Faustino, I think that comparing to hydroponic plants, soil - grown crops can be more safe in contamination by  human pathogens - they are surrounded by antagonistic bacteria and bacteriophages that suppress pathogens. Microbial population around hydroponic plants is less studied, and it really can include more pathogenic bacteria. At least it was demonstrated by several experiments.

http://www.sciencedirect.com/science/article/pii/0273117794903220

http://thewatchers.us/pathogens/j1462-soil-rootzonebacteria.pdf

http://www.sciencedirect.com/science/article/pii/S0065216408004073

http://www.ejobios.com/pdf/EJOB-10-22-4-14-112-118.pdf

Faustino, I think that comparing to hydroponic plants, soil - grown crops can be more safe in contamination by  human pathogens - they are surrounded by antagonistic bacteria and bacteriophages that suppress pathogens. Microbial population around hydroponic plants is less studied, and it really can include more pathogenic bacteria. At least it was demonstrated by several experiments.

http://www.sciencedirect.com/science/article/pii/0273117794903220

http://thewatchers.us/pathogens/j1462-soil-rootzonebacteria.pdf

http://www.sciencedirect.com/science/article/pii/S0065216408004073

http://www.ejobios.com/pdf/EJOB-10-22-4-14-112-118.pdf

I think these crops can be infected by Water-based microorganisms which can be  easily introduced.

The contamination source for outbreak of food-bone diseases of a food can occur at any of the many points during production to market, not necessary only at a farm. So, hydroponic crops can be disease-free at producing center, but contamination can occur (infected by such as E. Coli O157:H7 ) at a factory during packaging or transportation, and lead to a disease outbreak. We had experienced some food disease outbreaks here. The investigation of such outbreaks conducted by authorities such as USDA would always involve in 'trace back to the true source of contamination', which involves in many spots from market to original producing places.

If the materials such as trays, rafts and beds used for hydroponic production are not well cleaned/disinfected, they will also cause hydroponic diseases for the plants. The resulting crops then will not be suitable for human consumption. Especially, they are indented to be consumed 'raw' (ex. salads).

See this article from Colorado State University Extension (http://www.ext.colostate.edu/ptlk/2043.html).

Title: "Root Disease Problems & Management in Hydroponic Systems""The most common root disease in hydroponic systems is root rot caused by the fungal-like organism, Pythium...........". 

Thank you.

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics

I think it can be, especially if the initial seed was contaminated. Early seedlings should be free of viruses or bacteria, thus further support the healthy hydroponics