Our Study

Presentation Integrated Farm (ICLF)/Backyard Farm (BF) Advantages of BF/ICLF Systems Risks associated with ICLF/BF Foodborne illness in the US Objectives of the Study Procedures and Findings Salmonella Enterica (SE) Contamination Shiga-toxin producing E. coli (STEC) Contamination Soil Health and Amendments Skin Microflora of ICLF Workers Animal Waste Effects of Berry Pomace Extract Conclusion and Future Direction Acknowledgements

Presentation



Integrated Farm (ICLF)/Backyard Farm (BF)

The traditional Backyard Farm (BF) and Integrated Crop-Livestock Farm (ICLF) are major contributors to organic food products, particularly products sold in farmers markets (>10,000 in the US). Throughout the US, 144,530 farms sold >$1.5 billion in fresh edible agricultural products directly to consumers

First picture of iclf Second picture of iclf Third picture of iclf
Picture of a typical ICLF
Figure 1. Typical ICLF/BF system

Advantages of BF/ICLF Systems

  • Integrated and sustainable system
  • Increase crop yields and biological activity
  • Intensify land use and improve profits
  • Can help reduce poverty and malnutrition locally
  • Recycling by feeding root crops to animals and animal waste for soil fertility
  • ICLFs use excreta to produce biogas and energy
  • Trend is growing faster in many states of the US, including MD

Risks associated with ICLF/BF

  • Higher mortality of animal
  • No alternatives for growth promoters/therapeutics
  • Often lacking proper planning and landscaping
  • Pest, rodent and wild-bird infiltration
  • Lacking training opportunity and research data
  • Insufficient support and/or regulation
  • Higher risk of bio-security
  • Concern for food safety/cross-contamination
Advantages of BF/ICLF systems
Figure 2. Advantages of BF/ICLF systems

Foodborne illness in the US

Each year, 1 out of 6 Americans gets sick from foodborne disease and >3,000 die as a result. Reducing foodborne illness by just 10% would keep 5 million people a year from getting sick. Economic loss of foodborne illness in US comes in around $77 billion annually. A single fatal case of foodborne infection leads to cost of life as well as $7 million. An outbreak or a single recall can push a company out of business.

Many types of food cause foodborne illness

All types of food including produce, fruits, poultry, eggs, beef, pork, dairy products are responsible foodborne illness. Animal products directly cause >60% of the cases of foodborne illness. Farm animals are also involved in produce-borne infection.

List of multistate foodborne bacterial outbreaks (Reported by CDC, 2023)
Figure 3. List of multistate foodborne bacterial outbreaks (Reported by CDC, 2023)
Image from CDC 2020 report
Figure 4. CDC report, 2020

Objectives of the Study

Objective-1: Determine the sources, survival and persistence ability in the various components of the ICLF environment and contamination pathways of SE and STEC.
Objective-2: Develop practical means to control SE and STEC in ICLF environment and eliminate their survival on harvested fresh produce by developing and using novel farm-friendly manure composting methods and natural antimicrobial sanitizers and wash aids.
Objective-3: Disseminate outcomes of the project and measures for controlling fresh produce contamination through on-farm practices and post-harvest processing to diverse stakeholders.


Procedures and Findings

Approaches used in this study
Figure 5. Approaches used in this study
Number of sample collected and their sources
Figure 6. Number of sample collected and their sources

Salmonella Enterica (SE) Contamination

PCR primers used to confirm SE
Figure 7. PCR primers used to confirm SE
SE across all collected samples
Figure 8. SE across all collected samples
Prevalence of SE in farm-level and post harvest
Figure 9. Prevalence of SE in farm-level and post harvest
SE serovars by pre-/post-harvest levels
Figure 10. SE serovars by pre-/post-harvest levels
Antibiotic resistance phenotypes of SE
Figure 11. Antibiotic resistance phenotypes of SE
Antibiotic resistance pattern of SE
Figure 12. Antibiotic resistance pattern of SE

Shiga-toxin producing E. coli (STEC) Contamination

PCR primers used to confirm STEC
Figure 13. PCR primers used to confirm STEC
Prevalence of STEC
Figure 14. Prevalence of STEC
Antibiotic resistance phenotypes of STEC
Figure 15. Antibiotic resistance phenotypes of STEC
Antibiotic resistance phenotypes of STEC
Figure 16. Antibiotic resistance phenotypes of STEC

Soil Health and Amendments

Soil health before and after adding compost
Figure 17. Soil health before and after adding compost
Soil properties
Figure 18. Soil properties

