Embed Size (px)
Citation preview
• Antimicrobial chemicals and co-treatments are a primary preventive control to minimize or eliminate microbial cross-contamination in produce postharvest treatments and handling processes
• Even single-pass water uses benefits from antimicrobial addition
• Demonstrating that the antimicrobial dose in relation to overall water quality controls in use at each operation is scientifically- valid and verified (effective) for preventing cross-contamination is the critical task of compliance
• The owner, operator, or agent in charge of a facility shall … evaluate the hazards that could affect food manufactured, processed, packed, or held by such facility, identify and implement preventive controls to significantly minimize or prevent the occurrence of such hazards and provide assurances that such food is not adulterated … or misbranded …, monitor the performance of those controls, and maintain records of this monitoring as a matter of routine practice.”
OR Why, we’re exempt from FSMA
Levels of Postharvest Water Quality Management: Recirculated Systems
Remind me to come back to this
Where do I start?Determine antimicrobial uniformity and “low spot”
Antimicrobial Wash Process
30 ppm
10 ppm
25 ppm
25 ppm20 ppm
5 ppm20 ppm
15 ppm
“Low spot”
• Validation study sponsored by McEntire Produce, SC• 7‐step water purification process • Double pass reverse osmosis includes UV and HOCl treatment • Available technology to industry
• antimicrobial stability • quality and sensory effects on the product • worker safety and OSHA compliance • corrosion effects on equipment • waste water treatment and discharge• environmental impact• cost • availability (scale‐appropriate units)
• A measure of mineral content in the water• Mineral composition impacts the pH buffering capacity of water• High hardness can promote mineral deposits on equipment
• Propensity to build scale and biofilms• Soft water more prone to foaming
• Less tolerance for organic load
Water chemistry – Hardness
Water Quality Considerations
• Water chemistry affects process control!
• Packing facility water should be analyzed for:
• Hardness ‐ both Ca & Mg
• Silicates
• Iron
• Some water conditioning may be required
• Water Chemistry can vary seasonally & by source
• Retest or review annually
Hardness Interferes with Effective Dose Management
•Acidification (lowering pH) is more difficult•Different but may relate to alkalinity
•Hard water increases scale‐formation•Calcium and Magnesium content
•Produces more foaming in wash lines
COD: Chemical Oxygen Demand A Key Parameter of Wash Water Management
Start Finish
The More Dissolved and Suspended Solids, the Longer it takes to Kill
How long does it take to kill one million Salmonella Newport cells in wash water?
Time (sec)
Turbidity (FAU)
25 ppm 50 ppm1050
2577
40 °C104 °F
1050
2577
40 °C104 °F
0 15 10 <5 15 <5 <5
20 >120 15 5 45 5 <5
40 >120 30 5 >120 5 <5
160 >120 >120 >120 >120 120 75
Example: Impact of COD on Pathogen Inactivation in Flume Water: Diced Onion
0
1
2
3
4
5
6
0 5 10 20 30 45 60 75 90
E. coli O157 ‐ COD 20Salmonella ‐COD 20Listeria‐ COD 20E. coli O157 ‐ COD 140Salmonella ‐COD 140Listeria‐ COD 140E. coli O157 ‐ COD 280Salmonella ‐COD 280Listeria‐ COD 280
mg/L O2
Time (sec)
Log CFU/m
l
Standard limit of detection
0
1
2
3
4
5
6
0 5 10 20 30 45 60 75 90
E. coli O157 ‐ COD 20E. coli O157 ‐ COD 140E. coli O157 ‐ COD 280
mg/L O2
Time (sec)
Log CFU/m
l
Standard limit of detection
Example: Impact of COD on Pathogen Inactivation in Flume Water: Diced Onion
Wash Water SanitationOrganic Load vs. Chlorine Demand
PI ‐ Sunny Luo Co‐Pi’s and Collaborators David Teng, Sam Van Haute, et al.
USDA‐NIFA Project: Safety Innovations and Preventive Controls during Fresh and Fresh‐Cut Produce Washing, Packing, and Retail Display
Origination of Project Maintaining sufficient amount of free chlorine in wash water is critical to prevent pathogen cross‐contamination.
Organics deplete free chlorine (FC) rapidly during fresh produce washing.
Chlorine demand (CD) prediction is important for maintaining optimal FC level.
