Improvement of the safety of food handling practices on small farms

Final Report for LS09-217

Project Type: Research and Education
Funds awarded in 2009: $200,000.00
Projected End Date: 12/31/2013
Region: Southern
State: South Carolina
Principal Investigator:
Dr. Paul Dawson
Clemson University
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Project Information


To identify risk factors for specialty crops in SC, the research team conducted a bacterial assessment of products and farms and also administered a survey to farmers and consumers. We collected samples of fresh produce being sold at farmers markets within 2 regions of South Carolina (Coastal, Upstate). Produce samples were enumerated for total aerobic organisms and coliforms and these data are still being analyzed to determine if there are regional, seasonal or product effects in bacterial levels. A consumer and farmer survey was to determine consumer expectations and misconception about locally grown produce and producers beliefs on how to market their product. Results show that consumer priority for purchasing produce rank “locally grown” over “organic.” The research team participated in 2 GAP workshops in cooperation with the SC Department of Agriculture to deliver food safety information to small farmers in South Carolina.

Project Objectives:

The goal of this project is to identify risk factors for food safety in the processing of specialty crops on small farms and to develop more effective and targeted interventions for foodborne illness prevention. We propose four objectives to accomplish this goal: 1. To develop a more complete characterization of food handling, hygiene, and sanitation practices that contributes to foodborne illness by conducting observations of harvest and packing practices on small farms in the SE US. 2. To identify foodborne illness risk factors and effective control strategies using the findings from the observations and microbiological testing results. 3. To develop, deliver, evaluate, and disseminate training interventions targeting farm managers based on identified risk factors and control strategies to increase their competency in delivering educational messages to farm workers. 4. To determine consumer perceptions of specialty products, especially organic and locally grown produce.


The U.S. Department of Agriculture’s (USDA’s) Economic Research Service (ERS) estimates that foodborne pathogens, including Campylobacter, Salmonella, Escherichia coli O157:H7,
E. coli non-O157:H7 STEC, Listeria, and Toxoplasma gondii, cause $23 billion in medical costs, lost productivity, lost wages and premature deaths in the United States each year. IN the past 10 years, outbreaks of human foodborne illnesses due to consumption of produce have increased in the U.S. and this increase may be related to changes in the produce industry and food consumption patterns. The USDA-ERS reported that U.S. agriculture hire 1.01 million farm workers in 2006 to work with 2.05 million self-employed farmers and unpaid family members. All of these individuals are planting, maintaining crops, harvesting and processing produce. It stands to reason that these individuals need food safety training as outlined in the current proposal. This study examined specialty crops primarily sold at local and regional farmers markets for bacterial levels and also surveyed farmers and consumers on perceptions of organic and local food products for preference and perception of quality.


Materials and methods:

Produce samples from regional farmers markets in SC were sampled for bacterial levels to determine a baseline level and to determine if the region or product type affected these levels. Bacterial sampling of a peach processing facility in the state was conducted from harvesting through final product packing. A survey tool was developed to determine consumer perceptions of locally-grown produce and this survey has been tested on students and staff at the university. A survey for small farmers was also been developed and the university internal review board has approved all surveys for human subjects.

Research results and discussion:

We have completed data collection of produce samples from farmers markets located in different parts of South Carolina. Overall, farmers’ market samples carried over 5 log population of total aerobic bacteria and 4 logs of Enterbacteriaceae. 11 different products were sampled in 7 different county farmers markets and fruits generally had lower bacterial populations than vegetables. Variables having an effect on bacterial counts included the region of the market (Coastal vs. Upstate), type (fruit vs. vegetable), growth location (ground level, under ground, tree/bush) and whether the product was from a climacteric or not.

