Summary
of On-Farm Food Safety Applied Research (Crops)
Research Projects:
Horticulture
baseline study 2004-2005:
What were the goals of this study?
To
study microbes present in selected Ontario fruits and vegetables.
What
did we learn?
E. coli was most prevalent in parsley (13.4%), followed
by:
- organic leaf lettuce (11.6%)
- leaf lettuce (6.5%)
- scallions
(6.4%)
- cilantro (4.9%)
- muskmelon (1.3%)
- head lettuce (0%)
- fresh
market tomatoes (0%).
Our recommendations
Farms should
focus on reducing risk for fruits and vegetables which
- have high
prevalence rates for E. coli; and/or
- have historically been implicated
in foodborne outbreaks.
Bioremediation
of persistent organic chemicals in soil 2005 - 2006:
What were the goals
of this study?
To assess two microbe-based products that can reduce total
DDT in soil.
What did we learn?
- Both products reduced
DDT in soil (44% and 32%). The more costly product was more effective.
- DDT
is not uniformly distributed within soil. It requires several soil samples (ideally
5 per plot) to assess DDT concentrations.
Our recommendations
- If DDT is a concern, work with a qualified professional to identify suitable
ways to reduce this toxin. The same applies to other organic pollutants.
- Keep
in mind that microbe-based products will not work during winter.
Assessment
of compost tea as a food safety risk 2005:
Why did we conduct this study?
To determine the potential food safety risks of using compost tea.
What
did we learn?
- E. coli exceeded the Canadian Council of Ministers
of the Environment (CCME) guidelines (100cfu/100mL) in the compost tea.
- Cryptosporidium
was present, E. coli O157:H7 and Salmonella were not.
- Safety of tea depended
heavily on the starting materials, which varied widely.
Our recommendations
- Compost tea should not contact the edible portion of crops that are eaten
raw.
- To limit food safety risks, brewers need to use high quality starting
materials (compost and other additives). They must also have a diligent sanitation
program in place.
Berry irrigation
water research 2004 - 2007:
Why did we conduct this study?
To determine the fate of microbes on berries as applied through overhead irrigation
where water exceeded the Canadian Council of Ministers for the Environment for
generic E. coli (100cfu/100mL).
What did we learn?
Water that
exceeded 100cfu/100mL of E. coli transfers E. coli to the berries, and may exert
a food safety risk.
Our recommendations
Test irrigation water.
If water exceeds 100cfu/100mL, and crops are eaten raw:
- install drip
irrigation
- extend the time between spraying and harvest.
Assessment
of water sanitation technologies used in horticulture dump tanks 2006 - 2008:
Why
did we conduct this study?
To assess seven sanitizing water treatments
against E. coli in the presence of organic matter (soil). The treatments studied
include:
- calcium and sodium hypochlorite
- chlorine dioxide
- two
different peroxyacetic acid
- UV
- ozone.
What did
we learn?
- All treatments reduced E. coli by at least 80%.
- High
levels of E. coli and organic matter reduced efficacy.
- Sodium and calcium
hypochlorite were less effective than all other treatments.
Our
recommendations
- We recommend sanitation of dump, wash or flume
tank water.
- The method will depend on your production system, crops produced
and budget.
Assessment of cadmium
uptake in soybeans 2006-2008:
Why did we conduct this study?
To identify soil factors which contribute to cadmium (Cd) accumulation in soybeans.
What
did we learn?
- Manganese, magnesium, calcium and increasing pH
protected against Cd accumulation.
- Cd and low pH contributed to accumulation.
Our
recommendations
The edible portion of some crops can accumulate higher
concentrations of Cd. Examples include cereal crops, leafy greens and root vegetables.
Farms should have the soil tested for Cd, pH and other elements that can compete
with Cd for uptake; for example Calcium, Magnesium and Manganese. This will help
identify whether soil may produce food which exceeds the recommended guidelines
for Cd.
Horticulture
Traceability Project 2006 - 2007:
Why did we conduct this study?
To identify traceability information management systems (TIMS) needs for the tree
fruit and oilseed industry, and if so, provide TIMS solutions to these industries.
What did we learn?
- These two sectors require TIMS.
- Out
of over 50 systems, there are 14 which meet the requirements of producers and
vendors within the tree fruit and oilseed industry.
Our recommendations
To learn more about these systems, please email Vanessa Taylor of OMAFRA at vanessa.taylor@ontario.ca.
Leafy green and fresh market
tomato project 2007-2008:
Why did we conduct this study?
- To identify points of potential risk during production, harvesting and packing.
- To
track contamination sources on end-product for fresh market tomato, lettuce, parsley
and spinach.
What did we learn?
- E. coli contamination
in lettuce, parsley and spinach increased from growth to packing.
- Contamination
came from irrigation, wash and hydro cooler water, workers hands and conveyor
belts.
Our recommendations
There are many different sources
of contamination on-farm. To reduce these food safety risks, we recommend that
farms implement one of these food safety programs:
- Agriculture Canada's
on-farm food safety programs (commodity specific), or
- the Ontario Advantage
Good Agriculture Practices program (whole farm approach).
Author:
Lindsay Arthur, OMAFRA, Applied Research Coordinator
- On-Farm Food Safety
Author credit:
Statisticians and experts
involved in the design and analysis of the research project(s): Grant Campbell
, Martha Fabri, Pam Fisher, Beverley Hale, Tamara Fernandes, Sandra Jones, Kelley
Knight, Janice LeBoeuf, Hugh Martin, Moustapha Oke, and Pat Turner.
