Food Safety Lab
PRE-HARVEST FOOD SAFETY

BIOLOGICAL SOIL AMENDMENTS

IRRIGATION WATER QUALITY
• UVC treated irrigation water
Irrigation water is one of the several main sources of microbial contamination of produce during pre-harvest operations. The FSMA produce safety rule requires that the water used for pre-harvest operations of covered produce should meet the microbiological quality standards of 126 or less CFU generic E. coli per 100 mL water geometric mean (GM). Studies with UV light were conducted to improve the microbiological quality of water used for irrigation purposes and reduce the risk of contamination.
UVC

MICROBIAL DIE-OFF RATE CALCULATIONS
• Effect of weed vegetation
The environmental stresses have been found to cause detrimental effect on the survival and growth of microorganisms residing on produce surface. However, the level of exposure to those stresses may be affected by the vegetation growing in the farm covering the produce. The role of vegetation on the survival and attachment of microorganisms on ground fruits such as watermelons is investigated to determine on-farm microbial die-off rate.
weedA
Watermelon farm, LSU AgCenter Botanic Gardens
weedB
Inoculating the generic E. coli on the circular area of the watermelon surface
weedC
Bacterial attachment on watermelon surface over a period of time under SEM

HARVESTING PRACTICES
• On-farm microbial contamination of pecans
Cattle-grazing is one of the common forms of ground cover management systems in the pecan orchards which helps growers in providing a second source of income from same land and also reduces the mowing cost. However, cattle manure has been found to be one of the major sources of food borne pathogens like Salmonella, E. coli O157:H7 and Listeria monocytogenes and they can survive in the manure for several months. It possesses risk to pecans because they are harvested from the ground after the matured nuts fall off and they sit there for several days until collected. Additionally, runoff water, irrigation water, inadequately composted manure or the feces from wild animals may contaminate the soil of pecan orchards with food borne pathogens. Studies were conducted to determine the prevalence of foodborne bacterial pathogens on the harvested pecans using various test procedures (culture based, immune magnetic separation, latex agglutination, PCR, rapid tests).
pecanA pecanB

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