Progress 09/01/19 to 08/31/24
Outputs
Target Audience:The target audiences during the reporting period include dairy producers, cooperatives, processors, extension professionals, retailers, scientists, and regulatory agencies who are currently involved or who plan to become involved in the organic dairy industry. We have engaged with our target audience during the reporting period through advisory council meetings, field days, webinars, and extension efforts. Additionally, reports and report guides have been distributed to all participating farmers. Changes/Problems:For Goal 4, only half of the Gouda cheeses have been produced. The remaining half were scheduled to be produced in November; however, this timeline will likely extend through the end of the calendar year. Cheesemakes were delayed due to performance problems with the selected starter cultures and an ongoing graduate student strike. Assuming cheesemakes can be completed by the end of the year, cheeses will age throughout most of Winter term. Final data will be prepared for publication with a goal of submission in March/April 2025. This faced additional complications due to the shutdown and construction schedule of the OSU creamery during the funded period. The cheese vat had to be relocated multiple times throughout the study period and its use prioritized with other research demands. We are confident that all this work will be completed within the next six months and no additional funding is needed. What opportunities for training and professional development has the project provided?During the reporting period we completed 4 outreach events and training sessions targeted towards organic dairy producers and processors, 1 article targeted towards organic dairy farmers, and 1 informational video. The first outreach and training event was the 2024 Marbleseed Organic Farming Conference in La Crosse, Wisconsin in February 2024. As part of their Organic University series, Dr. Nicole Martin and Guy Jodarski and Kevin Jahnke from Organic Valley delivered a day long workshop that focused on the physical, chemical, microbial, and sensorial aspects of raw milk quality, how handling practices impact testing results, and how practices and factors at the farm influence the different raw milk quality parameters. The second outreach event was a webinar hosted by eOrganic, one of the project's collaborators, in August 2024. Dr. Nicole Martin presented on "Factors affecting bacterial spores in organic bulk tank milk" which discussed our results from Goals 1 and 4. This event was recorded, and the recording was distributed to all participants as well as made available through the eOrganic website. For our third outreach event, we attended Penn State's Ag Progress Days for three days in August 2024. Our team engaged with attendees, presented the udder hair removal video created by project staff, and distributed fact sheets on thermoduric bacteria, sporeforming bacteria in milk, and udder singeing. The udder hair removal video was also published on YouTube which was also published on YouTube (https://youtu.be/NT7Sm33K-bQ?si=L2lfN3jw5wLI1eii). Lastly, we held a virtual field day in collaboration with NOFA-NY in August 2024. This field day was focused on "Using udder hair removal to reduce sporeforming bacteria in raw milk," delivered by Dr. Nicole Martin. The virtual field day was recorded and distributed to all participants as well as made available through NOFA-NY's website. In addition to the outreach and training events, we also published an article targeted towards organic dairy farmers in NODPA News in January 2024, had one peer-reviewed scientific journal article accepted, and submitted three others. The paper citations can be found listed above in the "Publications" section of this report. How have the results been disseminated to communities of interest?During the reporting period, the results of this project have been disseminated to communities of interest through 4 outreach events and training sessions targeted towards organic dairy producers and processors, 1 article targeted towards organic dairy farmers, 1 informational video, and 4 scientific papers as described in the "Publications" section as well as in the events described above. Additionally, final reports were distributed to each of the 102 farmers who participated in this first objective. Reports included individual results from each microbial test performed throughout the sampling year as well as the averages of each test from all of the farms in the study as well as averages for the participating farms in their region. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Goal 1 A notable outcome from the analysis of the data collected previously in Goal 1 was the determination that organic dairy producers who had been certified for fewer than 9 years had consistently higher levels of spores in their bulk tank raw milk than producers who had been certified for more than 9 years. We interviewed five producers both virtually and through a survey to determine what challenges they faced when transitioning to organic dairy farming and during their first few years of shipping certified organic milk. All the farmers touched on how difficult it was to find a veterinarian who was familiar with organic practices, and discussed how other farmers in the organic community were the most helpful resources. We hope to use their responses to continue research and extension efforts. Characterization of 4,194 bacterial isolates isolated from organic raw milk, powders, HTST milk, and raw milk to be used for cheesemaking was completed. We observed that Bacillus spp. dominated the aerobic sporeformers isolated from farm raw milk, pasteurized milk, and powders. Nonmetric multi-dimensional scaling showed that aerobic sporeformer populations in organic farm raw milk differ significantly between climate zones at genus, species, and AT levels, indicating there may be climate driven differences in sporeforming bacterial diversity. The anaerobic/facultative anaerobic sporeformers isolated from farm and cheese raw milk samples represented the orders Clostridiales and Bacillales. Evaluation of the gas