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Results and Discussion
The questionnaire developed for the field and warehouse is based on information from scientific literature as well as on the samplers’ own experience. It is also based on the growth of microorganisms along the entire food chain. It is well known that pre- and post-harvest environments are significant sources of pathogens.
Questions and answers are divided into two weighted categories: high-risk questions (HRQ) and low-risk questions (LRQ), as well as additional information on the conditions of the work. The number of “Yes” and “No” votes are summarized separately and taken for a decision on microbiological sampling.
Salmonella, Shigella, and E. coli O157:H7 and other pathogens that can survive for extended periods of time in water. Flood and spray irrigation represent the greatest risk because contamination can be directly deposited onto edible parts of produce. Reconstituted pesticides may also serve as potential sources of pathogens.
LQR collects and evaluates marginal conditions for microbiological contaminations that could be a risk when a common occurrence. The choice of questions was based on respective regulations:
- Regulation (EC) No. 2073/2005 on microbiological criteria for foodstuffs;
- Regulation (EC) No. 1935/2004 on materials and articles intended to come into contact with food; and
- Guidance for dealing with fruits, vegetables, potatoes.
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Additionally, a monitoring process is included that evaluates the minimum hygiene standards in the field.
The questions should be answered by growers, agricultural technicians, engineers and experienced samplers with “yes,” “no,” or “not known.” Objective criteria is defined to enable correct answering of questions.
The action plan. In case of a positive finding, the main problem often is the absence of an effective plan to restore microbiological safety. The laboratory that has detected the pathogens is responsible for forwarding information to the corresponding grower/producer and to the whole supply chain via the trader. A second sample has to be stored for cross-checking. The laboratory is also responsible for source identification as well as the magnitude of microbiological contamination in the field or warehouse of the grower/producer. The trader has to ensure the grower and all affected goods in the supply chain are temporarily blocked from the market. The trader also contributes to restoring the delivery capacity of the grower.
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The control plan. In case of a detected risk, a microbiological sampling takes place according to the rules of the Questionnaire for Microbiological Risk Assessment (QMRA). A microbiological sample consists of a number of individual subsamples. Each individual subsample is transported and analyzed separately. If any of the subsamples contain pathogens, harvesting is forbidden on the field of origin. A special controlling plan is implemented to identify the source and to decide if point source or nonpoint source contamination exists. Using GPS coordinates and other markers, the affected field is divided into five different, clearly separated areas that adjoin the area where the original sample was found. Control samples from the crop, the soil and the irrigation water have to be taken from each subarea and analyzed to measure the extent of contamination. A nonpoint source contamination exists if two or more control samples are positive. If only one sample is positive a partial contamination of the corresponding subarea exists. A point source contamination exists if all control samples are negative. This implies that only a part of the original sample was contaminated and that contamination could not be detected again. To detect and permanently address the source of microbiological contamination, further microbiological samples from irrigation water and soil must be taken, especially in cases where the same water or fertilizer is used for the subareas.
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