Improving Quality and Safety of Dairy Products: A Supply Chain Approach

Andreia Bianchini Author

02/09/2021 Added

15 Plays

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Presentation given at WADPFR Winter Conference describing research related to dairy conducted at UNL.

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[00:00:01.121]Hello, everyone.
[00:00:02.670]First of all, I would like to thank Jeff
[00:00:05.020]for inviting me to share our research
[00:00:08.340]during this field rep conference.
[00:00:10.593]It is a great pleasure to be here
[00:00:13.294]and share with you all the research that we've done
[00:00:16.620]at the University of Nebraska-Lincoln,
[00:00:18.230]that is related to the quality and safety of dairy
[00:00:21.210]in the milk production and processing chain.
[00:00:24.170]Over the years, we have looked at production farms
[00:00:27.150]and processing facilities,
[00:00:28.827]and the combining formation has led us to believe
[00:00:31.670]that there are some interventions
[00:00:33.130]that could be applied at farm levels
[00:00:35.850]that would be beneficial
[00:00:36.918]in reducing spore formers associated with milk.
[00:00:40.630]And also, that improved cleaning and sanitation protocols
[00:00:44.530]can be extremely beneficial to the safety of dairy products.
[00:00:49.600]Our research group at UNL,
[00:00:52.120]has done over the years research that may contribute
[00:00:55.325]to improved quality and safety of dairy products
[00:00:59.470]throughout the dairy processing chain
[00:01:01.340]that we have represented here.
[00:01:03.660]We have investigated agricultural practices and strategies
[00:01:08.320]to reduce mycotoxin in grains,
[00:01:10.440]which in turn leads to improved safety in dairy products,
[00:01:14.150]specifically related to aflatoxins.
[00:01:17.100]Also, we have looked at practices
[00:01:19.150]and protocols at farm level
[00:01:21.192]that may lead to reduction of spore formers
[00:01:23.920]associated with dairy products.
[00:01:26.460]And while we're investigating the processing chain
[00:01:28.890]and how spore formers are associated with it,
[00:01:32.460]we have conducted a systematic review
[00:01:34.960]followed by a meta-analysis of information
[00:01:37.870]that we could find available in the literature
[00:01:40.200]to better understand the distribution of spore formers
[00:01:42.896]throughout the chain.
[00:01:44.690]Also, we have looked into processing facilities
[00:01:48.130]in regards to improving dairy quality
[00:01:50.660]related to spore formers,
[00:01:52.320]and also safety of dairy products related to Listeria.
[00:01:57.290]Today, I will focus in a few of this projects
[00:02:01.430]to share in more details with you all.
[00:02:03.890]Starting with improving quality
[00:02:05.930]in the dairy processing chain,
[00:02:07.920]let's first establish why spore formers
[00:02:11.579]are of concern in this processing chain.
[00:02:15.778]Spore formers are heat resistant,
[00:02:18.860]so they survive pasteurization processes,
[00:02:22.400]and may cause issues during the shelf life of dairy products
[00:02:26.440]by producing enzymes that can cause quality defects
[00:02:30.690]and also spoilage.
[00:02:32.330]The two main genus that are associated with this problems
[00:02:36.960]are Bacillus and Paenibacillus.
[00:02:39.030]And among these organisms,
[00:02:41.270]we can find psychrotrophic, mesophilic
[00:02:44.520]and thermophilic strains,
[00:02:46.130]which means that they can grow at refrigeration,
[00:02:49.400]ambient or higher temperatures.
[00:02:52.507]In general, the psychrotrophic spore formers
[00:02:56.460]limit the shelf life of fluid milk,
[00:02:59.940]because of their ability to grow
[00:03:01.500]under refrigeration conditions,
[00:03:03.440]even though they're usually found in milk at very low levels
[00:03:07.240]at the beginning of the shelf life.
[00:03:09.340]And the mesophilic and thermophilic spore formers
[00:03:12.342]are usually found at higher levels in fluid milk,
[00:03:16.350]and then may affect the quality of powdered products.
[00:03:20.420]For in these products, limits on spore former counts
[00:03:24.220]are applied nationally and internationally,
[00:03:27.310]and in order to produce powders
[00:03:29.540]that are acceptable to these markets,
[00:03:33.080]the level of spores in milk must be as low
[00:03:36.100]as 10 to 50 colony forming units
[00:03:39.780]per mil of the raw fluid milk.
[00:03:43.760]And from research and literature,
[00:03:46.430]we know that these microorganisms have been associated
[00:03:49.460]with every aspect of the farm.
[00:03:52.540]The feed that is used, the fecal material,
[00:03:55.177]raw milk, teats, soil and bedding,
[00:03:57.730]everywhere in the farm, we can find these organisms.
[00:04:00.890]And indeed, in Nebraska,
[00:04:02.720]we were able to verify the occurrence of these spore formers
[00:04:06.370]in association with all the different areas of the farm,
[00:04:10.060]as we can see here in this chart.
[00:04:12.000]The levels that were found initially in raw milk,
[00:04:15.770]and also in milk that had been pasteurized
[00:04:18.300]and stored for 21 days.
[00:04:23.040]We also can see in this chart,
[00:04:25.100]that some areas of the farm, like the pens, for example,
[00:04:30.260]have higher levels of spore formers
[00:04:33.202]when compared to the parlor,
[00:04:35.850]which is usually a cleaner environment,
[00:04:38.360]but nonetheless, not free of spore formers.
[00:04:41.800]If environmental samples are taken
[00:04:44.320]from processing facilities, dairy processing facilities,
[00:04:47.830]we still can find spore formers.
[00:04:49.890]And most importantly,
[00:04:51.250]these spore formers are able to survive pasteurization,
[00:04:55.662]and can be found on pasteurized samples
[00:04:59.270]after 21 days of storage.
[00:05:01.650]So, by isolating those microorganisms
[00:05:04.690]that were found in pasteurized milk
[00:05:08.440]and looking at their genetic profile,
[00:05:10.900]we were able to find their sources.
[00:05:13.870]and we matched those,
[00:05:16.340]we found the source by matching the sequence
[00:05:18.448]of a specific gene.
[00:05:21.190]In this case, we were studying the rpoB gene.
[00:05:24.510]So, isolates that were obtained from fluid pasteurized milk
[00:05:28.802]were then matched to those collected
[00:05:30.980]throughout the fluid milk chain,
[00:05:33.260]helping us identify the source.
[00:05:35.000]And here, in this slide,
[00:05:36.500]we can see all the different spore formers
[00:05:39.210]that were tied back all the way to the farm environment,
[00:05:42.870]the ones that were tied back to the raw milk
[00:05:45.810]that had been supplied to a processing facility,
[00:05:49.610]and those organisms that were tied back
[00:05:54.340]to the different areas of that processing facility,
[00:05:58.555]like tanks and the bottling machine.
[00:06:02.113]So we know that the issue persists throughout the chain.