produced by anaerobic/facultative anaerobic sporeforming bacteria isolates showed that (i) gas production varied significantly between Clostridiales clades and (ii) one Bacillales clade produced gas amounts that were not significantly different from most Clostridiales clades. Overall, our data indicate (i) a substantial diversity of aerobic and anaerobic sporeformers in U.S. organic dairy supplies with predominant genera and species similar between organic and conventional dairy supplies as previously described, (ii) both anaerobic and facultative anaerobic sporeformers found in organic raw milk produce gas, and (iii) climate may impact aerobic sporeformer diversity in farm raw milk. Goal 2 We developed a web-based interface using Shiny app. This webpage contains 4 existing models that can predict dairy spoilage, including milk spoilage due to sporeformers and post-pasteurization contamination, cheese late blowing, and heat resistant sporeformers in dairy powder. With the data generated from the organic dairy farms as a part of this grant, we enable the autofilling of key microbial inputs specific to organic milk once the users select their milk source. This platform can allow the organic dairy producers to assess the risk of spoilage when using organic milk to produce different dairy products and evaluate various intervention strategies that can potentially reduce the spoilage likelihood. For example, if a dairy processor wants to evaluate the impact on shelf for a transition from producing conventional milk to organic milk, using our model with PSC collected from organic milk, the dairy processor can find that, on average, the organic milk will have 26 days of shelf life while the conventional milk will have 22 days of shelf life, in which the shelf life is defined as 50% of milk exceeding the spoilage threshold of 20,000 CFU/mL. Given that organic milk, on average, has slightly higher BAB, MSC, and TSC, the model simulation showed that cheese and powder made from organic milk might lead to more spoilage. Specifically, the semi-hard cheese aged at 13°C and made from organic milk was simulated to have 24.8% of cheese with late blowing defects at day 60 compared to 9.2% for those made from conventional milk. However, these results are only an example use of our model and do not reflect the relative spoilage risk between organic and conventional dairy products as each individual farm and processor will need their own data for drawing conclusions. Goal 3 There are no updates on this goal for the reporting period, but the key takeaways from our past studies include the following 1) hydrogen peroxide was the only effective sanitizer tested, able to achieve a >2 log reduction against all the strains tested on all three different surface materials. Moreover, it can be considered a highly efficient sanitizer against Anoxybacillus, P. peoriae, and B. pumilus, 2) LB is an effective neutralizer with no sporicidal effect for all strains except for B. pumilus, and 3) treatment with 1% LOX and 5% lactose is effective as growth inhibitor against G. stearothermophilus and B. mycoides on rubber surfaces, while no inhibition was observed against the other two strains for the same concentration. This study highlights the potential of hydrogen peroxide, added directly or as a byproduct of lactose oxidation, as an organic-friendly effective sanitizer against relevant dairy spore forming bacteria on common work surfaces. Goal 4 Using the survey and microbiological data collected previously in Goal 1, udder hair removal was identified as a factor of importance for the level of bacterial spores in certified organic bulk tank raw milk. Four organic dairy farms that had not routinely removed udder hair were recruited, and bulk tank samples were collected for 1 week prior to and 1 week after a singeing intervention on all lactating dairy cows. Raw milk samples as well as whole milk powder manufactured from the raw milk collected before and after the intervention were assessed for different groups of dairy relevant bacterial spores. Raw milk samples were evaluated for mesophilic, thermophilic, and psychrotolerant spores as well as butyric acid bacteria. Mesophilic and thermophilic spore concentrations were determined in the whole milk powder. A numerical reduction from pre- to post-intervention was observed in the mean raw milk mesophilic spore count, thermophilic spore count, and butyric acid bacteria most probable number, while a numerical increase was observed in the mean raw milk total bacteria count and psychrotolerant spore most probable number, although none of these changes were significant. The mean mesophilic spore count and thermophilic spore count in whole milk powder manufactured from pre- and post-intervention raw milk was, however, significantly reduced from 2.46 to 1.58 log10 cfu/g and 1.44 to 1.22 log10 cfu/g, respectively. The results of our study indicate that udder hair removal may aid in reducing key populations of spores found in organic raw milk and resulting dairy powders manufactured from that raw milk, although the small sample size in our study likely impacted the significance of our results. Preliminary cheese inoculation studies were performed using C. tyrobutyricum vegetative cells inoculated into pasteurized milk at a higher inoculum level (~3 log CFU/mL) with aging at 13-20°C for up to 12 weeks (84 days). Cheeses were vacuum packaged at the beginning of aging, but packaging expanded to become pressurized during aging. Most cheese wheels were distorted, and the wax casing was often cracked. Computed tomography (CT) scanning images showed holes, cracks, and a single extremely large split were observed in cheese after 5 weeks of aging. Gas also accumulated below the wax causing a separation between the cheese and the wax. Goal 5 During the reporting period we completed 4 outreach events and training sessions targeted towards organic dairy producers and processors, 1 article targeted towards organic dairy farmers, 1 informational video, and 4 scientific papers. The papers can be found in the Publications section and a description of each of these events can be found in the responses below.
