Table 12.

Sources of uncertainty associated with the AQs and their possible impact on the conclusions

Source of uncertainty	Cause of the uncertainty	Impact of the uncertainty on the conclusions
Ascertainment of the standard processes for hides and skins	The treatments applied to hides and skins for three of the four types of products declared end points were ascertained by searching in the scientific literature and from industry information in grey literature. The steps and conditions of the treatments could vary except for the lime hides which are specified in the legislation	If the actual treatments applied for the production of pickled pelts, wet blues and tanned hides and skins are different than those described in Section 3, this could result in the higher or lower inactivation of the indicator microorganisms and biological hazards. Including pretreatment may result in greater inactivation
Treatment of hides and skins before processing	The hides and skins before going into tanning must be treated according to Commission Regulation (EU) No 142/2011, which means they are (a) dried; (b) dry‐salted or wet‐salted for a period of at least 14 days before dispatch; (c) salted for a period of at least 7 days in sea salt with the addition of 2% of sodium carbonate; (d) dried for a period of at least 42 days at a temperature of at least 20°C; or (e) subject to a preservation process other than tanning. The potential reduction of indicator microorganisms during this treatment has not been considered	It is expected that some level of reduction will occur due to the treatment of hides and skins, resulting in a higher reduction of the indicator microorganisms in the entire process (treatment and processing of the four conditions for the declaration of end points)
Standard or alternative methods for the production of derived products using Category 3 materials	The methods to be applied to Category 3 materials in the pre‐processing of fat for the production of biodiesel and renewable fuels range from Method 1 to Method 7, which have very different parameters in terms of temperature and time combinations. Method 7 requires microbiological criteria ensuring the absence of Salmonella and Clostridium perfringens, and certain level of Enterococcus spp. Method 5 is the least stringent in terms of temperature of those with explicit parameters in terms of temperature, while Method 6 only applies to aquatic animals/aquatic invertebrates. It was decided to apply as worst‐case scenario the least stringent method in terms of temperature (i.e. Method 5)	Depending on the method applied to the raw Category 3 material, the inactivation of the indicator microorganisms in the raw material could be higher than the estimated inactivation on the basis of the conditions given for Method 5, except for Method 7, which could result in a higher or lower inactivation level
Ascertainment of the transformation processes for the declaration of the end points for wool and hair	Commission Regulation (EU) No 142/2011 does not identify specific technical parameters for the declaration of the end point for wool and hair, and the information retrieved from the literature on the processing of these ABP was scarce. Based on the background information two scenarios were selected to be assessed (pH > 12, 5 min; pH > 12, 60 min). There is the possibility that these two scenarios do not fully reflect current industrial practices	This may result in an over‐ or underestimation of the level of hazard reduction achieved
Ascertainment of the processes for pig bristles	Commission Regulation (EU) 142/2011 does not identify specific technical parameters for the declaration of the end point of pig bristles, and the information retrieved from the literature on the processing of these ABP materials was scarce. Based on the background information, two scenarios were selected for being assessed (boiling at 100°C for 5 or 60 min). There is the possibility that these two scenarios do not fully reflect current industrial practices	This may result in an over‐ or underestimation of the level of hazard reduction achieved
Nature of the chemical processes	Some of the processes under assessment based on chemical inactivation (e.g. liming) are exothermic processes which release heat causing a progressive increase in temperature in an uncontrolled manner. Therefore, the inactivation level attained in these processes may derive from combined thermo‐chemical effects	This may result in the overestimation of the level of inactivation of indicator microorganisms achieved by the chemical processes alone, due to the combination of both thermal and chemical effects
Identification of viral hazards	The viral hazards that may occur in the ABP listed in the mandate were identified through literature searches using search strings, as described in the data and methodologies section. There is the possibility that some relevant reference was not identified or considered. It is also possible that the occurrence of virus in general, or certain families, in particular, have never been investigated	As a result, it could be the case that some relevant virus was overlooked. This could impact on the conclusions only if some relevant heat‐ or chemical‐resistant virus (e.g. non‐enveloped viruses) was overlooked
Inactivation data	Relevant references for extraction of data on thermal and chemical reduction/inactivation of indicator microorganisms were identified through literature searches using search strings, as described in the data and methodologies section. There is the possibility that some relevant reference was not identified or considered for data extraction	This source of uncertainty could lead to either higher or lower inactivation of indicator microorganisms
Inactivation data	The data extracted on thermal and chemical reduction/inactivation of indicator microorganisms were sourced from experimental studies using different matrices to those included in the mandate. There are no specific data available from studies involving spiking the materials included in the mandate with the indicator microorganisms of interest. The different composition in terms of dry matter (total solid contents, aw), fat content, etc. determines the capacity of bacteria, viruses and parasites to survive under different conditions of temperature, time and pH	The capacity of the standard processes to achieve the targeted reductions may be higher or lower than estimated in the materials included in the mandate. In general, the materials have a low water content, while most inactivation data retrieved from the literature derive from studies using liquid media or foods. As microbial inactivation by heat and chemical processes is lower in systems with low water activity, estimations from studies on liquid media or on foods with high water activity could result in an overestimation of the inactivation of the group of materials included in the mandate by the transformation processes
Inactivation data	The data extracted on thermal and chemical reduction/inactivation of indicator microorganisms were sourced from experimental studies using particular strains/isolates of the relevant hazards and different analytical methods, which, for viral hazards, are not standardised. It is uncertain whether they are representative of the behaviour of the whole species	This source of uncertainty could lead to either higher or lower inactivation of the viral hazards
Inactivation data	The data retrieved on thermal inactivation of indicator microorganisms contained information on certain heating temperatures, that in some cases were far from the temperatures under assessment. An extrapolation to temperatures much higher than those used to calculate D‐ and Z‐values might not be accurate. The data extracted on chemical reduction/inactivation of indicator microorganisms were sourced from experimental studies using pH values and concentrations of agents in most cases different from those of the processing methods under assessment, and it is not possible from the available data to calculate equivalent inactivation levels at different pH values and concentrations of agents	This source of uncertainty could lead to either higher or lower inactivation predicted for the indicator microorganisms
Inactivation data	Some of the references retrieved lacked details on the initial load and/or the level of inactivation of the hazard. The data extracted were expressed as presented by the authors without any quantitative presentation or inclusion in the corresponding graph	This could lead to an under‐ or overestimation of the level of reduction achieved by the treatments described in those papers