The contribution of chemical composition of wash water to organic load and CD unknown.
Research Objectives• Identify the key chemical compounds that are responsible for chlorine demand during fresh‐cut veg washing:
• Chemical compounds and concentration• Release rate • Impact on chlorine demand
The ultimate goal is to support the industry for targeted removal of chemical compounds to support safe water reuse and retention of chlorine concentration for food safety.
Factors affecting chlorine demand in fresh‐cut cabbage wash water
How reactive?
How much?
Organic molecules are present in different amounts & have different reactivity with chlorine; so they contribute to CD to different extent.
Contribution of cabbage wash water components to Chemical Oxygen Demand (COD)
91%
4%
1%
4%
5%
Contribution of specific classes of cabbage wash water components to chlorine demand
Fast reaction (15 min)Glucosinolates 7%
Sugars 6%
Organic acids 15%
Phenols 15% Proteins 57%
Slow reaction (120 min)
Glucosinolates 9%
Sugars 16%
Proteins 44%
Phenols 17%
Organic acids 14%
Take Home Messages
Organic load contributes to chlorine demand.
Organic load ≠ chlorine demand.
The impact of different organic molecules to chlorine demand changes over time.
Product and Non‐product organic molecules contribute different OM
Higher concentrations of COD arrive with cull product and with non‐product organics
Want to know more?
Neutralization delay (min)
Cumulative Log Reduction
Enterobacteriaceae1 1.542 2.643 3.074 3.545 3.73
10 4.1515 4.15
• 15 ppm HOCl at pH 6.8 and COD = 80 mg/L O2
• Neutralized with sodium thiosulfate at intervals to determine continuing log reductions due to no added neutralizer
Chlorine dioxide (ClO2) alternative to hypochlorite
• Oxidizer 2.5x “more effective” than chlorine (more killing)
• No formation of by‐products • Effective at wide pH ranges• Regulated dose limitations (3‐5ppm)• Requires potable rinse (<0.8 ppm)
On‐site Generation Process
2 Chemical Process – 80% efficient5NaClO2 + 4HCI = 4ClO2 +2H2O + 5NaCl
3 Chemical Process – 100% efficient2NaClO2 + NaOCl + 2HCI = 2ClO2 +3NaCl +H2O
Chlorine Dioxide OxidationClO2 + 4H+ + 5e‐ = Cl‐ + 2H2O
In‐line Monitoring, Dosing, and Documentation
Melon Flotation Pool –Southeast U.S.
Non‐chlorine alternatives are increasingly main‐stream
Peroxyacetic Acid Sanitizers
• Approved as water treatment
• May require post‐treatment rinse
• Approved for all food‐contact surfaces
• Mode of Action:•Causes oxidation of cellular constituents•Metabolic “poison” …cell death appears to continue in storage
H2O2 + CH2COOH H3COOHHydrogen Acetic PeroxyaceticPeroxide Acid Acid
•Break‐down products: acetic acid, O2, CO2, H20
• Permitted dosage (FDA):
• Cleaning surfaces 85 – 300 ppm
• Contact with food 80‐85 ppm maximum• Typical rates 30‐35 ppm
PEROXYACETIC ACID
Peroxyacetic Acid (PAA) Advantages
Less impacted by organic matter and soil Low foaming Very good biofilm penetration Very good on molds and spores
PAA In‐Line Amperometric Sensors
Evaluation of Surface Washes – Commercial Batch
> 99.99% kill
Peroxyacetic Acid Disadvantages
Corrosive to soft metals and skin Strong, pungent odor of concentrate and dilute forms
(worker discomfort & safety) Varied activity against fungi Build up of acetic acid in water; translucency Need to monitor water turn‐over closely Prolonged exposure may cause product damage
Peroxyacetic Acid (PAA) Advantages II
Perceived disadvantages • Unit cost is higher than sodium hypochlorite
• In reality, requires complex comparisons
• Will cause injury to some tender commodities• Typically a problem of infrequent water turn‐over• May be result of too low pH
• Pungent odor and irritation at higher doses• Generally only with high aerosolization
Highly effective oxidizer No residue concerns converts to Oxygen
Negligible DBP’s Kills pathogens Cl doesn’t
Ozone (O3)
Small‐Scale O3 System
Ozone (O3) Disadvantages
Unstable (short half life) Low solubility; best in cold water Difficult to monitor concentrations Difficult to adjust needs based on demandMay require use of secondary disinfectantMust be generated on siteWorker Safety Issues, Toxicity Highly Corrosive and Degenerative
Why wouldn’t ozonation be a sensible treatment in this spray‐wash system?
