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2. Slaughterhouse hygiene problems and solutions

Scope of problems

Many of the APHCA-member countries have at least one good-quality abattoir. However, the quantity of meat produced in them is only a small fraction of the countrywide abattoir output, and the meat produced in those facilities frequently goes to export or to up-market sales outlets. In many of 12 APHCA-member countries there are some new abattoirs in construction currently that are encouraging. On the other hand it is still fact that the bulk of the meat sold within many APHCA-member countries most likely originates from unhygienic slaughtering and meat handling.

This report highlights examples of the current situation and ways to solve these problems. But it does not deal with residues in meat deriving from environmental pollutants, veterinary drugs, growth-promoting agents and illegal preservatives, which might be found in meat. The concern of this report is the excessive microbial contamination of meat that occurs during and after (transporting) routine slaughtering in many Asian countries.

One of the main principles of slaughter hygiene is to avoid contact between a carcass and the floor. The carcass needs to be off the ground as soon as possible during the first steps of the slaughtering process. This requirement is best fulfilled if carcasses are already off the ground at the point of bleeding. In the absence of supporting technical devices to hoist up carcasses for bleeding, that step can be done on the ground because the carcass is still fully covered by the skin. Once the protective cover of the animal skin is cut open or removed, it is absolutely necessary to prevent any contact with the floor.

Unfortunately, such optimal conditions are only the exception and not the rule in many slaughter facilities in APHCA-member countries, similar to the situation in most developing countries. Contact with unclean surfaces is the main source of meat contamination, and floors are among the most contaminated surfaces.

Main problems in small ruminant slaughtering

Slaughtering of sheep and goats is technically easy. Even with simple equipment it can be done in a clean and hygienic manner. The exception are sheep breeds with large amounts of wool, in which a great deal of cross contamination from hair to skin can occur if no proper equipment to assist the skinning process is available, such as a skinning line that suspends the carcass in a horizontal position using the four legs (Fig. 21).

Meat contamination of short-haired species during skinning and eviscerating usually can be kept minimal if simple equipment for carcass suspension is available, such as wall hooks or racks with hooks (in small operations) or hooks or gambrels attached to an overhead rail in larger operations (Fig. 16, Annex A5).

Hygienic problems in slaughterhouses for small ruminants are mainly caused by the absence of a carcass suspension system or handling negligence, such as:

Main problems in bovine and large ruminant slaughtering

Severe hygienic problems in the slaughtering of cattle and buffaloes in many places stem from the difficulty in handling these heavy carcasses where there is inadequate or no slaughter equipment available. Proper equipment for handling bovines includes manual or electric hoists for lifting up the carcass – getting it off the floor for flaying, eviscerating and splitting.

In traditional slaughtering, bovine carcasses are placed with the back on the ground. In this position the hide is loosened from the carcass, starting from the hind leg, belly and forelegs. The hide serves as protection of the meat surfaces from direct contact to the ground. Evisceration also takes place in this position. This procedure is the only possible method in rural slaughtering and may work reasonably well, if only one or two animals are slaughtered carefully and without time pressure. As soon as more animals are brought to be slaughtered in the same location, such as at a commercial slaughter slab in which workers are usually under time pressure, heavy bacterial loads on the meat through cross contamination cannot be avoided.

The following photo examples (Figs. 2–7) illustrate extremely heavy meat contamination during large-ruminant slaughtering, dressing and deboning due to ignorance or neglect of the basic rules of hygiene. Such practices, which are a threat to food safety and consumers’ health, are unfortunately very common in APHCA-member countries.