[00:06:05.900]Let's look now further,
[00:06:07.710]by taking a backwards approach to the processing chain,
[00:06:11.410]starting at the processing facilities.
[00:06:15.290]In Nebraska, we conducted a study
[00:06:17.280]involving a facility that produces evaporated milk.
[00:06:22.363]This facility receives milk from several farms in Nebraska,
[00:06:27.600]and in this particular project,
[00:06:29.660]we were interested in understanding
[00:06:31.630]the fact of the processing steps
[00:06:34.359]on the levels of spore formers.
[00:06:38.190]Based on the data that we collected,
[00:06:40.610]the amount of spores associated with the product
[00:06:42.924]increased with each step,
[00:06:45.640]with average contamination going from less than 1 log CFUs,
[00:06:52.050]colony forming units, per mil of raw milk at the farm,
[00:06:55.745]to about 2 log CFU per mil after condensation of the milk.
[00:07:02.580]Now, if we compare those values
[00:07:04.500]with the expectations of the market,
[00:07:06.690]we need to take into account the condensation step
[00:07:10.080]going from condensed milk to dry powder milk.
[00:07:14.560]So if we look at the market expectations from dry powder,
[00:07:18.995]we have values of 2.7 log CFU per grams.
[00:07:24.550]And if we consider the amount of water
[00:07:26.940]that is removed from condensed milk to dry powder milk,
[00:07:30.520]the levels that we would expect in that condensed milk
[00:07:33.280]should be 2.1 log CFU.
[00:07:36.870]And then in the pasteurized milk, 1.7 log CFU.
[00:07:42.690]As we can see here in the chart,
[00:07:45.920]for the most part, the levels that we found in the products
[00:07:49.370]were below that market expectation.
[00:07:52.080]But the issue is that those were the average values.
[00:07:56.320]If we consider the standard deviation,
[00:07:58.980]we have plenty of product
[00:08:00.810]that would not meet market expectations.
[00:08:04.030]So, in looking for other factors
[00:08:06.970]that may also be contributing to the problem,
[00:08:10.080]we did a systematic review and meta analysis of data
[00:08:14.030]that was available in the literature
[00:08:15.510]associated with spore formers
[00:08:17.350]at different stages of that dairy chain.
[00:08:20.258]And from all the papers
[00:08:22.130]that met the criteria for inclusion in this research,
[00:08:25.540]we were able to create plots, like this one shown here,
[00:08:29.490]that tell us the prevalence of spore formers
[00:08:34.720]throughout the milk chain.
[00:08:36.139]And we can see here,
[00:08:38.650]the information goes from milking machines at the farm,
[00:08:43.008]raw milk tanks at the farm,
[00:08:45.400]and then transportation, so raw milk at a tank,
[00:08:51.690]and then transportation,
[00:08:53.131]silos at a processing facility,
[00:08:55.593]then pasteurized milk at a processing facility,
[00:08:58.820]and packaged milk at processing facilities.
[00:09:02.440]So, the red dark line here
[00:09:07.320]summarizes the means that were found
[00:09:11.580]based on the random effects of the meta analysis.
[00:09:15.410]And the dots sizes that we have in each of this points
[00:09:19.620]represent the number of data points that we have
[00:09:21.837]that were associated with those.
[00:09:23.870]And as we can see, on average,
[00:09:26.538]the prevalence of spore formers,
[00:09:29.130]in other words, the percentage of samples
[00:09:31.510]that are contaminated with spore formers
[00:09:33.730]increases as that milk travels
[00:09:36.361]throughout that processing chain.
[00:09:40.120]Another chart that was generated based on that research
[00:09:46.510]is the one that I'm showing here.
[00:09:48.200]This one now demonstrates or show us
[00:09:51.270]the concentration of spore former bacteria
[00:09:54.072]through out that very same milk processing chain.
[00:09:57.830]So, the red dark line, again,
[00:10:01.510]shows the average values for the concentration,
[00:10:06.060]colony forming units per mil of milk
[00:10:10.950]as the milk moves throughout that chain.
[00:10:14.920]Another thing that we were able to calculate
[00:10:16.930]based on this data,
[00:10:18.160]was the percentage of contribution
[00:10:21.070]from each of those different steps,
[00:10:23.320]to the final amount of spore formers that we had
[00:10:26.820]in the pasteurized milk that was coming out
[00:10:29.940]of the packaging or the bottling machines.
[00:10:33.050]So if we look at those contributions,
[00:10:36.590]about 25% were added to the product during processing.
[00:10:43.360]About 37.5 were added to the product during transportation,
[00:10:48.960]and 37.5 were already there to start with,
[00:10:53.580]from the farm environment.
[00:10:55.430]So, because a significant proportion of the spores
[00:10:58.420]are coming from the farm environment,
[00:11:00.600]we have also focused some efforts
[00:11:02.800]in evaluating the problem at farm level.
[00:11:05.828]And that brings us to this step in the processing chain,
[00:11:11.480]the dairy farm.
[00:11:13.690]In Nebraska, specifically,
[00:11:15.430]we have done some research over the period of one year
[00:11:18.170]to understand the types of spore formers
[00:11:20.970]that could be found at farm level,
[00:11:22.800]and their distribution with the seasons,
[00:11:25.181]to see if there was any correlation.
[00:11:27.724]We visited four farms
[00:11:30.530]and collected two independent milk samples
[00:11:33.270]every month of that year.
[00:11:35.140]This was the first of this kind of study in Nebraska.
[00:11:39.330]So from those samples that were collected
[00:11:41.320]throughout that year,
[00:11:42.690]according to our results,
[00:11:44.560]there was not necessarily a correlation
[00:11:46.465]between spore formers found at the farms
[00:11:49.350]and the seasons of the year.
[00:11:51.080]As you can see, we didn't see any pattern
[00:11:53.975]associated with the months of the year.
[00:11:57.730]Their distribution was variable throughout that year,
[00:12:01.170]without any evident patterns that we could identify.
[00:12:04.435]Also, as we can see in the chart,
[00:12:06.830]the levels of psychrotrophic spore formers,
[00:12:09.240]which is the lightest blue,
[00:12:12.400]were very very low in the pasteurized milk.
[00:12:16.370]We can barely see them on the chart here.
[00:12:19.240]There's a little bit showing in the month of March,
[00:12:21.530]but the levels were quite low.
[00:12:24.420]But non-negligible is we're gonna see in our next slide.
[00:12:27.770]The majority of the spore formers
[00:12:29.290]associated with the pasteurized milk
[00:12:31.180]were either mesophilic or thermophilic spore formers.
[00:12:38.280]So, after we determine the number of spore formers
[00:12:41.340]in the lab, pasteurized milk,
[00:12:42.870]we stored those samples under refrigeration,
[00:12:45.370]and then we then evaluated every week
[00:12:48.240]to see if any of those surviving spores
[00:12:50.383]could grow under refrigeration.