Publications
- Type:
Peer Reviewed Journal Articles
Status:
Published
Year Published:
2024
Citation:
Lee, R.T., R.L. Evanowski, H.E. Greenbaum, D.A. Pawloski, M. Wiedmann and N.H. Martin. Troubleshooting high laboratory pasteurization counts in raw milk requires characterization of dominant thermoduric bacteria, which includes non-sporeformers as well as sporeformers. J. Dairy Sci., 107 (2024), pp. 3478-3491
- Type:
Other
Status:
Under Review
Year Published:
2024
Citation:
Lee, R.T., R.L. Weachock, Z.D. Wasserlauf-Pepper, M. Wiedmann and N.H. Martin. Sporeforming bacterial populations from organic raw milk and other dairy products are diverse and appear to differ by climate of origin. J. Dairy Sci.
- Type:
Other
Status:
Under Review
Year Published:
2024
Citation:
Qian, C., R.T. Lee, R.L. Weachock, M. Wiedmann, and N.H. Martin. A machine learning approach reveals that spore levels in organic bulk tank milk are dependent on farm characteristics and meteorological factors. J. Food Prot.
- Type:
Other
Status:
Under Review
Year Published:
2024
Citation:
Wasserlauf-Pepper, Z. R. L. Evanowski, C. Geary, M. Wiedmann, and N.H. Martin. Spore levels in bulk tank organic raw milk and whole milk powder are reduced by udder hair singeing. J. Dairy Sci. Comm
- Type:
Other
Status:
Published
Year Published:
2024
Citation:
Lee, R.T and Nicole Martin. Understanding the Role of Laboratory Pasteurization Count in Organic Dairy Practices. NODPA News 24:1. January 2024, pp. 17-19.
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Progress 09/01/22 to 08/31/23
Outputs
Target Audience:The target audiences during the reporting period include dairy producers, cooperatives, processors, extension professionals, retailers, scientists, and regulatory agencies who are currently involved or who plan to become involved in the organic dairy industry. We have engaged with our target audience during the reporting period through advisory council meetings, webinars, conferences, field days, and extension efforts. Changes/Problems:A notable outcome from the analysis of data collected in Goal 1 was the determination that organic dairy producers who had been certified for less than 9 years had consistently higher levels of spores in their bulk tank raw milk than producers who had been certified for more than 9 years. Of the 28 random forest models conducted, certification year was found in the top variables of importance in 25 models. We hypothesize that this outcome is related to specific conditions encountered by organic dairy farmers in the first several years of becoming certified organic. However, the current study was not designed to assess these conditions, so in addition to the experiments outlined in this report for the next reporting period we will also include a follow-up survey that will be administered to the organic dairy farmers that participated in Goal 1 in order to investigate what could be driving this result. If needed we will also conduct a virtual focus group with a subset of those dairy farmers. What opportunities for training and professional development has the project provided?During the reporting period, the project has provided training and learning opportunities through the events described in Goal 5. How have the results been disseminated to communities of interest?In addition to direct dissemination of results from this study to organic producers and processors, other academic institutions, and related organizations, we disseminated results to communities of interest through three infographics, three outreach events, two posters presented at the American Dairy Science Association annual meeting, one peer-reviewed publication in review, and two additional peer reviewed publications are in preparation. What do you plan to do during the next reporting period to accomplish the goals?Goal 1 In the next reporting period, characterization of the sporeforming bacterial isolates collected from raw milk samples will be completed and used to facilitate progress on Goals 2 and 4. Two peer reviewed publications that are currently in progress will be submitted to the Journal of Dairy Science. Goal 2 Using the data collected in Goal 1, our baseline Monte Carlo simulations will be updated with organic dairy-specific sporeforming bacterial subtypes and the Monte Carlo simulation for organic dairy powder will be completed. Goal 3 Based on the previous results an additional experiment will be implemented in the next reporting period focused on the development of an antimicrobial tool by combining the effect of LOX with other natural antimicrobials for a more efficient and target-directed growth inhibition effect. Goal 4 Using the survey and microbiological data collected in Goal 1, intervention trials on-farm and in processing facilities will begin in the next reporting period. To evaluate the impact of the intervention we will manufacture processed dairy products, including fluid milk, cheese, and dairy powders at pilot facilities. Spore levels, and shelf-life results when appropriate, will be used to further enhance the Monte Carlo models developed in Goal 2. Goal 5 Project staff will work with project collaborators NOFA-NY and RODALE Institute to complete two additional field-days focusing on disseminating results of the project to communities of interest. A compilation of online training modules will be completed and disseminated through eOrganic and through collaborator pathways. We will also conduct an Organic University workshop at the annual Marbleseed conference in February 2024 and are preparing a farmer focused article on thermoduric bacteria in organic raw milk that is planned to be published in the Northeast Organic Dairy Producers Alliance newsletter.
Impacts
What was accomplished under these goals?
