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Microbiological analyses of fresh fruits and vegetables produced by organic and conventional farmers in Minnesota were conducted to determine the coliform count and the prevalence of Escherichia coli, Salmonella, and E. coli O157:H7. A total of 476 and 129 produce samples were collected from 32 organic and 8 conventional farms, respectively. The samples included tomatoes, leafy greens, lettuce, green peppers, cabbage, cucumbers, broccoli, strawberries, apples, and seven other types of produce. The numbers of fruits and vegetables was influenced by their availability at participating farms and varied from 11 strawberry samples to 108 tomato samples. Among the organic farms, eight were certified by accredited agencies and the rest reported the use of organic practices. All organic farms used aged or composted animal manure as fertilizer. The average coliform counts in both organic and conventional produce were 2.9 log most probable number per g. The percentages of E. coli-positive samples in conventional and organic produce were 1.6 and 9.7%, respectively. However, the E. coli prevalence in certified organic produce was 4.3%, a level not statistically different from that in conventional samples. Organic lettuce had the largest prevalence of E. coli (22.4%) compared with other produce types. Organic samples from farms that used manure or compost aged less than 12 months had a prevalence of E. coli 19 times greater than that of farms that used older materials. Serotype O157:H7 was not detected in any produce samples, but Salmonella was isolated from one organic lettuce and one organic green pepper. These results provide the first microbiological assessment of organic fruits and vegetables at the farm level. [ABSTRACT FROM AUTHOR]

Decimal reduction time (time to inactivate 90% of the population) (D) values of Bacillus anthracis spores in milk ranged from 3.4 to 16.7 h at 72°C and from 1.6 to 3.3 s at 112°C. The calculated increase of temperature needed to reduce the D value by 90% varied from 8.7 to 11.0°C, and the Arrhenius activation energies ranged from 227.4 to 291.3 kJ/mol. Six-log-unit viability reductions were achieved at 120°C for 16 s. These results suggest that a thermal process similar to commercial ultrahigh-temperature pasteurization could inactivate B. anthracis spores in milk. [ABSTRACT FROM AUTHOR]

Competing Interests: All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. Adam J. Ratner reports personal fees from Pfizer and Janssen, outside the submitted work. No other potential conflicts of interest were disclosed.

The United States Food and Drug Administration and the Department of Agriculture jointly published the "Guide to Minimize Microbial Food Safety Hazards for Fresh Fruits and Vegetables," which is used as a basis for Good Agricultural Practices (GAP) audits. To understand barriers to incorporation of GAP by Minnesota vegetable farmers, a mail survey completed in 2008 was validated with visits to a subset of the farms. This was done to determine the extent to which actual practices matched perceived practices. Two hundred forty-six producers completed the mail survey, and 27 participated in the on-farm survey. Over 75% of the on-farm survey respondents produced vegetables on 10 acres or less and had 10 or fewer employees. Of 14 questions, excellent agreement between on-farm interviews and mail survey responses was observed on two questions, four questions had poor or slight agreement, and eight questions had no agreement. Ninety-two percent of respondents by mail said "they took measures to keep animals and pests out of packing and storage buildings." However, with the on-site visit only 45% met this requirement. Similarly, 81% of respondents by mail said "measures were taken to reduce the risk of wild and/or domestic animals entering into fruit and vegetable growing areas." With direct observation, 70% of farms actually had taken measures to keep animals out of the growing areas. Additional, on-farm assessments were done regarding employee hygiene, training, presence of animals, water sources, and composting practices. This validation study demonstrated the challenge of creating nonleading and concise questions that are not open to broad interpretation from the respondents. If mail surveys are used to assess GAP, they should include open-ended questions and ranking systems to better assess farm practices. To provide the most accurate survey data for educational purposes or GAP audits, on-farm visits are recommended.