[00:12:53.190]And what we were trying to look for here
[00:12:55.470]is for those psychrotrophic spore formers,
[00:12:58.220]and to see if they were present,
[00:13:00.030]and if they would start to grow
[00:13:02.528]to the point of spoiling those pasteurized milk,
[00:13:06.750]limiting their shelf life.
[00:13:08.580]And as we can see, by 21 days here,
[00:13:13.160]we had about 65% of our samples
[00:13:16.643]showed growth that was higher than 4.3 log CFU per mil,
[00:13:22.676]which is the limit for the PMO standards
[00:13:26.610]for lab pasteurized milk.
[00:13:28.020]So that indicates that the majority of the samples
[00:13:31.010]would not comply with the PMO standards for pasteurized milk
[00:13:35.760]by 21 days.
[00:13:37.670]Additionally, 46% of those samples
[00:13:41.010]had such bacteria growth that they showed visual defects.
[00:13:45.490]So this finds indicate
[00:13:47.180]that even though the levels of psychrotrophic spore formers
[00:13:50.290]in the lab pasteurized milk was very low,
[00:13:53.069]over time they multiplied under refrigeration
[00:13:56.390]and limited the shelf life of the product.
[00:14:00.180]So when we further evaluated the data,
[00:14:03.150]we saw a clear pattern emerging.
[00:14:06.730]A group of samples that did not show spoilage issues.
[00:14:09.870]They were low from beginning to end of those 21 days,
[00:14:14.900]and then we had another group that did show growth
[00:14:17.505]by 21 days of storage.
[00:14:19.973]In attempting to find the reason behind this split,
[00:14:24.470]we decided to look at the source of those samples
[00:14:27.096]that were falling into those two groups.
[00:14:30.460]And we noticed that certain farms
[00:14:32.710]had higher incidence of samples with issues,
[00:14:37.450]while others had less of a problem.
[00:14:40.710]For example, Farm 1 had more samples
[00:14:44.120]that fell into the high spore counts than low spore counts,
[00:14:49.090]while Farm 4 had more samples on the low spore counts
[00:14:55.035]than on the high spore counts.
[00:14:57.330]So it seems that the pattern could be associated more
[00:15:00.730]with the practices at the farms
[00:15:02.830]than with weather, for example,
[00:15:04.980]as we did not see that correlation
[00:15:06.890]throughout the year with the different seasons.
[00:15:09.415]So with the information in mind about the farms,
[00:15:14.170]we moved the research further,
[00:15:16.920]and we decided to start evaluating simple interventions
[00:15:20.690]that could be implemented at the farm level
[00:15:22.740]that would have an impact on milk quality in general,
[00:15:26.180]and more specifically in regards to spore formers.
[00:15:30.593]But we still needed to consider one more factor,
[00:15:33.780]the farmers' willingness to make changes around the farm,
[00:15:36.657]and more importantly, their parlor.
[00:15:39.360]So to better understand the practices used in Nebraska,
[00:15:42.950]and what farmers would be willing to change,
[00:15:45.448]an online survey was created
[00:15:47.770]and distributed to farms in Nebraska
[00:15:49.980]through the Midwest Dairy Association.
[00:15:52.310]This survey contained questions
[00:15:54.350]covering five areas of the dairy farm business.
[00:15:58.580]General management of the herd, milking routine,
[00:16:02.040]environmental conditions at the farm,
[00:16:03.840]sanitation, and their records.
[00:16:06.300]Even though we received
[00:16:07.450]a limited number of replies on this survey,
[00:16:10.420]the results were still helpful to understand the practices
[00:16:13.668]and willingness of farmers to make changes.
[00:16:18.173]What we learned was that farmers
[00:16:21.920]would be willing to change things that were associated,
[00:16:26.927]for example, with their CIP protocols and sanitizers,
[00:16:32.530]and 71% of the respondents would participate in a study,
[00:16:36.392]in 81% would share some records
[00:16:39.470]of somatic cell counts, total plate counts
[00:16:44.820]and lab pasteurized counts,
[00:16:46.460]with researchers on their confidentiality,
[00:16:49.120]so we could better understand what was going on.
[00:16:52.256]Specifically about practices
[00:16:55.080]that they would not be willing to change,
[00:16:58.812]it was highlighted to us
[00:17:01.090]that 80% would not change their bedding,
[00:17:04.240]and 65% would not change their towel method,
[00:17:08.500]which is understandable as these two last areas here
[00:17:12.480]are much related to the management system
[00:17:14.850]that is already implemented in the farm,
[00:17:17.320]and changing them would require
[00:17:19.919]a high capital investment by the farmers.
[00:17:24.870]So with that in mind,
[00:17:26.440]we thought about simple interventions that would be in line
[00:17:32.151]with what farmers would be willing to change.
[00:17:35.360]And we designed an experiment or a project around it.
[00:17:39.470]And that consisted of selecting farms
[00:17:42.350]that were willing to participate in the study,
[00:17:44.910]and then establishing a microbiological baseline
[00:17:48.950]for the raw milk samples coming out of that farm,
[00:17:52.107]and any other relevant environmental samples.
[00:17:55.420]So we would be looking at microbial counts
[00:17:59.140]in raw milk samples
[00:18:00.450]and the environmental samples coming out of that farm
[00:18:03.820]to better understand what was going on
[00:18:06.250]with current practices.
[00:18:08.010]Then we would propose a change,
[00:18:10.120]and we would implement that change,
[00:18:12.257]and let it acclimate for a while
[00:18:15.700]so the employees would be familiar with the practices,
[00:18:20.610]and things would fall in place once again,
[00:18:23.500]and then we would return to the farm
[00:18:25.250]and collect data once again,
[00:18:27.540]and then compare the two sets
[00:18:29.290]to see if a change in those practices
[00:18:32.500]would indeed improve the quality of the milk.
[00:18:39.780]So in the interest of our time here,
[00:18:42.270]I will detail one of the interventions that we implemented,
[00:18:46.190]so you can all understand what went into each of them,
[00:18:50.610]and then I'm gonna share a general result table
[00:18:53.655]that summarizes the results
[00:18:56.110]from all the different interventions at the different farms.
[00:18:59.690]So the first intervention
[00:19:01.190]that we're gonna be looking in detail here
[00:19:04.010]is the one associated with the method used
[00:19:06.310]for cleaning the towels
[00:19:08.090]used for wiping the cow's teat prior to milking.
[00:19:11.690]So for the first eight days that we visited that farm,
[00:19:15.720]we collected samples, for example, clean towels,
[00:19:20.870]used towels, and swabs of the cow's teats,
[00:19:23.990]and then we evaluated them
[00:19:26.270]for the baseline levels of spore formers.
[00:19:29.538]And during this period,
[00:19:31.590]the towels were washed as usual by the farm employees.
[00:19:35.030]Then for about two weeks, the new protocol was implemented
[00:19:38.590]Where bleach was added to their protocol of washing.
[00:19:44.018]After the acclimation period, we then went back to the farm
[00:19:48.122]and samples were collected once again for evaluation
[00:19:52.620]for another period of 8 to 10 days.
