Distribución

At abattoir level, the primary goal is the risk reduction for the main hazards that can be achieved through integrated programmes based on good manufacturing practices (GMP)/ good hygiene practices (GHP) and HACCP, including:

control of feed withdrawal times in order to reduce defecation during transportation, to reduce faecal shedding during defeathering and to facilitate evisceration during slaughter (EFSA, 2011a)

logistic slaughter based on the risk categorisation of the slaughtered flocks; this could be slaughter of higher risk flocks at the end of the day, on special days (at the end of the week), at separate slaughter lines or even at different abattoirs

hygienic practices and technology-based measures aimed at avoiding direct and indirect cross-contamination with the main hazards

interventions such as the scheduling of higher risk flocks for carcass decontamination or for risk-reducing processes such as heat- or freezing-based treatments to reduce loads of pathogenic microorganisms.

Once the targets mentioned in section 4.2 above are set for carcasses, achieving them depends on following: (a) the presence/level of the hazards in incoming birds; and (b) the abattoir process hygiene.

Both these aspects need to be effectively controlled, if the targets are to be achieved in a predictable and reliable manner. The occurrence or level of the main hazards in the incoming birds may be controlled by setting targets in primary production and/or handling birds according to their flock‟s infection status as reported by the FCI. Abattoir process hygiene contribution to achieving targets is primarily through technology- and hygiene-based preventive measures to reduce direct and indirect cross-contamination.

The differentiation of slaughterhouses on their contamination reduction capacity could be a way of sending flocks presenting specific risk levels to adapted slaughter lines or slaughterhouses. For example, high-risk flocks might be directed to a specific category of slaughterhouses having suitable equipment to reduce the contamination of carcasses and to achieve an acceptable risk-reduction/contamination level in the final product.

Collection and analysis of data over time would, in addition, enable continuous monitoring of the abattoirs‟ performance and thereby act as an indicator of the efficiency of the technology- and hygiene-based processes in reducing the final microbial load of the carcasses. Such analyses could indicate whether the abattoirs are improving or whether they might be failing to maintain previously high standards. An assessment of historical data could also be used for adjusting the sampling frequency of the main hazards in order to focus control efforts where the process hygiene does not ensure satisfactory sanitary conditions.

A structured approach to gather more detailed slaughterhouse information related to their equipment and the efficiency of microbial process controls should become an additional element that could form the basis for the risk categorisation of the slaughterhouses.

4.2.2.1. Classification of abattoirs according to technological capacity to control contamination The main hazards identified are carried in the gastrointestinal tract and/or on the feathers of birds presented for slaughter, and carcasses become contaminated due to direct or indirect cross-contamination that is highly dependent on the slaughterhouse technology. Although technical aspects of individual steps of the poultry slaughter line may vary considerably between slaughterhouses, the type and generally the order in which these steps are carried out are less variable and are generally as follows: transport/lairaging – stunning – bleeding – scalding – defeathering/plucking – neck slitting/foot removal – evisceration – washing – chilling (see contractor‟s report¹⁶).

Each of these steps contributes differently to the final microbial load of the carcass. Cross-contamination between flocks and/or individual birds can occur from transport and lairaging and during the slaughter process. Transport crates can be a source of contamination even when they have been disinfected (Berrang et al., 2001; Ellerbroek et al., 2010; Slader et al., 2002). Campylobacter prevalence on chicken carcasses decreases immediately after scalding and chilling, and increases after defeathering and evisceration (Berrang et al., 2001; Guerin et al., 2010; Hue et al., 2010; James et al., 2006; Rasschaert et al., 2006; Rosenquist et al., 2006; Tsola et al., 2008). Primary chilling reduces the numbers and prevalence of pathogenic and spoilage microorganisms on poultry carcasses (James et al., 2006). Freezing carcasses is also an effective intervention to reduce Campylobacter prevalence on carcasses (Rosenquist et al., 2006; Stern and Robach, 2003).

Within each of these steps, a great variety of technical systems exists, and they also contribute differently to the final microbial load of the carcass. The design of the defeathering machine influences the pattern of microbial contamination: the contrarotating machine contributes to a higher contamination of carcasses than the disc machine (Allen et al., 2003). Despite the limited human handling (Tsola et al., 2008), the risk of cross-contamination is increased when the evisceration is fully automatic (Hue et al., 2011). As the machinery cannot adapt itself to the natural variation in size of carcasses within a given batch, rupture of viscera is common and the release of intestinal contents can contaminate the carcasses eviscerated (Hue et al., 2010; Hue et al., 2011; Rosenquist et al., 2006).

Both air chilling and water spray chilling decrease Campylobacter contamination of the carcasses and the reductions obtained are not significantly different (Rosenquist et al., 2006). However, a greater reduction in contamination is observed when immersion chilling is used (James et al., 2006).