Biological Amendment of Soil and Precautions

  • Increase fertility, organic matter/humas and other accompanying properties
  • ICLFs use manure/compost to improve soil
  • Important for ICLFs to develop proper manure/composting management practices
  • Improper management could allow survival of pathogenic organisms which could be transferred to soil and then produce
Manure stockpile
Figure 19. Manure stockpile


Recommendation

  • According to the USDA NOP, organic crops grown in manure amended soils must be withheld from harvest after application:
    • 120 days – edible portion of crop that come in direct contact with soil, can be splashed by soil (rain, irrigation)
    • 120 days – leafy greens, melons, squash, peas, and other vegetables
    • 90 days – all other food crops including tree fruits, sweet corn
  • This withholding period is to allow for the reduction of pathogenic organisms, allowing for the harvest of safe produce

Skin Microflora of ICLF Workers

Microflora on the forearm of ICLF workers
Figure 20. Microflora on the forearm of ICLF workers
Skin microbiome of ICLF workers
Figure 21. Skin microbiome of ICLF workers
Forearm skin microbiome of ICLF workers
Figure 22. Forearm skin microbiome of ICLF workers
Diversity of ICLF workers’ forearm microbiome, genus level
Figure 23. Diversity of ICLF workers’ forearm microbiome, genus level

Animal Waste

Soil microbiome contains composted animal waste

ICLFs practice sustainable sourcing of soil amendment for use as natural fertilizer and soil conditioner for crop production. Crop fertilization by soil incorporation of aged manure or compost may introduce different microbes and alter the soil microbial community. We aim to characterize the influence of aged or composted manure application on the diversity of soil bacterial community in ICLFs. Soil samples from six ICLFs in Maryland were collected before (pre-crop) and during the season (2020-2021) and used to analyze soil bacterial microbiome by 16S-rRNA gene sequencing.

Abundance of microbial phyla in animal waste containing soil
Figure 24. Abundance of microbial phyla in animal waste containing soil
Bacterial genus at pre-season and growing-season in soil containing animal waste
Figure 25. Bacterial genus at pre-season and growing-season in soil containing animal waste
Bacterial genus at various farms in animal waste containing soil
Figure 26. Bacterial genus at various farms in animal waste containing soil
Bacterial diversity/commonness in soil containing animal waste
Figure 27. Bacterial diversity/commonness in soil containing animal waste

Effects of Berry Pomace Extract

Plant-derived compounds used to remove pathogens from ICLF produce products

  • Berry fruits are antioxidant, antimicrobial, anti-inflammatory and vasodilators
  • Pomace accounts for as much as 20%–30% of the weight of the processed fruit
  • Fruit processing industries generate a huge amount of pomace (>27 million lbs from blueberry and >130 million lbs from blackberry)
  • Easy to use and should not interfere with growth of animal and product quality
  • Consumer friendly
Berry Pomace Extract (BPE) preparation
Figure 28. Berry Pomace Extract (BPE) preparation
HPLC/high mass accuracy TOF mass spec. of BPE
Figure 29. HPLC/high mass accuracy TOF mass spec. of BPE
Inhibitory effect of BPE on zoonotic pathogens
Figure 30. Inhibitory effect of BPE on zoonotic pathogens
BPE on probiotics and normal bacteria
Figure 31. BPE on probiotics and normal bacteria
Reduction of produce contamination by BPE
Figure 32. Reduction of produce contamination by BPE

Conclusion and Future Direction

  • Prevalence of SE and STEC was high in samples collected from organic farm environments
  • Soil and compost were determined to contain a higher percentage of both pathogens
  • Isolates displayed different patterns of sensitivity towards a wide array of commonly used antibiotics
  • Skin microbiome of farm workers from ICLFs showed a higher level of diversity
  • The concentration of BPE showed inhibitory effect on Salmonella and other foodborne pathogens, but such concentrations were not lethal for beneficial microbes
  • BPEs could be an option for promoting safety of organic food but need commercial farm base trial
See our recommendations

Acknowledgements

  • Farm owners and workers
  • Lab Members:
    • Dr. Mengfei Peng (Postdoctoral Fellow, ANSC, UMD)
    • Dr. Serajus Salaheen (Scientist, USDA-ARS, Beltsville, MD)
    • Zajeba Tabashsum (Ph.D. Student, MOCB, UMD)
    • Arpita Aditya (Ph.D. Candidate, ANSC, UMD)
    • Zabdiel Alvarado-Martinez (Ph.D. Student, MOCB, UMD)
  • CFS3:
    • Dr. Salena Parveen, Professor, UMES, and her team
    • Dr. Pat Millner, ARS-USDA
  • UME:
    • Jeff Semler, Extension Agent, UMD
    • Shauna Henley, Extension Agent, UMD
    • Mike Dwyer, Director, UME, UMD