[00:19:56.508]When we brought those samples to the laboratory,
[00:19:59.274]we had raw milk samples that were then pasteurized,
[00:20:04.100]either at 80 Celsius degree for 12 minutes,
[00:20:07.860]or 160 Celsius degree for 30 minutes.
[00:20:11.770]After lab pasteurization,
[00:20:13.520]samples were then plated in general media,
[00:20:16.750]followed by incubation for two days
[00:20:19.150]at 32 Celsius degree for mesophilic spore counts,
[00:20:22.640]and 55 Celsius degree for thermophilic spore counts.
[00:20:26.800]The samples that had been lab pasteurized
[00:20:29.110]at a higher temperature
[00:20:30.520]were incubated at 55 Celsius degree
[00:20:33.900]for quantifying the thermoresistant spore counts.
[00:20:38.970]We also treated environmental samples very similarly,
[00:20:42.640]accepted that at the very beginning here,
[00:20:45.140]we had a dilution step.
[00:20:47.760]And like I said, we collected samples
[00:20:50.380]before and after implementing interventions,
[00:20:53.230]and we ran all those samples
[00:20:55.670]through this microbiological analysis,
[00:20:59.370]and then all the data was used for understanding
[00:21:03.245]if the intervention was efficient
[00:21:08.000]in reducing the number of spore formers or not,
[00:21:10.540]through statistical analysis.
[00:21:13.310]So when we look at the results for mesophilic spore counts,
[00:21:18.030]before we have the solid blue bar,
[00:21:21.510]and after we have the striped bars.
[00:21:25.730]We have the results for our intervention
[00:21:28.240]where the sanitizer was used during washing of the towels.
[00:21:33.933]When we look at the bars,
[00:21:36.230]the number of mesophilic spore formers
[00:21:38.380]either remained the same,
[00:21:40.565]and the same letters here means same results,
[00:21:45.030]or they were reduced in some of those environmental samples.
[00:21:48.820]And including the milk as well, they were reduced.
[00:21:52.729]So we could conclude that the mesophilic spore formers
[00:21:57.840]either remained the same
[00:21:59.440]or were reduced in the environmental samples,
[00:22:02.650]and the results that we saw in the milk were quite positive
[00:22:07.396]because they were statistically reduced.
[00:22:12.710]So let's look now at the thermophilic spore counts
[00:22:15.730]and thermoresistant spore counts
[00:22:17.530]associated with this intervention.
[00:22:19.680]If we look at the environmental samples first,
[00:22:22.400]for the most part, those values were significantly reduced.
[00:22:27.380]However, when we look at the milk samples,
[00:22:31.230]we don't quite see that difference.
[00:22:33.180]Like no statistical difference
[00:22:34.541]was observed for those samples.
[00:22:38.750]When we consider the raw milk quality
[00:22:41.790]under this new protocol,
[00:22:44.160]no differences were noted
[00:22:46.020]in any of the major bacterial groups of interest
[00:22:48.950]that we were following along.
[00:22:51.440]We didn't see any changes on total plate count,
[00:22:54.011]Enterobacteriaceae, Coliforms or E-coli.
[00:22:58.700]So the milk quality in general was not affected.
[00:23:02.210]When the shelf life of the product was evaluated,
[00:23:07.040]results showed that it was also not affected
[00:23:10.910]in any way detrimentally,
[00:23:12.950]indicating that the numbers of psychrotrophic spore formers
[00:23:16.380]had also not been necessarily affected by the intervention.
[00:23:23.010]Very similarly, an intervention
[00:23:25.130]associated with the teat sanitizer was implemented.
[00:23:28.900]In this intervention, the teat sanitizer
[00:23:31.170]that originally was an iodine-based dip
[00:23:34.440]was replaced by one that was chlorine-based.
[00:23:37.920]The Neal dip was composed of two parts
[00:23:40.800]that had to be mixed prior to use.
[00:23:43.730]The reason why we proposed the use of a chlorine-based dip
[00:23:47.310]was because information received from our contacts
[00:23:50.520]in the milk powder industry
[00:23:52.185]indicated that milk powder with less iodine levels
[00:23:55.880]was more desirable in international markets.
[00:23:58.530]So we were interested in knowing how a switch
[00:24:01.850]from an iodine-based to a chlorine-based dip
[00:24:05.030]would affect milk quality in general,
[00:24:07.570]and the levels of spore formers.
[00:24:09.565]For this type of intervention,
[00:24:11.377]three brands of chlorine-based sanitizers
[00:24:15.180]were independently test at different farms.
[00:24:18.030]And the same regimen of collecting baseline data,
[00:24:23.710]changing into the intervention,
[00:24:25.570]and then collecting data once again,
[00:24:27.630]was followed for this particular study as well.
[00:24:33.580]We also had an intervention
[00:24:35.110]associated with the clean-in-place system
[00:24:37.250]used in the farm parlor.
[00:24:39.470]In this intervention, the acid and base chemicals
[00:24:43.456]used in CIP system
[00:24:45.450]to clean the milking equipment and pipelines
[00:24:47.980]were complimented by an oxidizer.
[00:24:50.792]This program has been developed by Ecolab
[00:24:54.170]for management of spore formers
[00:24:55.940]in food processing facilities,
[00:24:57.760]and we wanted to see if it would be useful
[00:24:59.910]in a farm environment.
[00:25:01.580]The implementation required an addition of a pump
[00:25:04.650]to the existing system at the farm
[00:25:06.730]where the tests were being done,
[00:25:08.710]and it also required the use of hot water
[00:25:11.240]which was already available.
[00:25:13.340]However, all those requirements
[00:25:15.310]limited the number of farms
[00:25:17.000]where we could try this intervention.
[00:25:21.650]Another intervention associated with the milking parlor
[00:25:24.620]included the replacement of regular microfiber towels
[00:25:28.240]with a different brand described by the manufacturer
[00:25:31.410]as a proton microfiber towel.
[00:25:34.170]According to the manufacturer of the proton towels,
[00:25:36.868]they had been designed to be of higher performance
[00:25:40.280]for cleaning and sanitation of surfaces
[00:25:42.650]in the biomedical industry.
[00:25:44.670]Therefore, the expectation was that perhaps,
[00:25:48.730]they could also help with additional physical removal
[00:25:51.940]of spore formers from cows teats.
[00:25:56.900]And the last intervention that we evaluated
[00:25:59.320]was associated with the bedding material used in the pens.
[00:26:02.900]At the farm where the intervention was applied,
[00:26:05.470]the original protocol for the bedding
[00:26:08.040]consisted of cleaning the sand twice a week.
[00:26:11.710]The top sand was removed from the pens and washed with water
[00:26:16.280]while separating from the solids,
[00:26:18.250]rocks and other materials like feces,
[00:26:21.150]and then it finally was sun dried.
[00:26:22.940]After the sand was dry, it was added to the pens
[00:26:27.110]to refill them as needed.