Decontamination treatments for carcasses are one way of reducing contamination and can be divided into physical and chemical treatments. Physical interventions include water-based treatments, irradiation, ultrasounds, air chilling or freezing. Hot water, steam, electrolysed water and irradiation effectively reduce the bacterial load. Chemical interventions comprise organic acids and chorine- or phosphate-based treatments. Acetic and lactic acid, acidified sodium chlorite and trisodium phosphate reduce the bacterial load (Loretz et al., 2010). Some combinations of treatments further enhance the reductions (Loretz et al., 2010). However, some of these methods are limited by their practicability, regulatory requirements or acceptability to consumers (ACMSF, 2005). Thus, the best way to achieve reductions in carcass contamination is likely to come either from physical decontamination treatments, or from technological developments in the process that are designed to improve hygiene, as long as they are acceptable to the industry and the consumer.

Each slaughterhouse can be viewed as unique, owing to differences in poultry species slaughtered, logistics, processing practices, plant layout, equipment design and performance, standardised and documented procedures, personnel motivation and management, and other factors. These variations individually and in combination lead to between-slaughterhouse differences in risk-reduction capacities and, consequently, in the microbiological status of the final carcass. A few studies have

A relationship was reported between slaughterhouse operational hygiene inspection scores and Campylobacter contamination in broiler carcasses (Habib et al., 2012). Consequently, a risk categorisation of slaughterhouses is possible, based on the assessment of individual hygiene process performance. For that, a standardised methodology and criteria for assessment of process hygiene is a prerequisite.

4.2.2.2. Process hygiene criteria (PHC) using of E. coli as indicator of faecal contamination

E. coli is a normal inhabitant of the intestinal tract of birds and warm-blooded mammals, and is commonly used as an indicator of faecal contamination and hygienic food handling and processing.

There is a general recognition in the scientific literature that indicator microorganisms are better suited for use in process hygiene assessment than pathogenic microorganisms (Blagojevic et al., 2011;

Bolton et al., 2000; Koutsoumanis and Sofos, 2004). This is principally because pathogens occur in animals/on carcasses at highly variable frequencies. In addition, they are often more difficult to count/quantify and require more laborious handling in better equipped laboratories. Currently, Salmonella is used to demonstrate an acceptable level of contamination as part of PHC, but, for the reasons above, the use of E. coli or Enterobacteriaceae should be considered. Pathogen testing is valuable for the purposes of consumer exposure assessment and pathogen reduction programmes, and for such purposes E. coli cannot replace testing for pathogens as these can still occur on carcasses when levels of indicator organisms are low. However, the presence of generic E. coli at high levels indicates the presence of intestinal material, which is considered to be a measure of slaughter hygiene (Ghafir et al., 2008; Habib et al., 2012; USDA, 1996).

Altekruse et al. (2009) evaluated whether the number of E. coli bacteria in carcass rinses from chicken slaughter establishments could be monitored for the purpose of microbial process control and made conclusions supporting the use of E. coli as a specific indicator of faecal contamination in the context of process hygiene.

A post-chill mean log10 E. coli colony-forming units (CFUs)/ml carcass rinse value of 1.1 provided a useful reference for the design of a process control plan (Griffith, 1996), defining two distinct groups of establishments: those with higher versus those with lower means. This value also suggested a possible tolerance above the mean for the purpose of process control. With additional information confirming expected E. coli numbers during poultry processing, control plans may be developed that define acceptable frequencies of small, medium and large deviations above the process mean (Griffith, 1996) and other quality control measures (e.g. moving averages or the cumulative sum control chart (CUSUM) method, as described by Hayes et al. (1997)).

Some regulatory agencies and food manufacturers have recognised the potential utility of E. coli numbers as a measure of slaughter process control. For example, USDA‟s HACCP rule (USDA, 1996) specifies two criteria for evaluating process control: establishments are to maintain fewer than 100 CFUs/ml of E. coli in 80 % of poultry carcass rinses and never exceed 1 000 CFUs/ml.

Other studies have been performed to define and assess precise E. coli performance criteria for poultry (Ghafir et al., 2008), to monitor microbial reduction during slaughter processing (Gill et al., 2006), and to validate interventions to reduce microbial numbers on poultry (Stopforth et al., 2007).

Most experiences with the use of E. coli as a process hygiene indicator are from the USA, and there are only limited data in the scientific literature on the quantitative levels of E. coli and on poultry carcasses from slaughterhouses in the EU and the usefulness of these as process hygiene criteria.

In the EU, Enterobacteriaceae have also proved to be useful as indicators for process hygiene in other animal species such as pigs and cattle (Arthur et al., 2004; Blagojevic et al., 2011, 2012).

Measuring E. coli or Enterobacteriaceae on poultry carcasses at the end of the slaughter line could, therefore be a means of verifying the efficiency of microbial process controls that are designed to

ensure sanitary conditions on carcasses. It is recommended that the use of E. coli or Enterobacteriaceae for such purposes in poultry meat inspection is further investigated.

4.3. Inspection methods for Salmonella in the integrated system