Goal 1 During the previous reporting period, a total of 4,434 isolates were collected from HTST milk (n=156), powders (n=19), cheese raw milk (n=88), farm raw milk (n=4,171). Of the 4,171 farm raw milk isolates, 3,088 were aerobic sporeformers and 1,083 were butyric acid bacteria. Characterization of isolates has occurred during the current reporting period and is ongoing with 2,995 isolates successfully sequenced. The aerobic sporeforming bacteria isolated from HTST milk, powders, and farm raw milk were largely represented by Bacillus and Paenibacillus and the anaerobic sporeforming bacteria isolated from cheese raw milk and farm raw milk were largely represented by Clostridium and Bacillus. Analysis of spore count data collected from 102 certified organic dairy farms across the US along with farm practices survey data and meteorological data were analyzed using a random forest model with 1,000 trees trained to predict spore counts in organic raw milk. A total of 7 data subsets were assessed, including i) all available data, ii) 2 data sets stratified by whether the farm used a parlor or no parlor for milking, iii) 2 data sets stratified by whether the associated raw milk sample was collected when lactating cows had been on pasture or not on pasture, and iv) 2 data sets stratified by the number of years the farm had been certified organic (e.g., ≤9 years or >9 years). High level results from these analyses indicate that weather conditions (e.g., humidity, precipitation, etc.) are variables of importance to spore levels in organic raw milk, especially under certain conditions. For example, when lactating cows are on pasture, the top three variables of importance for anaerobic butyric acid bacterial spores are weather related, whereas when lactating cows are housed, weather variables do not show up in the top 15 variables of importance. Further, results show that udder hair removal and number of years certified organic consistently show up in the top 15 variables of importance for all spore types and regardless of data stratification. These results are important for implementing on-farm interventions in the remaining reporting period. Goal 2 Base Monte Carlo simulation development for organic fluid milk and organic cheese was completed during the reporting period, using spore distribution data collected in Goal 1. Final model completion will occur in the next reporting period as these models may need to be modified to reflect parameters specific to spore allelic types in organic raw milk. Identification and allelic type assignment on ~4,100 raw milk sporeformer isolates will be used to update the models when completed in the next reporting period. Further, our group has completed the development of an online, user-friendly tool that can be utilized by organic dairy industry stakeholders in the future to improve organic dairy product quality. The final Monte Carlo simulation for organic dairy powders is in development and will be completed in the next reporting period. Goal 3 For this aim, four treatments for each sanitizer and bacterial strain were carried out. The treatments consisted of water (control) or sanitizer inoculated with the bacterial strain, in which LB was added before or after incubation at the optimal growth temperature. Results of the first two parts of the study indicated that only hydrogen peroxide was an effective sanitizer, able to achieve a >2 log reduction against all the strains tested on all three different surface materials. Moreover, it can be considered a highly efficient sanitizer against Anoxybacillus, P. peoriae, and B. pumilus. LB proved to be an effective neutralizer with no sporicidal effect for all strains except for B. pumilus. The third part of the study evaluated the effect of the addition of lactose oxidase (LOX) together with lactose to release hydrogen peroxide as a byproduct of the oxidation of lactose to lactobionic acid. In these tests the same procedure was carried out with the simultaneous addition of LOX and lactose in a concentration necessary to achieve 0.5-1% LOX and 5% lactose, as the test sanitizer. Inhibition against four of the most resistant strains tested in the first part of the study was assessed: G. stearothermophilus, B. mycoides, B. licheniformis, and B. pumilus. Results indicate that a treatment with 1% LOX and 5% lactose is effective as growth inhibitor against G. stearothermophilus and B. mycoides on rubber surfaces, while no inhibition was observed against the other two strains for the same concentration. Altogether, this study highlights the potential of hydrogen peroxide, added directly or as a byproduct of lactose oxidation, as an organic-friendly effective sanitizer against relevant dairy spore forming bacteria on common work surfaces. Based on the previous results a new study designed over the last few months contemplates the development of an antimicrobial tool by combining the effect of LOX with other natural antimicrobials for a more efficient and target-directed growth inhibition effect. Goal 4 Based on results from data analysis conducted in Goal 1, we have identified an intervention target for spore levels in organic bulk tank raw milk, namely the removal of udder hair. Of the 28 random forest models conducted, udder hair removal through clipping or flaming was found in the top variables of importance in 21 of the models. Udder hair removal is further an appropriate target for implementation trials as this is a simple, low-cost intervention that can be adopted across organic dairy producers, regardless of location or size, with little investment. An evaluation of this intervention will be conducted in the next reporting period. Goal 5 During the reporting period we completed three outreach events and trainings targeted toward organic dairy producers and processors. The first event was held as part of the winter conference for project collaborator, NOFA-NY in January 2023. The presentation was delivered by project team member, Dr. Nicole Martin and was entitled "Bacterial Populations in Organic Raw Milk Impacting Finished Product Quality" with a focus on the implications of sporeforming bacteria in organic dairy systems, and practices of importance for transmission of spores into organic bulk tank raw milk. The second event was a field day conducted by Rodale Institute in July 2023. Our team engaged with attendees, presented two posters on the project, and distributed infographics on thermoduric bacteria and sporeforming bacteria in organic raw milk. Lastly, we held a virtual field day in collaboration with NOFA-NY in November 2023. This field day was focused on "Understanding thermoduric bacteria in organic raw milk and the laboratory pasteurization count", delivered by Dr. Nicole Martin. The virtual field day was recorded and the recording was distributed to participants as well as made available through the NOFA-NY website: https://nofany.org/resources/dairy-resources/. In addition to the outreach events described here, our team submitted a proposal to conduct an Organic University workshop at the upcoming 2024 Marbleseed conference that will be held in La Crosse, WI in February. This proposal was accepted and team members are collaborating with Organic Valley staff to develop this workshop.
