Agriculture Reference
In-Depth Information
ensure the microbiological safety of composted manure, environmental factors sup-
porting pathogen regrowth need to be identifi ed and controlled.
Education on Safe Use of Raw Manure and Compost
Because most fruits and vegetables grow in an open environment, sources for contami-
nation can be multiple and variable. Complete elimination of enteric pathogens in fresh
produce growing on a farm is not practical. However, reducing the risks of produce
contamination with pathogens can be achieved by a systematic prevention approach
(Heaton and Jones 2008). The FDA developed Good Agricultural Practices (GAPs) to
provide guidelines and recommendations for fruit and vegetable growers to minimize
microbial contamination by addressing various agricultural activities involved in the
preplanting, planting, growing, harvesting and postharvest handling of fresh produce
(FDA 2001). As illustrated by Bihn and Gravani (2006), produce safety assurance can
be built on a strong foundation of GAPs with emphasis on microbial water quality,
manure use and composting, worker health and hygiene, and other areas.
Guidelines have been developed for farmers on how to treat and use animal waste
properly. According to USDA National Organic Program (NOP) standards, raw
manure must either be composted or applied to produce fi elds at least 120 and 90 days
before harvesting the produce where edible portions do and do not have contact with
the surface soil, respectively (USDA AMS 2000). The compost of plant or animal
materials must be produced through a process with a temperature of between 55 and
77 °C for a minimum of 3 to 15 days depending on types of composting system used
(NOSB 2002). Additionally, several fi eld studies have suggested that the time between
manure/compost application to fi elds and produce harvesting should be maximized,
and that properly composted manure, instead of raw manure, should be applied as
fertilizer (Ingram and others 2005; Islam and others 2004a-c). Clearly, proper applica-
tion of raw manure to produce fi elds, appropriate waiting periods, as well as effective
composting are essential to the successful implementation of GAPs. Although they
are not mandatory regulations, GAPs should be implemented by produce growers to
reduce the contamination of their products (Bihn and Gravani 2006).
It is estimated that in 1997 in the United States, nearly a third of “mixed vegetable”
(mostly vegetables) and herb crops were grown organically on a small farm or parcel
(Dimitri and Greene 2002). A survey of New York fruit and vegetable growers
revealed the lack of food safety concepts on waste management practices for manure
and compost application on the farm among small farmers (Rangurajan and others
2002). Therefore, food safety education programs, especially for small growers,
should focus on proper composting strategies to reduce pathogen numbers in animal
waste and on using compost safely for fruit and vegetable production.
Conclusion
The use of raw or improperly composted manure has been identifi ed as an either direct
or indirect source of many foodborne disease outbreaks due to consumption of fresh
produce contaminated with human pathogens. As a common agricultural practice,