[00:26:29.232]The new management practice that we evaluated
[00:26:32.283]consisted in removing that top portion
[00:26:35.220]of the used sand as usual,
[00:26:37.640]but completely replacing it
[00:26:39.410]with new clean sand twice a week.
[00:26:42.300]Due to the cost associated with this intervention,
[00:26:44.740]and the fact that its implementation
[00:26:46.296]is dependent upon the availability of sand at the farm,
[00:26:49.760]this was also an intervention limited to just a single farm.
[00:26:55.047]So, this slide gives us an idea of all the interventions
[00:26:59.050]that were applied at the different farms
[00:27:01.590]during the last two to three years here.
[00:27:04.460]And as we can observe,
[00:27:05.924]not all farms allowed us
[00:27:07.991]to apply interventions in all areas,
[00:27:13.311]because of their original management practices.
[00:27:16.430]So for example, if the farm used originally,
[00:27:21.920]disposable towels,
[00:27:23.390]we couldn't test a washing protocol, right?
[00:27:28.360]Similarly, if the bedding of that particular facility
[00:27:33.520]was not sand,
[00:27:34.910]we couldn't test that particular protocol.
[00:27:38.130]So we worked with each farm individually
[00:27:40.809]to maximize which protocols we could apply at their facility
[00:27:48.622]while minimizing disruption of their work
[00:27:53.350]during our interventions.
[00:27:55.061]And we cannot thank enough the farmers
[00:27:58.560]that did embarked with us in this journey.
[00:28:01.300]Without their commitment,
[00:28:02.610]this research would not be possible.
[00:28:04.850]The two interventions that we see here
[00:28:07.270]that are marked in red,
[00:28:08.954]those that I'm pointing out on the slides,
[00:28:11.630]they still need to be carried out,
[00:28:13.460]since our trials were suspended
[00:28:17.010]because of the pandemic that we're living in.
[00:28:20.430]So we still need to go back to the farms
[00:28:22.750]when things hopefully get a little better,
[00:28:25.461]to finalize this research.
[00:28:28.500]So this table summarizes all the results obtained
[00:28:31.640]with all the interventions at the different farms.
[00:28:34.132]The way we can look at this
[00:28:35.790]is that the more green we see,
[00:28:37.680]the more positive outcome that intervention provided,
[00:28:41.370]either by reducing levels of certain types of spore formers,
[00:28:45.370]or reducing total plate count in the raw milk,
[00:28:49.870]or by reducing levels of spore formers in the environment,
[00:28:53.543]or even increasing the shelf life
[00:28:56.160]of the lab pasteurized milk.
[00:28:58.650]So, we still have some interventions to go through,
[00:29:02.790]like I mentioned,
[00:29:04.040]and we still have a lot of work to do
[00:29:06.110]to evaluate the data for all the different interventions.
[00:29:09.670]Our goal was to use the data generated in this research
[00:29:13.770]and combine that with a risk assessment approach
[00:29:20.350]to evaluate how the interventions may affect
[00:29:24.640]the quality of dairy products
[00:29:26.530]that are made with the raw milk represented here.
[00:29:30.210]So the idea is the facts that we're seeing on this table,
[00:29:35.150]if we use that raw milk, then,
[00:29:37.650]to process into dairy products and dry milk powder,
[00:29:43.266]how much can we improve the quality of those products
[00:29:48.260]and tie back to the interventions
[00:29:50.190]that were done at the farm?
[00:29:51.210]So that's a part yet of our future goals
[00:29:54.931]with this research,
[00:29:57.540]to make sure that we can get the most
[00:29:59.926]out of the interventions
[00:30:01.720]that would be applied in the farm level.
[00:30:07.240]So based on the data that we have so far
[00:30:09.890]and the statistical evaluation that we've done so far,
[00:30:13.010]we could say that a towel sanitizing protocol,
[00:30:16.524]the new CIP system, and the sand protocol,
[00:30:22.300]all showed encouraging results.
[00:30:24.741]The data collected using the chlorine-based teat dip
[00:30:29.824]indicated that a replacement of iodine dip
[00:30:34.680]could be made without detrimental consequences
[00:30:37.410]to the milk quality in general,
[00:30:39.640]and related to spore formers.
[00:30:41.280]So if the farmer has a desire
[00:30:43.820]to move from iodine into chlorine,
[00:30:47.440]they may not prove the quality related to spore formers,
[00:30:51.010]but they also will not detrimentally cause
[00:30:54.250]any other issues to their raw milk.
[00:30:56.270]So it's a switch that is feasible.
[00:31:00.040]However, there was one brand that we tested
[00:31:02.510]that didn't quite match up with the previous results.
[00:31:06.890]So once again, those are not conclusive,
[00:31:09.230]because we still need to replicate
[00:31:10.870]some of those interventions at two of the farms.
[00:31:14.450]Much work it's still required
[00:31:16.070]to bring all the data together.
[00:31:17.660]Like I said, we're hoping to use a risk assessment,
[00:31:20.940]a quantitative risk assessment approach
[00:31:23.020]to then make our final conclusions.
[00:31:25.360]And so the next steps that we intend
[00:31:28.830]in following this research
[00:31:30.350]is to finish the interventions
[00:31:32.330]that were missing to confirm those results,
[00:31:34.770]and then apply the data collected
[00:31:36.430]to that quantitative microbial risk assessment
[00:31:39.360]to evaluate the impact of the interventions,
[00:31:43.200]all the way to products
[00:31:45.270]that might be made with the raw milk,
[00:31:47.173]and then create educational tools and other materials
[00:31:51.005]so we can transfer those information to stakeholders
[00:31:55.590]in the form of either videos, flyers, or NebGuides
[00:32:01.620]that we can put it all the information together
[00:32:03.870]to inform farmers and extension educators
[00:32:07.440]of all that we've learned.
[00:32:10.360]So, in addition to the work we've done
[00:32:12.580]to improve the quality throughout the processing chain,
[00:32:15.060]we have also looked at improving
[00:32:17.140]the safety of dairy products.
[00:32:19.430]And under this umbrella
[00:32:21.020]would be the work we've done at farm level
[00:32:23.020]to prevent issues with mycotoxins,
[00:32:25.490]and also the research related
[00:32:27.480]to sanitation of food processing facilities.
[00:32:31.010]At processing facilities, our projects have included
[00:32:33.900]evaluation of cleaning and sanitation procedures
[00:32:37.180]for cleaning tools and PPE,
[00:32:39.722]strategies to reduce condensation issues,
[00:32:42.710]and also evaluation of transmission of Listeria
[00:32:47.780]within the facility.
[00:32:49.109]Today, I will focus more specifically
[00:32:53.130]in the cleaning and sanitation
[00:32:54.850]of personal protective equipment,
[00:32:56.930]and also Listeria transmission within facilities.
[00:33:00.090]And I'll show some of that research here to you.