Publications
- Type:
Journal Articles
Status:
Under Review
Year Published:
2023
Citation:
Lee, R.T., R.L. Evanowski, H.E., Greenbaum, D.A. Pawloski, M. Wiedmann and N.H. Martin. Troubleshooting high laboratory pasteurization counts in raw milk requires characterization of dominant thermoduric bacteria, which includes non-sporeformers as well as sporeformers. J. Dairy Sci. In Review.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2023
Citation:
Bacteria enumerated by laboratory pasteurization count in organic raw milk are predominantly Gram-positive sporeformers and Gram-positive cocci. R. Lee*1, R. Evanowski 1, H. Greenbaum 2, M. Wiedmann 1, and N. Martin 1, 1 Cornell University, Ithaca, NY, 2 University of Southern California, Los Angeles, CA.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2023
Citation:
Machine learning models suggest farm management practices and weather conditions only account for a small proportion of variance in spore levels of organic raw milk. C. Qian*, R. T. Lee, R. Evanowski, M. Wiedmann, and N. H. Martin, Cornell University, Ithaca, NY.
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Progress 09/01/21 to 08/31/22
Outputs
Target Audience:The target audiences during the reporting period include dairy producers, cooperatives, processors, extension professionals, retailers, scientists and regulatory agencies who are currently involved or who plan to become involved in the organic dairy industry. We have engaged with our target audience during the reporting period through advisory council meetings, webinars, workshops, research and extension efforts. Changes/Problems:In 2022, several organic producers enrolled in the Goal 1 study described here, expressed concern regarding the results of their routine (non-project related) Lab Pasteurization Count (LPC) and how it would affect their status in their cooperative. The LPC is often used as a quality marker for raw milk prior to pasteurization at the processor level, and a proxy for spore concentration. The LPC test consists of pasteurizing the raw milk (63oC for 30 minutes) followed by plating on Standard Plate Count Agar and incubating at 32oC for 48 hours. This test is often required by farm cooperatives and/or fluid milk processors to quantify the quality of raw milk, with quality cutoffs ranging between ~200-300 CFU/ml. This led the project team to conduct a study on a subset of the raw milk samples from Goal 1 to determine the concentration and characterization of bacteria recovered from LPCs in organic milk and their relationship with spore levels in organic raw milk. An initial proof of concept experiment was conducted to determine if freezing raw milk samples prior to LPC testing impacted the total bacteria concentration as well as the types of bacteria recovered after pasteurization. Project members collected 15 duplicate samples of raw milk, froze one replicate for 24h at -20°C, and conducted an LPC on the fresh versus frozen samples. In addition to LPC results, 150 bacterial isolates were characterized at the Genus level by 16S sequencing. Mean log concentrations (CFU/ml) for fresh and frozen samples were 1.805 and 1.853, respectively. There was no significant difference (p = 0.78) between the two sets of samples. Characterization results also did not differ between the fresh and frozen samples. Isolates from fresh raw milk LPC tests (n=77) were 45% Bacillus, 17% Brachybacterium, 19% Microbacterium, 8% Streptococcus, and 10% other while isolates from the matched frozen milk LPC tests (n=73) were 47% Bacillus, 16% Brachybacterium, 18% Microbacterium, 8% Streptococcus, and 11% other. After comparing the results, the team moved forward with using frozen milk samples in the study. The LPC concentration and population characterization of raw milk samples (n=93) from one round of sampling from the organic milk producers enrolled in the raw milk study were determined. The mean concentration (log CFU/ml) for the samples was 1.28 with a standard deviation of 0.84. Unique surface colony morphologies and a representative number (up to 5) of sub-surface colonies were isolated and characterized using 16S sequencing. A total of 372 isolates were identified at the family level, with the highest proportion of isolates representing the family Bacillaceae (36%), followed by Dermabacteraceae (14%), Micrococcaceae (18%), Streptococcaceae (10%), Microbacteriaceae (9%), and other (13%). The addition of these experiments to the planned goals of this study will provide key knowledge to organic dairy stakeholders including producers, cooperatives, processors and others. What opportunities for training and professional development has the project provided?During the reporting period, the project has provided training and learning opportunities through the fluid milk processor module and the producer workshop described in Goal 5. The modules and presentations from the workshop are available on the project website. How have the results been disseminated to communities of interest?Farmers who provided samples for Goal 1 were provided preliminary reports with results from tests on their raw milk. In the next reporting period, we will provide them detailed results comparing the data collected from all 102 farms in the study. What do you plan to do during the next reporting period to accomplish the goals?Goal 1 In the next reporting period, characterization of the sporeforming bacterial isolates collected from raw milk samples will be completed and used to facilitate progress on Goals 2 and 4. Analysis of farm survey data along with microbiological data will be completed to identify appropriate intervention strategies for Goal 4. Goal 2 Using the data collected in Goal 1, our baseline Monte Carlo simulations will be updated with organic dairy-specific sporeforming bacterial concentrations and subtypes. Goal 3 Further studies in the next reporting period will be focused on testing the sanitizing effectiveness of lactose oxidase combined with lactose on the same strains and surface materials utilized in the current reporting period. Goal 4 Using the survey and microbiological data collected in Goal 1, intervention trials on-farm and in processing facilities will begin in the next reporting period. Goal 5 Project staff will work with project collaborators NOFA-NY and RODALE Institute to plan and execute field-days focusing on disseminating results of the project to date.