Produce purchased from Farmer’s Markets located in the coastal region of the state had higher Enterbacteriaceae populations than produce purchased on the Upstate while total aerobic counts varied depending on methodology (whether petri film or plate count agar was used) (Table 1). Vegetable products had higher bacterial populations than fruit products, which is likely related to the growth location (ground level, below ground, above ground) since more fruits grow in trees and bushes than vegetables, many of which grow at or below ground level. The relative bacterial population of produce due to growth locations was: below ground>at ground level>above ground level. Finally, non-climacteric produce had greater Enerbacteriaceae populations than climacteric products but did not differ in total aerobic bacterial populations.
Sampling of a peach processing facility found high bacterial levels on workers hands that were harvesting peaches however these bacterial levels and type (Staphylococcus predominantly) were not found on peaches at the end of the process. Containers used to transport peaches to the processing line were found to have low bacterial levels (< 2 logs per 4 x 4cm swab) after washing but higher populations (~4 logs per 4 x 4 cm swab). Based on the bacterial measurements taken throughout the process, human handling at harvest contributed to the greatest contamination of peaches however the cleaning and sanitizing steps after harvest appeared adequate to remove reduce bacteria to a safe level. Members of the SARE project team have given presentations at four GAPs training workshops in cooperation with the SC Department of Agriculture. A survey was conducted to identify current farming practices, educational needs, and preferred method of educational information distribution to local produce farmers in the Southeast (IRB2010-324). Surveys were distributed during workshops on Good Agricultural Practices (GAPs). Thirty-one surveys from 31 different farms were completed and returned. Most of the farmers (71%) who participated in this survey reported that they use conventional farming practices and most distribute their produce at farmers markets, retail sales or wholesale. Farmers reported that the most popular method of advertising for sale of produce was through ‘word of mouth’ (84%), followed by advertisement on the internet (58%) or printed newspaper (48%). When the farmers were asked to identify the most important challenges that affected their long term success, ‘weeds’ were selected by 77% of the farmers, followed by rainfall/moisture or labor (both at 74%) and soil nutrients (68%). GAPs certification was reported as a challenge by only 13% of the farmers. Sixty-eight percent of the farmers reported that they were ‘not sure’ if they needed additional educational training on farming practices from the local University; however, they (68%) were interested in receiving information on organic agriculture.
Another survey was conducted to determine consumer perceptions and purchasing decisions of fresh produce (IRB2010-324). Four-hundred and eight consumers were surveyed in the Southeast at local grocery stores. Seventy-two percent of the survey respondents were female, and most of those completing the survey were 18-29 years of age (27%), 60-69 years of age (20%), or 50-59 years of age (15%). Sixty-one percent of the respondent indicated that they purchase fresh produce on a weekly-basis, while another 15% reported purchasing fresh produce on a monthly basis. More than one-third of the consumers who were surveyed did not know about the “certified” state marketing programs through the State’s Department of Agriculture (for example “certified SC grown” through the SC Department of Agriculture). Sixty-two percent of the respondents indicated that they purchased organic produce. Eighty-five percent of these respondents who reported purchasing organic produce indicated they would choose locally-grown produce over organic produce. The respondents that reported that they ‘never eat organic produce’ were asked to rank the reasons for this decision, and the ranking was as follows:
Too Expensive > Not Convinced of the Benefits = Not Always Sure If It Is Labeled Properly > Lack of Information > Not Available Where I Shop
These data demonstrate that cost remains the most important reason for consumers who do not purchase organic produce. Data also shows that consumers who purchase organic would rather buy local produce.
A study was conducted to evaluate the chemical composition and quality attributes of certified organic and conventional fresh collard greens (Vates variety) grown in the controlled environment of a greenhouse. Previous research has suggested that organic produce may be higher in certain nutrients than their conventional counterparts. One of the suggested nutrients to be influenced by production practices are polyamines; however, there is limited evidence to support this claim. Amines such as diamines (putrescine and cadaverine) and polyamines (spermine and spermidine) are important in the regulation of nucleic acid function, protein synthesis and the stabilization of membranes. They can be found in certain foods, including fruits and vegetables. In this study, USDA organic and conventional collard greens were grown in a controlled environment to examine the effect of cultivations practices on level of polyamines in the leaf-tissue and to determine influence of cultivation on other collard quality attributes. Organic collard-plants weighed less than their conventional counterparts (at maturity of 75 days after planting, or extended growth of 91 days after planting) and were lighter in color than conventional collards (P < 0.05). When collards were grown during the summer months, organic collards contained higher levels of spermidine (18.0 nmol/g) as compared to the level of spermidine found in conventional collards (6.8 nmol/g). Polyamines were found to be associated with higher yellow color values (+b scores) on the leaves of organically grown collards- a factor that may be used as a rapid method for predicting higher levels of polyamines in collard greens.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

The research team participated in 2 GAP workshops in the state reporting findings and delivering food safety training. 1 manuscript is published and 2 manuscripts are in preparation for publication and 2 posters were presented at National meetings.

Steinberg, E. L., R. M. Dawson, P. L. Dawson and J. K. Northcutt. 2013. Consumer perceptions and purchase decisions of organic and conventional fresh produce. Submitted to the Journal of Food Products Marketing. Taylor and Francis Group; ISSN 1045-4446 (Print), 1540-4102.

Project Outcomes

Project outcomes:

The proposed research will fill gaps in our current knowledge regarding risk factors for foodborne illness on small farms. The findings from the observational and microbiological analysis are being used develop targeted training interventions. Unlike other educational materials that have been developed, the materials will be targeted to food safety educators so that they are equipped with the required knowledge and competency to deliver messages on food safety to small farmers. Thus, it is expected that small farm workers will exhibit safer practices following educational efforts and thus help reduce the risk for foodborne illness. Furthermore, determination of consumer perceptions and preferences for produce will assist small farmers in developing successful marketing plans.

Economic Analysis

According to the SC Department of Agriculture, agribusiness (includes farming and forestry) has the greatest economic impact on the state of any industry ($33.9 billion/year). Jobs and labor income are 200,000 and $7.5 billion per year, respectively and 92% of all land in the state is used for agribusiness. THE number of farms in SC has increased from 24,500 to 25,800 in the past 5 years while other neighboring states have seen a decrease in this number. More than 4,000 women are principal farm owners and 90 farms produce organic crops on more than 1,00 acres with 2,000 acres in the process of being converted to organic production. Thus, the importance of maintaining the safety of food produced in SC is paramount as a food safety event could devastate the State’s economy.

Farmer Adoption

SC small farmers were surveyed and of the over 30 respondents, 22 sold their products at farmers markets, 16 at retail stores, 8 at wholesale and 7 directly to restaurants. Most cited environmental issues (weather, pests, disease) as their greatest challenge to success, around 12% listed GAPs as an important factor. At the same time only about 12% responded they did not need additional training on food safety issues from the state land grant institution. We have not completed our analysis on adoption of the food safety practices presented to small farmers through the several workshops the research participated in.


Areas needing additional study

More data on farm worker sanitation would be helpful to determine the impact of this on food safety. These are difficult data to gather due to the transient nature of many workers and seasonal aspect of the products being harvested and produced. The economic and safety impact of added regulations should also be studied. It may be that the good intentions of added regulations for improving the safety of the food supply are actually having little effect on the safety of the food but having a severe negative effect on the ability of famers to succeed and expand the availability of fresh, locally grown food.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.