Organic Acids – Small to Midsize Grower Options
Lactic Acid & Phosphoric Acid• Needs adequate contact time• Combined with plant extract surfactants
However!!!Read the label carefully for your state
Not all state Department of Public Health or Auditors will ignore this discrepancy
KeystoneAntimicrobial Fruit & Vegetable Treatment
All components are Generally Recognized As Safe (GRAS) or have been cleared by the FDA for the intended use in a no‐rinse application.
Keystone Antimicrobial Fruit & Vegetable Treatment
Keystone Antimicrobial Fruit & Vegetable Treatment reduces 99.9% of the pathogens E. coli, Listeria and Salmonella* in produce wash or process water.** EPA Reg. No. 1677‐234.Not approved for use in CA.
Active Ingredients: Dodecylbenzenesulfonic acid, sodium salt 1.23% Lactic Acid 17.29% Other Ingredients:.... 81.48% Total: 100.00%
Add to washing/processing vessel according to the table submerge and agitate fruits and vegetables for a minimum of 90 seconds. Drain thoroughly and allow to air dry. No rinse required.
370 Wabasha Street N St. Paul, MN 55102www.ecolab.com 1 800 35 CLEAN
EPA Approved Bleach Source for Small‐Scale Growers
THE CLOROX COMPANYConsumer Services DepartmentOakland, California 94612‐1888
ULTRA CLOROX® BRAND REGULAR BLEACH (EPA Reg. No. 5813‐50)
Approved Label May Limit Dose for Fruits and Vegetables
Example of Hypochlorite Labeled for Ag‐use with Higher Doses
5 gal sales unit Recommended
Use Rates
Afternoon Demo Will Cover More Topics
• ORP• Importance of pH • ATP Swabs• Simple Micro Testing Examples
Listeria Concerns are Back for Raw Agricultural Commodities
Published 2000
Broader definition of Ready to Eat will place greater emphasis on EMPs
Listeria monocytogenes recognized as a pathogen of concern in RAC and value-added produce
Listeria finds places to grow on equipment and can persist for decades
L.m. in etched stainless steel H. O¨ lmez, S.D. Temur / LWT ‐ Food Sci. and Technology 43 (2010) 964–970
L.m. biofilm on lettuce
Non‐binding recommendations
DRAFT – not for implementation
Comments by July 17, 2017
Dump and Transport Precooling operations Quality treatment Pre‐grade and sort Pre‐pack conditioning or storage Packing Pre‐shipping cooling
11,2,3
2 2 2
3,4
4
1
Zone 1 & 2 surfaces may not be ‘internal’ with RAC
Shipping Area
Drain
Entrance
DETAILED SPATIAL MAPPING CAN REVEAL RESIDENT ESTABLISHMENT
Office
Cold RoomB
Cold RoomA
HPW WaxHF
Bin Dumper
UVSortingRoom
Drier
Bin DrierBin
Washer
Drain
Drain Packing RoomReceiving Room
Receiving Product
Listeria spp.
Listeria monocytogenes
Both together
123
4 7 8
5
6
9
10
111214
16
20
25 24 23 22 21
26 27
19 18 17
282930
31 32 33
363534
41 4239 4043
44 45
15
13
SCHEMATIC FACILITY
Primary Post‐enrichment Screen
Presumptive Lm colonies
qRTPCRvirulence confirmation and serotyping
PFGE Facility & Temporal Diversity Mapping
WGS source‐tracking T. Suslow et.al. , unpublished 2014‐16
Linking isolates to spatial and traffic‐flow mapping More definitive source‐tracking Better resolve transient and resident Lm Data‐based evidence for a needed Correction or improved Best Management Practice
Examples of bin drenchers
• Prevents Scald in CA storage• Solution retained for > 1 week• Lm found in multiple locations
Image by T. Suslow not from Bidartfacility
Typical x‐y‐z vector swabbing
Swab after > 3 hours into run
United Fresh Listeria Guidance
Released 2013
Questions?
70“Oh, if only it were so simple.”
