tion, it will be important that sanitation proce-England) was used. For these samples, Biotrace dures can be verified in a milking parlor, so that Uni-Lite swabs were used on adjacent areas of milk contact surfaces do not contaminate the the microbial swabs. These Uni-Lite swabs milk. As with all verification procedures, ob-were placed back into their carriers, activated by taining results quickly and accurately is impor-an enzyme solution. The end products of this tant. Thus, the question was asked, can the reaction produce light, which is sensed by the ATPB be used to ascertain cleaning and sanita-hand held Uni-Lite Xcel Luminometer, genertion effectiveness in the milking parlor?
ating the RLU value within 45 seconds. The Procedures crobes, food residue, or soil) is present on the Four milk contact areas were identified in the milking parlor located at the Kansas State Biotrace designates the following ranges: University Dairy Teaching and Research Center.
acceptable--less than 250 RLU (clean surface) Location A was the inside of a rubber inflation and unacceptable--greater than 300 RLU (dirty liner on the milker claw. Location B was the surfaces). Values between 250 to 300 RLU inner surface of the milk filter canister. Location would be in the questionable zone. These limits C was the inside of the milk line going into the adequately evaluate sanitation in a food processmilk tank, and location D was the interior of the ing operation. refrigerated bulk tank. For locations A, B and C, swabs were taken after running the 7-minute Results and Discussion sanitizing cycle using common Clorox® bleach (500 mL) as the sanitizing agent. Swabbing of Preliminary work showed that we could these locations was done 10 min after the sanitiz-obtain accurate and precise results. For swabs ing cycle was completed. Location D was from clean, sanitized surfaces, RLU values were cleaned independently, by an automatic bulk low, and microbial counts generally were not tank cleaning system. On two sample dates, detected. In addition, the results agreed with swabbing was done 15 min after the tank had previous research. No correlation was detected been sanitized on the hot acid wash cycle. On between the microbial counts and RLU values. the other sample date, the bulk tank contained The only apparent trend was that swabs from raw milk at 2.8EC or 37EF. dirty surfaces had higher RLU values and CFU/ml (in certain circumstances) counts than Over a 17-day period, the four locations did swabs from clean surfaces. (either 2.5 cm or 5 cm ) were swabbed with a 2 2 sterile cotton swab moistened with sterile Thus, three different scenarios from the peptone broth. These broth samples were refrig-milking parlor are shown and discussed. Beerated, transported to the KSU Dairy Plant cause the experimental conditions vary, results Laboratory, and analyzed for total number of are shown independently and not combined. aerobic microorganisms (TPC) following stan-Results of our three trials are shown in Tables 1, dard procedures using Petrifilm®. The TPC 2, and 3. values were standardized and reported as the number of colony forming bacteria/ml of sample (CFU/ml).
Results varied considerably. Table 1 No accept or reject limits exist for TPC before swabbing. All RLU values are less than values for food contact surfaces; however, the 250, indicating a thorough cleaning and sanitizgeneral rule is the lower, the better. For a dairy ing. The TPC results produced no growth, processing plant, TPC values of greater than 100 indicating an effective sanitation program. CFU/ml are potentially problematic and require Considering both sets of data, we concluded that recleaning.
the milking equipment and raw milk bulk tank To evaluate the ATPB system, the Biotrace should not add contaminants to the raw milk. Uni-Lite Xcel Luminometer (Biotrace, Ligend, TM TM TM TM higher the value, the more contamination (mifood contact surface.
depicts the results of cleaning and sanitizing had been cleaned and sanitized adequately and Note that the two different tests produced differ- The results for locations B and C (  Table 2 indicate that locations A contaminated than a surface with 100 CFU/ml. and B would pass a cleaning/sanitation inspec- The same cannot be said about RLU values. A tion from either a TPC count or an RLU value.
surface with 900 RLU is not necessarily more Location C would not pass an inspection from dirty than a surface with a 350 RLU reading. either test, but location D would pass by the TPC count, but not by the RLU value. This will be This technology still can be used to distinexplained further.
guish between clean and dirty surfaces. At this When these two situations are considered be used to quantitate the amount of contaminaindependently, the RLU value at location C tion or microbes on a surface. In this case, if the indicates that this surface is not clean and should RLU values were over 300, the TPC counts be recleaned before using. The TPC data indi-either indicated that poor sanitation occurred, or cate that the counts are less than 250 CFU/ml. we knew that it was a "dirty" surface. Thus, we Microbial counts between 100 to 250 CFU/ml conclude that the ATPB can be used to evaluate would warrant that this piece of equipment be the sanitation effectiveness in the milking parlor. recleaned before milk runs through this pipe. The TPC results required 48 hours to obtain.
Conclusions Obviously, milk would have run through this pipe before the results were available. Quick This work indicates that the ATPB system is turn-around of cleaning might have prevented useful to monitor appropriate cleaning and contamination of raw milk. sanitation programs. If either step is overlooked, Location D produced mixed results. TPC guidelines of <250 as acceptable and >300 as results show a sanitized milk tank, whereas the unacceptable seem to hold true for the milking ATPB results indicate dirty surfaces in the bulk parlor as well as a food processing plant. The tank. This scenario illustrates that milk residue advantages of the ATPB method are its speed is measured by the ATPB system, but not the (less than 5 min) and ease (minimal instructional TPC. The TPC results show only microbial time). As HACCP farm to plate plans are realcontamination, but the RLU value indicates ized, this technology may provide a viable, easy microbes (apparently minor) and residual dirt or method to verify adequate cleaning and sanitamilk left on the surface. Based on both sets of tion procedures. results, we could conclude that sanitation may have occurred, but the cleaning step was omitted.