Impacts
What was accomplished under these goals?
Goal 1 Sample collection and testing of organic finished products was completed during the reporting period. Two additional organic dairy farms were recruited to participate in Goal 1, for a total of 102 farms. Participating farms were located in PA (n=28), NY (n=26), CA (n=17), OR (n=5), CO (n=5), WA (n=7), WI (n=5), ID (4), VT (n=3), IA (n=1) and MN (n=1). During the 2021-2022 reporting period, a total of 563 raw milk samples were collected, and a total of 2,121 microbiological tests performed (Aerobic Plate Count (APC): n=536, Mesophilic Spore Count (MSC): n=528, Thermophilic Spore Count (TSC): n=559, Psychrotolerant Spore Count - Most Probable Number (PSC-MPN): n=536, Butyric Acid Bacteria - Most Probable Number (BAB-MPN): n=498). Inconsistencies in test numbers are a result of lab errors and insufficient volumes of milk for all testing procedures. From those tests a total of 4,108 sporeforming bacterial isolates were collected and saved for characterization in the next reporting period. Average sporeformer concentrations (log CFU/ml) for organic raw milk versus for conventional raw milk from previous studies were: MSC, 0.78 (organic) vs 0.26 (conventional); TSC, 0.44 (organic) vs 0.26 (conventional); PSC-MPN, -1.5 (organic) vs -0.72 (conventional); BAB-MPN, 2.17 (organic) vs 1.7 (conventional) Producers completed surveys for each raw milk sample collected; the first survey asked farmers questions about their farm, housing style, milking parlor, feed, etc. Each subsequent survey was a shorter version of the first survey to understand any seasonal changes made on the farm. Results from these surveys will be analyzed in the next reporting period to determine associations between these practices and the microbiological data collected. Goal 2 No progress on during this reporting period Goal 3 The lactoperoxidase system (LPS) is a natural antimicrobial system present in milk. LPS is activated in the presence of H2O2, which is produced during the oxidation of lactose to lactobionic acid by lactose oxidase (LO). The application of LO to improve the efficacy of the LPS and inhibit microbial growth is an approach that can be used to enhance the shelf life of dairy products. Previous research has shown that lactose oxidase can effectively control organisms such asPseudomonasspp.,Listeria monocytogenes, molds, and yeast. However, it was still unknown if this antimicrobial system would also be effective against spore formers. The aim of this work was to evaluate the antimicrobial effect of LO in the LPS against 28 strains of frequent dairy spore formers isolated for this project from organic dairy products and facilities, and to determine the effective concentration for growth inhibition. For this aim, an overlay inhibition assay was performed. LO was applied in different concentrations (0, 0.1, 1, and 10 g/L) to Brain Heart Infusion and Reinforced Clostridial Media agar containing 2.5% wt/wt lactose, added to the media before sterilization. Plates were then overlaid with inoculated agar and incubated at optimal growth temperatures. The average radius of the inhibition zone for each concentration and strain was calculated and differences between the control and the different LO concentrations were analyzed using one-way ANOVA (P< 0.05). All experiments were performed in biological triplicates. Results indicated that 15 out of 28 strains were inhibited by the lowest LO concentration (0.1 g/L), 10 additional strains showed inhibition at 1 g/L, and the 3 remaining strains were inhibited at the highest LO concentration of 10 g/L. This latter group was composed of bacteria from the genusBacillusspeciessubtilis,paralicheniformis, andgibsonii, which were the most resistant strains, inhibited only by the highest LO concentration. In conclusion, LO proved effective as a growth inhibitor of dairy spore formers and can contribute to enhance the shelf life of milk and other organic dairy products, when added in early production stages. Further studies will focus on testing the effectiveness of the addition of this enzyme directly to dairy products. Effect of alternative sanitizers compatible with organic production against dairy spore formers on common work surfaces - The use of chlorine-based sanitizers in organic dairy production is limited by maximum labelled rates, and these rates are normally insufficient to address the growth of dairy spore formers. Therefore, there is a need to identify alternative sanitizers, such as organic acids and enzymes, that would be effective as natural antimicrobials for the disinfection of dairy processing surfaces. The aim of this study is to prove the effectiveness of hydrogen peroxide, phosphoric acid and Oxysan® (a commercial sanitizer containing hydrogen peroxide, peracetic acid, and acetic acid) as alternative sanitizers against dairy spore formers on common work surfaces. The sanitizers were tested according to the AOAC Method 2008.05, which simulates three different methods of bacterial removal and assesses the bacterial load after each. Chemical concentrations and exposure times were applied as recommended by their manufacturers on PVC, food grade stainless steel, and rubber