[00:33:05.220]So, all of our research
[00:33:07.690]related to sanitation and environmental cross-contamination
[00:33:11.030]is focused on Listeria monocytogenes.
[00:33:14.250]This is a ubiquitous foodborne pathogen
[00:33:16.980]that has been implicated in the past decades
[00:33:19.590]as the cause of several foodborne outbreaks.
[00:33:22.220]And this is in some ways,
[00:33:25.090]a result of Listeria monocytogenes
[00:33:27.036]being able to tolerate harsh conditions,
[00:33:31.600]as well as its ability to survive and grow
[00:33:33.880]in different types of foods.
[00:33:36.210]Some of those conditions are listed here.
[00:33:38.330]For example, the organism can grow at low temperatures,
[00:33:41.810]which becomes an issue in refrigerated products
[00:33:44.590]like milk and other dairy novelties.
[00:33:47.500]It can also survive a wide pH range.
[00:33:52.880]It can grow in environments that are anaerobic or aerobic,
[00:33:58.780]can survived in dry foods
[00:34:00.720]with water activity as low as 0.85,
[00:34:04.090]and can tolerate salt concentrations of up to 14%.
[00:34:09.540]So this gives Listeria an upper hand
[00:34:12.490]in causing issues associated with food products.
[00:34:17.820]So no doubt, with all these survival tools,
[00:34:20.607]Listeria has been associated with foodborne outbreaks,
[00:34:24.540]including those associated with dairy products.
[00:34:30.700]So, we've had outbreaks throughout history
[00:34:34.962]since the 1985 Listeriosis outbreak
[00:34:38.110]associated with queso fresco,
[00:34:40.420]all the way to 2019,
[00:34:42.550]there has been 40 confirmed major outbreaks
[00:34:46.024]associated with Listeria monocytogenes
[00:34:48.640]in pasteurized dairy products.
[00:34:50.680]Examples that I wanna bring out here
[00:34:53.128]that has been highlighted in this slide
[00:34:55.890]would be the outbreak in 2010 to 2015,
[00:35:00.140]which was a multi-state outbreak
[00:35:02.430]from Blue Bell ice cream
[00:35:04.320]that caused 10 illnesses and 3 deaths.
[00:35:07.210]Another example that I'm gonna highlight
[00:35:09.430]is a outbreak in Canada in 2016,
[00:35:12.920]where pasteurized chocolate milk
[00:35:15.464]was contaminated in the processing facility,
[00:35:18.370]and then temperature abused,
[00:35:20.004]and this allowed Listeria monocytogenes populations
[00:35:23.550]to reach high levels,
[00:35:24.810]causing 34 illnesses.
[00:35:27.560]When these outbreaks were investigated,
[00:35:30.560]the conclusions were quite similar.
[00:35:32.800]Because pasteurization temperatures
[00:35:34.940]inactivate Listeria monocytogenes,
[00:35:37.470]the pathogen sources were usually cross-contamination,
[00:35:40.997]unsanitary manufacturing conditions,
[00:35:43.910]and poor hygiene practices in the processing environment.
[00:35:47.297]Indeed, the FDA investigations
[00:35:49.810]have used environmental sampling,
[00:35:52.180]any it has confirmed the presence of Listeria monocytogenes
[00:35:56.172]in association with these outbreaks
[00:35:58.210]and equipment present in those facilities.
[00:36:04.240]Historically, Listeria species in Listeria monocytogenes
[00:36:07.999]have been both isolated from a variety of sites
[00:36:11.810]in dairy manufacturing plants.
[00:36:13.810]These bacteria are most frequently found
[00:36:17.250]in moist environment areas
[00:36:18.735]where condensation and water are available.
[00:36:24.507]So this would include food contact surfaces
[00:36:28.000]like cheese forms, working benches and conveyors,
[00:36:32.030]brushes that are used to wash cheese, and gloves.
[00:36:35.303]It can also be found in non-food contact surfaces,
[00:36:39.250]such as drains, floors and coolers.
[00:36:41.950]It's ubiquitous presence
[00:36:44.103]leads to the potential for contamination
[00:36:47.430]of the food processing environment
[00:36:49.610]where occurrence and persistence of Listeria monocytogenes
[00:36:53.150]is frequent.
[00:36:55.092]Once the pathogen has been established
[00:36:57.800]in the processing facility,
[00:36:58.730]it can be easily carried out
[00:37:00.550]through all the environment by personnel,
[00:37:02.910]and quite often, personal protective equipment
[00:37:05.306]may be a vehicle for this.
[00:37:07.627]PPE, such as gloves, aprons and boots
[00:37:10.690]are essential in the food industry.
[00:37:12.720]When they're used properly,
[00:37:14.700]in addition to protect the workers,
[00:37:17.320]it has also been proven to be crucial for product safety.
[00:37:22.015]Generally, workers are well-informed about PPE
[00:37:26.150]and the need to wear gloves
[00:37:27.660]when handling hazardous chemicals or agents
[00:37:30.720]to protect their own hands.
[00:37:32.580]However, they may not be so well informed
[00:37:35.030]about the issues concerning glove use
[00:37:37.510]to avoid cross-contamination.
[00:37:39.880]Even though the FDA advocates
[00:37:42.050]for an appropriate glove, apron and footwear usage
[00:37:45.630]to prevent cross-contamination during processing,
[00:37:48.840]lack of appropriate PPE use
[00:37:52.120]was among inspectors' main observations
[00:37:55.240]in recent Listeria monocytogenes outbreaks.
[00:37:59.430]As a result, we have decided
[00:38:02.120]to evaluate Listeria innocua transmission
[00:38:04.300]from PPE to different surfaces and food products.
[00:38:07.900]Our goal was for the results to then be used
[00:38:10.700]to better inform the dairy industry
[00:38:13.020]to improve training materials,
[00:38:14.880]and to provide quantitative data
[00:38:16.790]for future risk assessment research around this topic.
[00:38:20.660]So to get us there, PPE,
[00:38:22.700]in this case gloves, aprons and boots
[00:38:25.870]were contaminated with Listeria innocua,
[00:38:28.260]either by a spray or an immersion type of inoculation.
[00:38:32.651]Listeria innocua was used as a surrogate
[00:38:35.470]for Listeria monocytogenes
[00:38:37.191]due to biosafety considerations.
[00:38:40.260]The inoculation procedure was done
[00:38:43.890]to achieve a bacterial population of 7 logs CFU
[00:38:48.530]per square inch of that PPE.
[00:38:50.759]And then after inoculation, the PPE was allowed to dry.
[00:38:55.833]The objective of the experiment was to assess
[00:38:58.800]consecutive transfer from that contaminated PPE,
[00:39:03.750]to food contact and non-food contact surfaces.
[00:39:08.090]So we had consecutive touches that were done,
[00:39:11.090]and then the information was collected.
[00:39:14.987]Depending upon the PPE,
[00:39:18.080]different cross-contamination patterns were evaluated.
