Table B.1.

Qualitative assessment included the ‘sources or location of the uncertainty’, a description of the ‘nature or cause of the uncertainty’ associated with that source and a description of the Impact of the uncertainty on the conclusions

Source or location of the uncertainty	Nature or cause of the uncertainty	Impact of the uncertainty on the conclusions (e.g. over/underestimation)
Defining ‘standard fresh meat’ versus ‘dry‐aged meat’ and ‘wet‐aged meat’	By definition, fresh meat is meat that has not undergone any preserving process other than chilling, freezing or quick‐freezing. The majority of fresh beef, pork and lamb is matured in vacuum packaging under chilled conditions. Wet‐aged meat is meat that has been vacuum packaged and stored under chilled conditions. There is no scientific, commercial or legislative basis for differentiating between the ‘standard fresh meat’ and ‘wet‐aged meat’. Thus for the purposes of this Opinion differentiation is based solely on the time in chilled storage.	A misinterpretation or misunderstanding of what constitutes, ‘standard fresh meat’ versus ‘wet‐aged meat’ could result in an over or underestimation of the predicted growth of pathogenic and/or spoilage bacteria in ToR3, negate the ‘equivalence calculations’ in ToR4 and render any additional GHPs or CCPs in ToR5 redundant.
Inaccurate, incorrect or incomplete information about current practices used by FBOs for dry‐ageing and wet‐ageing beef, pork and/or lamb in the scientific and grey literature. Information for wet‐aged pork and lamb was especially lacking and limited to 3 studies, none of which reported aw values. As none of these were observational studies, the reported values may not be representative.	The scientific literature reports the time, temperature, RH and/or air flow used in experiments and these are selected based on the objective(s) of that study. Thus, these conditions may or may not reflect those used in commercial operations. Moreover, many of the scientific and technical reports are from countries outside of the EU and the conditions used may not be representative to practices within the EU.	This lack of information on commercial practices reduces the certainty that the methods and conditions described in the response to ToR1 are an accurate description of current commercial practices in the EU. If parameters such as surface temperature, pH and aw are incorrect there is uncertainty about the outcomes of the predictive modelling in ToRs 3 and 4.
The limited information about current practices provided by commercial FBOs involved in dry‐ageing beef or wet‐ageing beef, pork or lamb in response to the questionnaire.	As this information was only provided by 8 FBOs and 2 FBO associations data were limited (for example, they do not routinely monitor and record surface temperature, pH and aw) and from a limited number of countries it may not be accurate or a reasonable representative of the entirety of European or regional practices. Moreover, for the dry‐ageing of beef, tradition and personal preference for specific organoleptic qualities in the final product are more important than strictly following a pre‐defined process. Thus, there may be differences in the processes used for different batches.	An underestimation of the temperatures used for modelling could, for example, result in an underestimation of the growth rate of pathogens/spoilage bacteria. However this has been mitigated to some extent by using a range of temperatures.
Information on pathogenic and spoilage bacteria that may be on dry‐aged and wet‐aged meat and how these bacteria will behave in minced meat or MSM prepared the aged meat.	Although several studies have reported and reviewed the prevalence of pathogenic and spoilage bacteria in beef, pork and lamb relatively few have specifically studied dry or wet‐aged meat.	Specific pathogenic or spoilage bacteria may have been erroneously excluded from the answer to ToR2. However, this would have a minimal impact on the conclusions as the range of bacteria including those capable of growth under the conditions encountered were considered.
Information on the hygiene status of the carcass and the time between the end of carcass chilling and the preparation of meat cuts for dry and wet‐ageing.	Few, if any, studies provide this information. Based on the available data, the pre‐ageing time (between slaughter and ageing) may vary considerably and counts at the start of ageing may be highly variable.	The initial microbial counts at the commencement of dry or wet‐ageing may be higher or lower than reported in the few available studies cited in answering ToR2. However, as the assessment deals with log changes this will not impact on the outputs of the simulations using predictive models in ToRs 3 and 4.
The impact of competing microbiota on the predicted growth of L. monocytogenes, Y. enterocolitica and non‐proteolytic Clostridium spp.	The effect of competing microorganisms was not included in the predictive models used for the main assessment, though the impact has been assessed in the framework of the effect of factors on the predictions focusing on the interaction between LAB and L. monocytogenes	This uncertainty has been quantified in the uncertainty analysis and in general results in an overestimation (competing microbiota contributes to inhibit and/or stop pathogen growth). A possible exception is Pseudomonas spp. as some articles report the enhancement of L. monocytogenes growth in presence of pseudomonades. However, others have reported a suppression of L. monocytogenes maximum population density by Pseudomonas at low temperature (4°C, Buchanan and Bagi, 1999).
Determining if mycotoxins are produced by moulds during the dry‐ageing of beef	The specific conditions under which moulds, specifically Penicillium and Aspergillus spp. will not produce these toxins are based on a limited number (4) of studies, 3 of which focused on plant based foods. These conditions are not defined for meat and/or no specific studies have been undertaken during the dry‐ageing of beef.	It is not possible to definitively state whether or not mycotoxins are produced during the dry‐ageing of beef, even when this process is well described, although our current knowledge would suggest mycotoxin production is inhibited at temperatures below 3°C and at the aw values encountered.
Simulation of microbial growth ‐ lag phase	No lag phase was considered for any relevant microorganism assessed for the main assessment.	An overestimation of the potential growth can occur when no lag phase is included (conservative approach). However, if contamination is already present at slaughter, microorganisms can adapt to the environmental conditions during the pre‐ageing time. In this case, the impact of this uncertainty in ToR3 and ToR4 is considered to be limited/low.
Simulation of microbial growth ‐ inactivation	Only growth rate models were used in the assessment. No inactivation was considered for any relevant microorganism assessed for the main assessment, though the impact of this factor has been assessed in the framework of uncertainty analysis (Section 3.4.4.1).	An overestimation of the growth can occur when no inactivation is included (conservative approach). This is especially relevant during dry‐ageing and the impact was evaluated and considered in the response to ToR4.
Simulation of microbial growth ‐ calibration factors for predictive models	Observed growth rates from the collected experiments were estimated by fitting the primary growth model to data from challenge test (pathogens) or naturally contaminated means (spoilage). Depending on the design of the experiment and the available data the model fitting will be more or less robust. Predicted growth rates had to be obtained by assuming the input value for aw and for endogenous lactic acid concentration (if considered). For vacuum‐packaged meat, several scientific articles report no growth at all of L. monocytogenes. The growth model will represent the worst‐case scenario For dry‐ageing, the calibration factors have been obtained comparing growth data at high aw. The same behaviour was assumed for the entire range of aw occurring during dry‐ageing.	Over‐ or underestimation of the Bf can over‐ or underestimate growth predictions in ToR3 and ToR4.
The additional actions required in the PRP and HACCP programmes to assure the food safety of dry‐aged beef.	There is a lack of information on the specific GHPs currently used in the meat ageing processes as these are rarely studied and seldom reported.	There may be additional GHPs or CCPs used in FBOs that are not reported and therefore unknown outside of those specific food businesses. Thus the response to ToR5 may be inadequate.