Use of raw and composted poultry litter in lettuce produced under field conditions: microbiological quality and safety assessment

CÉCCOLI, GABRIEL ; DAURELIO, LUCAS DAMIÁN; MUÑOZ, FERNANDO FELIPE ; BOUZO, CARLOS ALBERTO; PIZARRO, MARÍA DOLORES; FRIZZO, LUCAS S.

POULTRY SCIENCE

POULTRY SCIENCE ASSOC INC

Lugar: Champaign; Año: 2019 vol. 96 p. 2608 - 2614

0032-5791

Lettuce (Lactuca sativa L.) constitutesone the most important vegetable crops worldwide.Poultry litter is being applied as an economically suitablealternative to nitrogen fertilizers in lettuce cultivation.However, little is known about the effects ofthis practice over this fresh product safety that is usuallyconsumed as a salad. The aim of this work was todetermine the microbiological quality and the nitratecontent in lettuce produced, under field conditions, usingeither raw or composted poultry litter, coming fromthe same original batch. Two experiments were conductedin the experimental field of Facultad de CienciasAgrarias (UNL, Santa Fe, Argentina) to assess the effectsof recently extracted poultry litter that consistedof broiler chicken manure plus rice husk, or compostedfor 12 mo. The application amounts were: 20 T ha−1(T1); 40 T ha−1 (T2); and no application of manure (T).Increasing the applied quantities had also increased thehealth risk associated with lettuce consumption, dueto higher nitrate levels and microbial contamination.However, these risks were reduced by composting thematerial. Even when lettuce contamination with faecalbacteria was mainly due to the use of poultry litter, thenumber and incidence of pathogens were reduced whenproperly composted manure was applied instead of rawone. Increasing the dose of poultry litter applied alsoincreases the health risk in lettuce. Though, when thematerial is properly composted, its fertilizing capacityis maintained, giving proper yields with lower nitratelevels and microbial contamination by enterobacteria.