Figs. 2 and 3 show cattle slaughtering entirely carried out on the ground, in many cases followed by carcass splitting, cutting and deboning on the same contaminated floor area. Bovine slaughtering on the floor is a major source of meat contamination. But doing the cutting and deboning there as well multiplies the bacterial load introduced into the meat. The newly created meat surfaces (from the cutting and deboning) become massively contaminated; due to the microbial lag phase (Fig. 1), rapid spoilage will normally not occur within the first few hours. Any prolonged storage under ambient temperatures will boost rapid spoilage. Moreover, there is also the high risk of contamination with food poisoning micro-organisms, such as Salmonella and enterohaemorrhagic E. coli (EHEC), which should be taken very seriously. EHEC infections of humans can occur with relatively low bacterial numbers of the relevant type of E. coli.

Fig. 2: Roadside cattle slaughtering:This method used to be the only source of beef in this particular country.

 

 

Fig. 3: Buffalo slaughtering on a slab: Slaughtering and carcass deboning is carried out with only a knife and axe on the ground, which is heavily contaminated with animal manure, intestinal content and dirty water. Buffalo dung lays in close proximity to the meat being deboned on the ground. This kind of slaughtering operation is the only source of meat for shops in the city where it is located.

 

 

Fig. 4: Restraining buffalo for bleeding on the ground: This takes place amid dressed carcasses and deboned meat on the same ground.

 

 

Fig. 5: Evisceration of buffalo carcass on the ground next to carcass parts of other animals

 

Fig. 6: Complete deboning of entire carcass: The process takes place on the same spot previously contaminated from the slaughtering of another animal.

 

Fig. 7: Meat contamination by flies

Even when simple hoisting equipment is available, the hygienic benefits of lifting a carcass off the ground are frequently spoiled by malpractices of butchers, such as by the lowering of the suspended carcass so that the neck and forequarter touch the floor. This lowering is done to minimize movements of the hanging carcass and to stabilize it with the floor contact for eviscerating and splitting (Figs. 8 and 9).

Fig. 8: Floor contact of forequarter during carcass splitting

 


Fig. 9: Meat of heavily contaminated forequarter with microbial spoilage after short period of unrefrigerated storage

Often, in the case of using hoists for relatively hygienic flaying, eviscerating and carcass splitting, the forequarters or even both fore and hindquarters are dropped to the floor after separating them from the suspended carcass sides. All efforts at having slaughtered and dressed the carcass hygienically are thus spoiled (Fig. 10).

 

Fig. 10: Dropping of forequarters on the floor after separating them from the carcass as it hangs on a rail

Main problems in pig slaughtering

Pig slaughtering is much easier than cattle or buffalo slaughtering because the carcass is not very voluminous. But it is still heavy enough to require equipment for lifting and suspending. Also, the pig skin is typically not removed because it is eaten along with the meat. With that protective covering in tact during the slaughtering, less of the meat surface is exposed and thus not subjected to easy contamination.

But contamination can occur during the removal of hair from the skin, which is done by scalding the carcass in hot water tanks. Two problems can arise in this process:

Pig slaughterhouse operators must be forced to keep the carcasses and the meat off the ground, starting with the scalding process. This can be done in the small- to medium-sized facilities with moderate investment (see pages 30-32). The solutions proposed in Figs. 49 and 50 in this report are absolutely adequate as long as such slaughter operations produce for the traditional “wet” (open-air, or fresh) meat markets. With some modifications, they also can be considered for more demanding chilled-meat production.

Tremendous hygiene problems with heavy meat contamination can occur if the entire pig-slaughter operation is carried out on the ground (Figs. 12–15), which is still the case in many pig-butchering facilities in APHCA-member countries.

Fig. 11: Traditional scalding vat: The vat is heated by fuel wood, which does not allow for temperature control. Only a small quantity of scalding water is available.

 

 

 

Fig. 12: Unhygienic slaughtering of a pig on the floor: One of the butchers steps on the carcass for assistance in opening it for evisceration.

 

Fig. 13: Carcass splitting on the floor

 

 

 

Fig. 14: Carcass cutting on the floor

 

 

Fig. 15: No separation of live pigs: Carcasses being dressed and meat being cut and deboned all in the same area.

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