coupons. Seven aerobic spore-forming strains were selected based on their rate of occurrence in and relevance to dairy processing facilities. According to the official method, a sanitizer must achieve a microbial load reduction of at least two logarithmic units to be considered effective. Results indicate that only hydrogen peroxide was able to achieve such a reduction against all the strains tested and on all three different surface materials. Based on these results and on the results obtainedin vitrofor lactose oxidase, further studies are currently being conducted to test the sanitizing effectiveness of lactose oxidase combined with lactose on the same strains and surface materials Goal 4 No progress on during this reporting period. Goal 5 In December 2021 the project team held an organic producer focused workshop, "Managing Organic Milk Quality on the Farm" which consisted of 2 online modules and a live virtual workshop with 5 guest speakers.Over 100 participants attended the live virtualworkshop, with producers from 28 states and Puerto Rico.Individuals who both attended the live presentation and completed both online modules were given a certificate of completion. The online modules focused on raw milk quality parameters that impact the shelf-life of pasteurized fluid milk and on the factors that affect these parameters at the farm level. The first 50 participants who signed up for the course were provided a sensory defect kit to accompany the online modules. These kits provided participants with a more complete understanding of how certain farm practices can impact finished product quality. The live virtual workshop included 5 presentations that built off the topics discussed in the pre-workshop modules. Presenters were Dr. Paula Ospina, Lechear, Dr. Ernest Hovingh, Pennsylvania State University, Dr. Blake Nguyem, Cornell University, Dr. Valeria Alanis, Universidad Nacional Autonoma de Mexico, and Dr. Paul Virkler, Cornell University. Each hour-long presentation focused on specific farm management practices such as teat and udder health, mastitis, environment and housing, bedding, and milking system management. In March 2022, the project team added a module on organic systems and regulations to an existing fluid milk workshop provided by the Cornell University Dairy Foods Extension. This hybrid online and live virtual course is offered yearly by Cornell and targets fluid milk processors both within and outside of NY. The workshop covers a wide range of topics, all aiming to inform processors on improving the quality and safety of their final products. There are graded evaluations throughout this course and participants who finish with a passing grade are given a Dairy Foods Certificate in Fluid Milk.
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Progress 09/01/20 to 08/31/21
Outputs
Target Audience:The target audiences during the reporting period include dairy producers, cooperative, processors, extension professionals, retailers, scientists and regulatory agencies who are currently involved or who plan to become involved in the organic dairy industry. We have engaged with our target audience during the reporting period through advisory council meetings, webinars, project participant recruitment and extension efforts. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?During the reporting period the project has provided training and learning opportunities through the Dairy Systems Summit as well as through an eOrganic webinar as described above. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?Goal 1 In the next reporting period we plan to complete the baseline raw milk sampling and survey data collection from the 100 organic dairy farms enrolled in the study. We will complete characterization of the sporeforming bacterial isolates collected from these samples to inform the subsequent experimental implementation for Goals 2, 3 and 4, as well as the education and outreach in Goal 5. Goal 2 Using the data collected in Goal 1, our baseline Monte Carlo simulations developed and refined in the current reporting period will be updated with organic dairy specific sporeforming bacterial concentrations and subtypes. Goal 3 Our work with LOX will continue into the next reporting period where we will begin to test the efficacy of LOX to control outgrowth of sporeforming bacteria in organic dairy products including fluid milk, powder and cheese. Goal 4 Microbiological and survey data collected as part of Goal 1 will be analyzed in the next reporting period to determine appropriate targets for intervention trials on-farm and in processing facilities. Goal 5 Project staff will implement producer and processor focused workshops on organic raw milk and finished dairy product quality in the next reporting period. This will include production focused, in-person, hands-on training programming in conjunction with NOFA-NY and RODALE Institute field-days. Workshops focused on improving the quality of organic finished dairy products will be offered during the next reporting period in conjunction with current Cornell Dairy Foods Extension workshops focused on fluid milk, dairy powders and cheese.
Impacts
What was accomplished under these goals?