[00:39:21.489]So we had gloves to food contact surfaces,
[00:39:26.320]apron to food contact surfaces,
[00:39:28.440]and boots to non-food contact surfaces.
[00:39:32.960]So this slide now shows the summary of results,
[00:39:36.252]and they are a average quantification of those transfers
[00:39:40.920]after 50 consecutive touches.
[00:39:43.605]So, we have the transfer of Listeria from the PPE
[00:39:47.065]to all those different surfaces that we were evaluating.
[00:39:52.180]Results indicated that listeria transfer was different
[00:39:55.840]depending upon the PPE and the surface combination.
[00:40:00.010]Higher transfer values were observed
[00:40:02.210]in glove-mediated transfer,
[00:40:05.930]and the levels were over 5 log CFU per square inch
[00:40:10.190]in queso fresco,
[00:40:11.500]and more than 4 logs in cheddar cheese.
[00:40:14.810]The high levels of transfer
[00:40:16.560]observed from gloves to queso fresco
[00:40:18.700]could classify this combination of PPE and surface
[00:40:22.850]as a high risk for cross-contamination
[00:40:25.390]in a dairy environment.
[00:40:27.496]The risk associated with the transfer
[00:40:30.040]from gloves to fresh cheeses
[00:40:32.500]would then justify the need
[00:40:34.427]for more stringent food handling practices
[00:40:37.400]when producing high moisture soft cheeses,
[00:40:40.300]followed then by other low moisture cheeses.
[00:40:43.640]Gloves also mediated transfer of Listeria to cutting boards,
[00:40:48.690]and those were quantified at about
[00:40:50.680]4 log CFU per square inch.
[00:40:53.250]This combination of PPE and surface is also worrisome,
[00:40:57.230]since seeing those cutting boards are food contact surfaces,
[00:41:00.800]and their contamination could lead
[00:41:02.710]to finished product contamination.
[00:41:05.290]When we look at the non-food contact surfaces
[00:41:08.202]and PPE combinations,
[00:41:10.610]a 2.66 log was observed from aprons
[00:41:15.360]to stainless steel coupons,
[00:41:18.100]and 2.621 from boots to dairy tiles.
[00:41:23.319]Based on this results,
[00:41:24.991]these combinations could be classified
[00:41:27.073]as medium to low risk,
[00:41:29.070]since it involves the contact
[00:41:30.740]of two non-food contact surfaces,
[00:41:33.550]and lower bacterial transference.
[00:41:37.820]Since our transmission studies confirmed Listeria transfer
[00:41:41.440]from PPE to product and plant surfaces,
[00:41:45.070]we saw the need to evaluate
[00:41:46.645]effective sanitizing and cleaning procedures
[00:41:49.800]in order to remove Listeria
[00:41:51.453]from personal protective equipment.
[00:41:55.141]For this research, once again,
[00:41:57.600]gloves, aprons and boots were used,
[00:42:00.090]and inoculated either by spray or immersion inoculation,
[00:42:04.450]with a 7 log Listeria innocua population.
[00:42:08.460]The PPE was inoculated using both
[00:42:11.347]a phosphate buffer inoculum, and also a skim milk inoculum
[00:42:16.776]to a study the impact of higher organic matter concentration
[00:42:21.010]on the inactivation of microbial cells
[00:42:23.260]by the chemicals that were under evaluation.
[00:42:26.360]After this, the inoculated PPE was let to dry,
[00:42:30.270]and multiple sanitizing and detergent agents were evaluated.
[00:42:34.810]Three types of sanitizers commonly used in the food industry
[00:42:37.940]were used in this study.
[00:42:39.900]A chlorine-based sanitizer,
[00:42:42.590]a mixture of quaternary ammonia compounds,
[00:42:45.970]and a peroxy acid based agent.
[00:42:50.430]The concentration of the solutions used were determined
[00:42:53.380]depending upon the type of PPE that was treated.
[00:42:56.390]Gloves and aprons had direct contact with food,
[00:42:59.183]so to meet regulatory requirements,
[00:43:01.235]the levels of quaternary ammonia and chlorine
[00:43:06.402]did not exceed 200 PPM.
[00:43:09.970]According to manufacturer instructions,
[00:43:11.774]the level for the peroxyacetic acid
[00:43:14.350]was set at 0.2% for those personal protective equipment.
[00:43:19.340]For the boots,
[00:43:20.173]the concentrations that were used were higher,
[00:43:22.759]because they are notorious for having much organic matter
[00:43:25.940]from processing plant floors associated with them,
[00:43:29.010]which then require a higher concentration of the chemicals
[00:43:32.120]to be effective.
[00:43:33.400]Therefore, quaternary ammonia and chlorine based sanitizer
[00:43:36.930]were used at 400 parts per million.
[00:43:40.670]And the peroxyacetic acid was once again,
[00:43:43.390]the percentage indicated by the manufacturer.
[00:43:49.320]A water rinse was then used as a control
[00:43:52.950]to see the effectiveness
[00:43:54.210]of each of those different chemicals.
[00:43:56.560]A one minute contact time was allowed
[00:43:58.716]for each of those treatments.
[00:44:01.600]In the interest of time,
[00:44:02.900]I'm gonna detail the results for just one PPE,
[00:44:06.110]and then summarize the results for all the other ones.
[00:44:09.030]In this figure, we can observe
[00:44:10.900]a general view of our results.
[00:44:13.148]And when PBS was used as a carrier for listeria,
[00:44:18.630]the peroxyacetic acid was definitely the best sanitizer,
[00:44:23.880]achieving a 4.6 log CFU per square inch reduction.
[00:44:28.464]However, with the same chemical,
[00:44:30.710]only 8.88 log CFU reduction
[00:44:33.760]was observed in the presence of skim milk,
[00:44:36.692]indicating that the organic matter
[00:44:39.510]greatly influenced the ability of that chemical
[00:44:42.650]to eliminate Listeria.
[00:44:44.650]The same trend was observed with gloves and boots,
[00:44:47.940]where the presence of skim milk,
[00:44:49.424]representing the organic matter,
[00:44:51.490]diminished the anti-microbial activity
[00:44:53.580]of the different sanitizers.
[00:44:55.930]It is typically suggested that a 3 log reduction is needed
[00:44:59.510]to target effect inactivation of bacteria.
[00:45:02.496]Since the sanitizers here
[00:45:04.187]could not reduce Listeria by that much
[00:45:06.750]in the presence of skim milk,
[00:45:08.420]we decided that we needed to have
[00:45:11.830]a extensive cleaning protocol
[00:45:13.660]in order to reduce microbial populations
[00:45:16.136]to levels that were acceptable
[00:45:18.781]in the presence of organic matter.
[00:45:21.593]So we pretty much repeated the whole experiment,
[00:45:26.040]but this time we added a cleaner and mechanical action
[00:45:30.800]in hopes to achieve the desired 3 log reduction.
