Salmonella sometimes with animal disease) and subsequent excretion in the environment; these zoonotic pathogens can be exchanged between animals and the environment and can be spread to the fields by contaminated irrigation water and manure. Listeria monocytogenes contamination can also circulate in the environment without animal infection or carriage. Control of these microbiological hazards can be based on i) the knowledge of the animal status concerning disease and carriage of zoonotic pathogens; ii) the analysis of well dedicated samples to follow the status at selected points of attention during farm production; and iii) a strict implementation of the best practices and hygiene rules during cultivation, harvest and processing. In the short food supply chain the activity of agricultural production and further processing are often combined on the same site and/or managed by the same person in charge. Packing, sorting or processing usually takes place at the farm, using most of the time on‐site harvested crops, raw milk or raw meat derived from own livestock or from agricultural products derived in close proximity. As such, adherence to GAP and control of its raw materials for microbiological hazards is expected to be an inherent central focus point of the short food supply chain. A reduced risk for the introduction of certain emerging microbiological hazards is expected for the short food supply chain production due to its in general local sourcing of inputs (raw and auxiliary materials, feed) in comparison with the globalized food production. ON‐SITE PROCESSING AND DISTRIBUTION OF FRESHLY HARVESTED AGRICULTURAL PRODUCTS In the short food supply chain it is in terms of logistics more feasible to maintain a short and direct link between primary production (harvest, milking, slaughter) and subsequent need of storage until food processing and the distribution to the consumer. In general, this short time frame of storage can be considered as beneficial for the microbiological quality and safety of the end product. This can be deduced from the following examples: 1. Prolonged storage of primary food products at low temperature before processing allows the outgrowth of Gram‐negative psychrotrophic and psychrophilic microorganisms such as Pseudomonas in raw milk. Some Pseudomonas bacteria are capable of producing thermo‐resistant extracellular proteases and lipases, which can cause spoilage and structural defects in pasteurized and ultra‐high‐temperature‐treated milk (products). Outgrowth of Pseudomonas members occurs from the beginning of the dairy chain (farm tank) till the heating process in the dairy industry and is clearly dependent on the storage time (De Jonghe et al., 2011). On‐farm production does not need long storage of raw food products. 34
2. Scientific studies show that the best way of protecting human infection from salmonellosis caused by contaminated eggs is offered by limiting the bacterial outgrowth by direct and constant cooling of the eggs after lay (De Reu, 2006a; Messens et al., 2006). This would be easier to organize in the short food supply chain. In addition, the absence of temperature fluctuations, which may occur more in long food supply chains with multiple transactions, avoids eggshell condensation and thus also bacterial eggshell penetration (De Reu et al., 2006b). The immediate cooling of eggs has been recommended to be included in the Guides for the autocontrol system for activities as the collective nursery (chréche) for young childeren (Sci Com Advice 21‐2011), and the horeca sector (Sci Com Advice 02‐ 2006). 3. Patulin is a mycotoxin, produced as secondary metabolite by several fungal species from which Penicillium expansum is the most important one on apples. Patulin production occurs during storage of damaged apples and patulin contaminates the processed products as apple juice and apple compote (de Souza Sant‐Ana et al., 2008). Reducing the storage time of apples offers the possibility to control the problem. CONTAMINATION FROM DIFFERENT MICROBIOLOGICAL SOURCES MAY BE MORE LIMITED In most cases, the short food supply chain limits processing to the agricultural products produced at the farm; this in contrary to most conventional processing units where raw materials of multiple producers are entering the same processing plant. It is expected that in the short food supply chain, the contamination of the processing area with a pathogen would be limited to those strains circulating on the own farm and its environment. Potential contamination sources can thus be more limited. This would also favor the strength of any epidemiological link in case of human foodborne illness reported and traced back to a contaminated farm product. The same may apply to the microbiological quality of short chain food products. It was for example observed in simulations of the cooled raw milk chain from the farm bulk tank to the dairy plant silo that the overall Pseudomonas diversity was less in a cool stored sample of a single farm milk tank compared to a cool stored mixed sample from different farm milk tanks (De Jonghe et al., 2011). This may have consequences for raw milk quality in processing, shelf life and safety, but more research is needed to have consistent proof of these assumptions. FOODSAFETY CULTURE AND INFORMAL SYSTEMS CONTROLLING ADHERENCE TO BEST PRACTICES Short food supply chains are responding to a consumer demand for a larger variety of “quality” food products. Producers and consumers in the short food supply chain are concerned on values as taste, nutrition, freshness and in 35
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