Goal 1 Sample collection and testing of organic finished products was completed during the reporting period. A total of 37 LTLT/HTST fluid milk samples, 11 powder samples, 10 raw milk samples from organic cheesemakers were collected from organic manufacturers. A total of 100 organic dairy farms were recruited to participate in Goal 1. Farms are located in PA (n=28), NY (n=26), CA (n=17), OR (n=5), CO (n=5), WA (n=5), WI (n=5), ID (4), VT (n=3), IA (n=1) and MN (n=1). During the reporting period a total of 168 raw milk samples have been collected, and a total of ~1,008 microbiological tests performed. From those tests we have collected ~1,625 sporeforming bacterial isolates for characterization. Goal 2 Project staff have finalized a baseline cheese Monte Carlo simulation model that will be used to predict spoilage of semi-hard and hard aged organic cheeses once the baseline sporeformer data is complete. Additionally, project staff have made improvements to the baseline fluid milk Monte Carlo simulation model that will be used to predict spoilage of organic fluid milk. Project staff have additionally developed a beta version of the online interface for use of the predictive Monte Carlo simulations by organic dairy stakeholders. Goal 3 PD Alcaine has completed diffusion assays on sporeforming bacterial isolates of concern to the organic dairy industry to test the effectiveness of Lactose Oxidase (LOX) as a novel intervention for sporeforming bacteria in organic dairy products. A total of 28 sporeforming bacterial isolates were evaluated at 4 LOX concentrations, with varying effectiveness based on strain. Goal 4 No progress on during this reporting period. Goal 5 With feedback from our Advisory Council, we have developed a hybrid workshop targeted toward organic dairy producers and stakeholders. The workshop will consist of a 2h online module with interactive components followed by a half-day live virtual workshop. Content will be focused on raw milk quality parameters that influence organic dairy food quality and farm management practices for controlling these parameters, with a focus on sporeforming bacteria. The live virtual workshop is scheduled for December 16, 2021.
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Progress 09/01/19 to 08/31/20
Outputs
Target Audience:The target audiences during the reporting period include dairy producers, processors, extension professionals, retailers, scientists and consumers who are currently involved or who plan to become involved in the organic dairy industry. This project will not only define the scope of sporeformer contamination levels, population and resulting spoilage, but will provide key guidance and knowledge and technology transfer outreach to industry stakeholders. Specifically, with the knowledge gained and tools developed from this project, our team will be able to train the organic dairy industry on approaches to reduce spoilage by sporeforming bacteria, extend shelf-life to access new distribution channels and take advantage of export opportunities. During this reporting period we have engaged with organic dairy producers, processors, retailers, extension professionals and academic experts. Changes/Problems:At the beginning of the reporting period our laboratory and those of our co-PDs were shut down due to the COVID-19 pandemic. Due to these closures and ongoing travel restrictions at our individual institutions as well as implemented by our State and local governments, our project timeline has been pushed back. No changes have been made to the overall project scope due to these timeline delays. What opportunities for training and professional development has the project provided?Our team has planned a system wide organic dairy summit that addresses opportunities and challenges in the organic dairy industry. Speakers include organic dairy producers, extension and training agents, processors, retailers and academia. This event will be held on December 8, 2020 and has been widely distributed to organic dairy stakeholders. Further, our team has developed three initial educational videos on the challenges that sporeforming bacteria present to the dairy industry and on the project funded here. We continue to work closely with our co-PDs and collaborators to promote these events and educational materials to a broad range of organic dairy stakeholders. How have the results been disseminated to communities of interest?Baseline spore testing results from individual processors have been reported directly back to the key personnel from those companies. In addition, our team has developed extension materials related to sporeforming bacteria and the project funded here, as well as advertising for our organic dairy systems summit (to be held on December 8, 2020) via our project website and existing mailing lists of project personnel, collaborators and advisory council members. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period we will continue to collect organic finished product samples to establish a sporeformer baseline for organic fluid milk, cheese and powder. Bacterial sporeformer isolates will continue to be collected and characterized from these finished product samples. Our team will begin sampling of raw bulk tank milk with a revised protocol in order to maintain social distancing and current public health recommendations. Progress will continue on Objective 3 to test novel solutions to reduce spores in the organic dairy system. Finally, we will continue to development of extension and training materials targeted toward the organic dairy industry (Objective 5) along with disseminating project information to key target audiences through scheduled webinars and task-force meetings.
Impacts
What was accomplished under these goals?
During the reporting period major activities completed include; i) recruitment of organic fluid milk, cheese and dairy powder processors as well as organic dairy producers (Goal 1); ii) initiation of spore baseline testing in organic finished products (Goal 1); iii) Development of a management practices survey targeted toward organic dairy producer to be administered during each raw milk sampling time point (Goal 1); iv) Development of extension materials ranging from project flyers to educational videos (Goal 5); v) Implementation of an in-person kick-off meeting between project PDs and project advisory council in February 2020; vi) Planning of a system wide organic dairy summit to be held in December 2020 (Goal 5); vii) Development of a project website (Goal 5), and; viii) Initiation of experiments to identifynew and existing sporeformer interventions (Goal 3).
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