By Carraig Paterson, technical manager, Enterprise Pork Packers
Colour of pork in fresh and processed meat products is critical for the consumer. Their purchase is based on product quality, value, appeal and product quality knowledge. Product appearance (meat colour) is what draws the consumer to purchase a product that has eye appeal. Consistent pork meat colour is affected by a web of multi-factorial actions that occur in the pork production chain.The intention of this article is to focus on critical steps that could impact on pork meat colour from a manufacturer’s perspective. Pale, soft & exudative (PSE) pork has been identified as a major contributor to inconsistent pork meat colour and attention will be drawn to these factors. The occurrence of PSE pork in the meat industry is very high (up to 55% observed) and tremendous financial losses would be incurred by producers if they were to be paid less for carcasses which develop PSE pork, resulting in lower carcass mass, poorer product yields, and product rejection at factory and retail level due to poor and inconsistent product colour.
Carcasses of pigs with the recessive MH-gene (malignant hyperthermia), either in the heterozygous Nn form, or in the homozygous nn form are associated with leanness, large eye muscle area, higher ham yield and better carcass conformation. However, their carcasses and meat have detrimental financial characteristics. The costs of this gene to manufacturers are prohibitively high and impacts on the quality characteristics of carcasses as produced at abattoirs, the quality characteristics of meat retail cuts and the quality characteristics of processed meat products.
The inclusion of higher levels of Vitamin E, selenium, magnesium and conjugated linoleic acid in finisher and/or grower rations of pigs, prior to marketing is critical. Although costly for the producer, the improvement in achieving consistent pork meat colour would add value to pork’s appearance and could improve pork consumption.
Calm handling of pigs during on-loading, transport and off-loading minimises pig injuries and reduces bruising. Bruised portions of carcasses need to be trimmed away during dressing, resulting in a decreased mass of saleable carcass meat. If bruised portions are processed into hams, consumers often reject the ham slices.
The excitement of pigs immediately prior to slaughter leads to their meat being pale, soft and exudative resulting in greater drip loss, cooking loss and paler colour – even two tonedness.
Truck loading density, time on the truck, air circulation, condition of the truck floors and walls all impact on pork meat quality. Truck standing time at abattoir is critical. The use of shade cloth on the top deck prevents sunburn, reduces dead on arrivals (DOA) and decreases the severity of PSE pork.
Housing at the abattoir
Housing of pigs in large pens must be comfortable and as calm as possible. Mist sprays for cooling in summer; balls for playing in pens and music have a calming effect and help to keep noises down. Mixing of boars and gilts in the same pens increases vocalisation levels and fighting.
Calm handling of pigs on their way to the stunning area is critical. Pig stunning must ensure the full unconsciousness of the pig prior to sticking. The stunning and sticking time should not exceed 19 seconds. Incorrect stunning dramatically increases the incidence and severity of PSE pork.
Retail cutting and pork deboning
Pork carcasses can be cut and sold either as fresh meat cuts or be used in processed pig or manufactured pork products. Either way, customers have specific requirements regarding the appearance of the product, namely that it should be of uniform pink colour.
PSE meats from loins and hams, and occasionally fillets can be downgraded by the pork processor from the higher valued fresh meat cuts to lower valued meat trimmings only usable for manufacturing.
In one case up to 55% of loins designated for fresh meat and back bacon had to be rejected, due to inconsistent pork meat colour.
It could well be asked if some of these losses should be passed on to pork producers that supplied carcasses which developed PSE meat resulting in poor and inconsistent pork meat colour.
Processing of pork and manufacturing of pork products
Generally, “processing” refers to whole muscle products e.g. sides of bacon, cooked hams which are generally of higher value. “Manufacturing” generally refers to products obtained by amongst other processes, mincing (emulsifying), mixing, cooking and they are generally the lowered valued products. Apart from the lower yield of processed or manufactured products from PSE pork, many such products are discarded or rejected due to their unacceptable colour (two tonedness).
However, a certain number of these products do find their way to selling outlets. Retailer and customer complaints on product appearance and taste are increasing, especially about inconsistent unappealing processed pork meat colour.
To obtain consistent attractive pork meat colour, in both fresh and processed pork products, a multi-industry approach has to be adapted to drive the incidence of PSE pork down for the benefit of both the pork producer and pork processor.
Some pork processing abattoirs like Enterprise Pork Packers, already apply sound principles regarding off-loading, calm treatment, stunning, sticking and dressing of pigs and their carcasses as well as the cutting, processing and manufacturing of pork.
There is generally good agreement between pork packers and pork producers about the effective on-farm loading, transport and off-loading of pigs at abattoirs.
Producers, however, are the ones which can control the frequency of the MH-genes in their herds.