UMASS FOOD SCIENCEEXTENSION RESEARCH

SANITATION AND VALIDATION OF PRODUCE RINSE WATER TO ENHANCE FOOD SAFETY

Results

Wash Solutions Turbidity (NTU)

NaClOadded (ppm)

ResidualFree Cl

(HACH ppm)

ORP# 1 ORP# 2

E.coli O157:H7Target: 650-800 mV

Clean H2OControl: 0 NTU 0 0 444.6 455 +

0 NTU 50 50 680.7 701 -

Soil + H2OControl: 50 NTU 0 0 475.3 457 +

25 NTU 50 25 693.0 700 -50 NTU 50 50 718.8 717 -

Cucumber + H2O

Control:50 NTU 0 0 350.0 303 +25 NTU 50 11 834.9 830 -50 NTU 50 1.2 584.3 560 -

Cucumber + Soil

Control:50 NTU 0 0 381.0 370 +25 NTU 50 13 761.6 774 -50 NTU 50 10 833.1 816 -

Organic Challenge

H2O

Control:2.5g/L TOC/TDS 0 0 220.1 223 +2.5 g/L TOC/TDS 50 0 209.9 224 +2.5 g/L TOC/TDS 200 0 211.8 210 +

Comparison of ORP Measurements with Reduction of E.coli O157:H7 by Chlorine Bleach in Different Turbid Organic Matter Wash Solutions

Wash Solutions(50 NTU)

Free Chlorine (ppm)Standard

HACH Fr1 Fr2 Fr3

Clean H2O0 ppm 0 0 0

50 ppm 50 > 10 50

Soil + H2O0 ppm 0 0 0

25 ppm 25 > 10 Between 10-5050 ppm 50 > 10 50

Cucumber + H2O

0 ppm 0 0 04 ppm 50 2.0 10

**10 ppm **< 25 **0.2 **50

Cucumber + Soil

0 ppm 0 0 05 ppm < 25 2.0 Between 10-50

25 ppm < 25 0.6 50

Organic Challenge H2O

0 ppm 0 0 00 ppm 0 0 00 ppm 0 0 0

Comparison of Free Chlorine Test Strips in Turbid Organic Matter Wash Solutions

Cucumber Matter Affects Free Chlorine Strips Readings

Wash Solutions Standard HACH Fr1 Fr2 Fr3

Cucumber + H2O0 ppm 0 0 04 ppm 50 2.0 10

**10 ppm **< 25 **0.2 **50

Control50ppm Free Cl2

Consistent

Cucumber + H2O**10ppm Free Cl2

Inconsistent

Fr1 Fr2 Fr3

**Fr1 **Fr2 **Fr3

10ppm <2 5ppm 10ppm ≠0.2ppm 10ppm ≠ 50ppm

Conclusions• Presence of residual Free Chlorine reduced E.coli O157:H7 ATCC

43895 suspended in various turbid wash solutions.

• Vegetative organic matter can impact Free Chlorine Test strips with inconsistent readings.

• Portable ORP meters gave consistent results in controls and organic matter solutions. ORP may be a good indicator of sanitizer activity if kept within 650-800 mV range. • However high turbid vegetation reduces ORP below threshold

• Free Chlorine Test strips are a cheap fast method of rapid method monitoring. However inconsistent readings will occur in high turbid vegetative process water.

UMass Work In progress

Best Practices for Implementing an On-Farm Food Safety Plan

• Documentation• Environmental monitoring

– River shed– On-farm facilities– Operators

• SOP• Extension Programming

Microbial Counts from the CT River

Average MPN and Average E.coli/ Coliform MPN of all water samples taken from the Connecticut River from June 2014 to October 2014.

6/13/2

014

6/20/2

014

6/27/2

014

7/3/2

014

7/10/2

014

7/17/2

014

7/24/2

014

7/31/2

014

8/8/2

014

8/15/2

014

8/22/2

014

8/29/2

014

9/19/2

014

10/3/2

014

10/31/2

0140.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

1028.92

1625.58

>2419.6>2419.6

1265.81

824.18

1559.13

>2419.6

819.59

>2419.6

559.41653.88501.91

1756.46

586.17

35.19 38.07

1950.14

1160.59

32.86

305.1693.73 109.73 38.01

1090.69

15.52 115.74 22.50173.89

35.79

Average MPN From CT River

Average MPN Average E. coli MPN Upper Limit of Quanti-Tray 2000Maximum CFU per 5 Samples

Date

MPN

/ 100

mL

Packing house Drain

6/5/2

014

6/12/...

6/19/...

7/3/2

014

7/10/...

7/17/...

7/24/...

7/31/...

8/9/2

014

8/14/...

9/19/...

10/3/...

10/17/...

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

1.00E+09

ColiformAPC

CFU/

mL

Average APC and Coliform Plate Counts for samples taken from drain grate closest to packing area door from June 2014 to October 2014.

H1 Day 1 H1 Day 2 H1 Day 3 H2 Day 1 H2 Day 2 H2 Day 3 H3 Day 11.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

9.99E+00

7.90E+06 5.18E+06

9.99E+00

2.46E+06 3.20E+06

9.99E+00

7.00E+043.31E+05 2.23E+05

8.60E+04 1.53E+05 2.66E+05 2.35E+05

On Farm Harvesting Hand Samples

APC Coliform

Average APC and Coliform Plate Counts for samples taken from farm workers hands August 2014 to October 2014

Next Steps

• Develop and implement SOPs• Establish training program• Continue environmental monitoring• Extension Activities

– On-line materials– Workshops for best food safety practices

Validation of Commercial Produce Sanitizers

Food Safety Validation• Lab analysis

– Physiochemical– Microbiological

• Organoleptic attributes• Operational implementation

– Dosage calculations– Cost per use

• Extension Dissemination

On Farm Research Needs Diagnostic tools that can support QA on-farm• Must Account for Resource Limitations

– Ease of use:• No/little sample preparation• No/little technical skills

– Account for the farming conditions• Limited electricity

– Affordable– Rapid

• i.e. Agricultural water cannot be used unless the issue has been resolved

Figure 3: Food-grade antimicrobial emulsions can be formed using a simple spontaneous emulsification method

Natural Antimicrobials for Produce Safety

• Strategy:– Natural– Non-thermal– highly effective

antimicrobial

• Science– Physiochemical emulsion stability– Antimicrobial activity– Product Development for application

Biosensors for Agricultural Water

Figure 1: The bacteriophage will be used to recognize, infect and replicate within Salmonella spp. cells. Once replication is complete, the replicated bacteriophage will burst out of the bacteria. The increase in bacteriophage numbers can then be quantified with a fluorescent dipstick.

Nugen, S. Bacteriophage Technology, CPS proposal,

2014.

Phage Amplification

+ =