Vegetable production chain

IV. TRANSMISSION OF HUMAN PATHOGENS IN MANURE, SOIL, AND WATER TO THE VEGETABLE PRODUCTION CHAIN... 

Franz, E. and van Bruggen, A. H. C. (2008). Ecology of E. coli 0157 H7 and Salmonella enterica in the primary vegetable production chain. Crit. Rev. Microbiol 34,143-161. 

Pathogen contamination can occur at every stage of the whole production chain from field-to-fork (Table 19.1). Nevertheless, besides other components of infection, manures derived from livestock are considered to be an important potential preharvest contamination source (Fig. 19.1). Several disease outbreaks have been associated with raw fruits and vegetables and unpasteurised products some have been traced back to livestock (Pell, 1997), but in the majority of the outbreaks associated with fresh produce, minimally processed products and unpasteurised products, the source of contamination remains unknown (de Roever, 1998). 

Example of successful integration of the HACCP concept in a vegetable supply chain to control product quality as well as safety... 

Badosa E, Trias R, Pares D, Pla M and Montesinos E. 2008. Microbiological quality of fresh fruit and vegetable products in Catalonia (Spain) using normalised plate-counting methods and real time polymerase chain reaction (QPCR). J Sci Food Agric 88(4) 605-611. 

Enteric pathogens have to be introduced into the production chain at some point in order to contaminate fresh produce. Direct fecal contamination of vegetables just prior to consumption represents the greatest risk (Gorny, 2002 Mukherjee et al., 2007). However, other sources of contamination such as manure amended soil and irrigation water are more commonly encountered (Hutchison et al., 2008 Islam et al., 2004). 

When EUREP held its annual conference in 2003, they used the opportunity to document the growth of the organization. In the four years from 1999, when the EurepGAP protocols were released, 12,000 growers had signed up to produce under the new system. This placed 394,000 hectares of fruit and vegetable production under EurepGAP protocols and included every major supermarket and food cooperative chain in Europe in the alliance. At the market end, over 200 companies were members of the alliance and this included every major supermarket and food cooperative chain in Europe. 

The alkaline product from the wood ash was a crude solution of sodium and potassium carbonates called "lye". On boiling the vegetable oil with the lye, the soap (sodium and potassium salts of long chained fatty acids) separated from the lye due to the dispersive interactions between the of the fatty acid alkane chains and were thus, called "lyophobic". It follows that "lyophobic", from a physical chemical point of view, would be the same as "hydrophobic", and interactions between hydrophobic and lyophobic materials are dominantly dispersive. The other product of the soap making industry was glycerol which remained in the lye and was consequently, termed "lyophilic". Thus, glycerol mixes with water because of its many hydroxyl groups and is very polar and hence a "hydrophilic" or "lyophilic" substance. 

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