The effect of different fertilisers on hygienic quality of lettuce

Summary

Abstract – The effect of different fertiliser types (cal-cium ammonium nitrate, fresh farmyard manure, composted farmyard manure and nettle extract) on the hygienic quality of fresh and washed lettuce was tested in two trials in summer 2004 and 2005. The hygienic quality was described by total aerobic bacte-rial count and level of coliform bacteria, Escherichia coli, Salmonella Enteritidis, Enterobacteriaceae. No Salmonella Enteritidis was detected in any sample. E. coli was isolated independent of the fertiliser type in low concentrations. The total aerobic bacterial count, the levels of Enterobacteriaceae and coliform bacteria tended to be lower after application of mineral fertil-iser but on a very low level. The washing process had no significant influence on the hygienic quality of lettuce. No hygienic quality differences between in-corporated farmyard manure and farmyard manure left on soil surface or in upper soil layer were ob-served.