[00:45:34.210]So we inoculated the PPE with Listeria,
[00:45:37.750]and then we added a cleaning protocol
[00:45:40.520]that consisted of a detergent
[00:45:42.915]followed by a water rinse and then a sanitizer.
[00:45:49.173]The cleaning protocol Number 2,
[00:45:51.510]consisted in further improving that one,
[00:45:54.350]by adding a scrubbing step
[00:45:56.387]between the cleaning and the water rinse.
[00:45:59.930]So protocol Number 1
[00:46:01.440]was cleaner, water rinse and then sanitizer,
[00:46:05.070]protocol Number 2 was detergent, scrubbing,
[00:46:09.290]water rinse and sanitizer.
[00:46:12.790]Cleaner Number 1 was a neutral general purpose product
[00:46:17.960]that was used in the experiments,
[00:46:20.090]and we also tested a cleaner Number 2,
[00:46:23.040]which was a chlorinated alkaline cleaner
[00:46:26.460]that helps with soil removal,
[00:46:28.770]and was described by the manufacturer
[00:46:30.820]as a free rinsing cleaner.
[00:46:33.190]As a result, we had four separate combinations of treatments
[00:46:37.375]that were evaluated at this point.
[00:46:39.450]And the efficacy of each was evaluated by quantifying then,
[00:46:43.830]the amount of Listeria by spread plating,
[00:46:46.950]with an overlay that was selective
[00:46:49.060]for our organism of interest
[00:46:51.500]in all of those personal protective equipment.
[00:46:58.000]So here, I'm gonna detail the results for the aprons,
[00:47:02.370]and then we're gonna summarize for all the other PPEs.
[00:47:05.930]In this figure we can observe
[00:47:07.750]that the average Listeria innocua reduction in the aprons
[00:47:12.991]using the four different treatments,
[00:47:16.350]two cleaners with and without scrubbing,
[00:47:20.150]shows that the higher reduction in Listeria
[00:47:24.030]was achieved using the alkaline detergent,
[00:47:28.090]which is the first two bars.
[00:47:30.680]And when the scrubbing step was added,
[00:47:33.730]even the chlorinated detergent
[00:47:35.920]then increase its effect or efficacy.
[00:47:40.754]This results highlight the need
[00:47:42.700]for definitely removing soil prior to sanitizing,
[00:47:46.810]because that's what the cleaner did here.
[00:47:49.610]And also highlight that dependent upon the cleaner
[00:47:53.000]that you choose to use,
[00:47:54.521]a scrubbing step may be necessary as well
[00:47:59.410]to achieve the reductions that are desired.
[00:48:02.409]So one needs to be careful
[00:48:04.250]while establishing their cleaning and sanitizing protocols,
[00:48:07.010]as it may vary with the products that are chosen
[00:48:09.940]for that particular job.
[00:48:11.849]So this table now summarizes all the results obtained
[00:48:15.700]with all the cleaning and sanitizing protocols
[00:48:18.220]that were evaluated
[00:48:19.750]in all the different types of PPEs
[00:48:24.110]when organic matter was present.
[00:48:26.450]The red color that we see
[00:48:28.342]represents a Listeria innocua reduction
[00:48:31.640]of less than 1 log CFU per square inch,
[00:48:34.540]which is an indication that the sanitizer was not effective
[00:48:38.170]in reducing the organisms of interest.
[00:48:40.870]The orange color shows reductions
[00:48:44.209]between 1 and 3 logs,
[00:48:46.910]which again, indicates that using just that sanitizer,
[00:48:51.260]which is the situation described
[00:48:53.180]on the top of the table here,
[00:48:55.090]is not enough to reduce
[00:48:56.920]and inactivate Listeria to safe levels.
[00:49:00.002]Only when the testing protocols
[00:49:02.317]included the alkaline detergent,
[00:49:06.950]or a chlorinated detergent and scrubbing,
[00:49:09.530]it's when we started seeing green on our table here.
[00:49:15.070]And the green indicates a log reduction
[00:49:17.960]that is above 3 logs.
[00:49:22.750]The light green indicates 3 to 5,
[00:49:25.470]and the dark green indicates beyond 5 log reduction.
[00:49:30.010]And it's clear that only those protocols
[00:49:33.380]where scrubbing was included,
[00:49:35.430]we had the highest level,
[00:49:37.180]regardless of the type of PPE
[00:49:39.558]that we were trying to clean and sanitize.
[00:49:43.502]So, when we are trying to choose the protocol
[00:49:47.137]to be used at a facility,
[00:49:49.130]we need to make sure that we have a choice of detergent
[00:49:55.500]and protocols that may include scrubbing
[00:50:00.070]to maximize the reduction of Listeria,
[00:50:03.366]and therefore ensure the safety of that PPE.
[00:50:08.873]From all the studies that we have,
[00:50:12.202]associated with environmental contamination
[00:50:14.630]in dairy facilities,
[00:50:15.930]we demonstrated that Listeria
[00:50:18.165]can be transmitted from PPE to dairy products and surfaces,
[00:50:22.970]even after 50 consecutive touches.
[00:50:26.540]It also highlights the ineffectiveness
[00:50:29.530]of different sanitizers in the presence of organic matter.
[00:50:33.421]The transmission data also showed that
[00:50:36.210]Listeria innocua transfer was different,
[00:50:38.610]depending upon the combination of PPE and surface
[00:50:42.610]that we were evaluating.
[00:50:44.470]Bacterial transfer from PPE
[00:50:46.665]to food contact surfaces and food products
[00:50:50.150]were higher than those observed
[00:50:52.937]between PPE and non-food contact surfaces,
[00:50:57.600]emphasizing the risk associated
[00:50:59.640]with potential cross-contamination in final products.
[00:51:03.486]And lastly, we did observe encouraging results
[00:51:07.091]with an extensive cleaning protocol,
[00:51:10.080]emphasizing the need of scrubbing in cleaning steps
[00:51:13.500]for effective Listeria control and reduction from PPE
[00:51:18.080]in the presence of organic matter.
[00:51:20.909]And before concluding this presentation,
[00:51:23.520]I would like to thank once again, our farmers,
[00:51:25.850]for their commitment and support.
[00:51:27.570]And also we're very thankful for our funders.
[00:51:30.160]The Agricultural Research Division
[00:51:32.100]at University of Nebraska-Lincoln,
[00:51:34.639]DMI and Midwest Dairy Association for grant supports,
[00:51:38.766]and also our appreciation goes
[00:51:42.260]to all the graduate students that over the years
[00:51:45.290]have contributed to the accumulation of this data
[00:51:48.170]and knowledge that I shared here today.
[00:51:50.460]And finally, I thank the organizers of this webinar
[00:51:53.450]for inviting me to participate
[00:51:55.240]and share with you all our findings.
[00:51:57.797]Thank you for your attention,
[00:51:59.830]and if you have any questions about this presentation,
[00:52:02.640]I would be happy to answer them now,
[00:52:05.030]or via email later.

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Improving Quality and Safety of Dairy Products: A Supply Chain Approach

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