Aitchbone hanging or moisture infusion, but not ageing, influenced eating quality of pork cuts

The Australian pork industry is working to develop a cuts-based, non-prescriptive eating quality system for pork. Channon et al. (2011) identified that as the majority of studies have utilised the loin muscle, more data is needed to quantify the impact of different production and processing factors, as well as cooking methods, on eating quality of different pork cuts. For this system to be non-prescriptive, different supply chains need to have flexibility in determining which pathway interventions may be implemented to deliver high quality pork to consumers. This study aimed to validate the effect of hanging method, ageing period, moisture infusion, cut and cooking method, and their interactions, on eating quality attributes of pork from female (F) and entire male pigs immunised against gonadotrophin releasing factor (GnRF) (IM) pigs. It was hypothesised that pork eating quality can be improved to result in a fail rate of less than 10% by the implementation of a combination of pathway factors known to influence eating quality.

Large White x [Landrace x (Duroc x Large White)] entire male and female pigs (n = 36 per gender) were managed on-farm, within gender, until slaughter at 22 weeks of age. All males were immunised against GnRF using Improvac^® (Zoetis Ltd, USA), with the vaccine administered at 10 and 17 weeks of age. A total of 25 pigs per gender was selected from the larger group based on carcase specifications (60–75 kg Trim 1; P2 8–13 mm) at 60 min after slaughter and carcases were randomly allocated to hanging method [Achilles (AH), or aitchbone (ABH)]. Within hanging treatment, sides were randomly allocated to ageing period (2 or 7 days). Moisture infusion was only applied to AH 2 day aged cuts at a rate of either 0% (no-MI) or 10% brine solution (MI)). Cut x cooking treatments used and fail rate was determined as described by Channon et al. (2015). Consumers (n = 400) rated 2,000 samples for overall liking (OL) (0 – dislike extremely to 100 – like extremely). Data were analysed by ANOVA.

Ageing for 7 days did not improve (P > 0.05) OL scores and pork from IM and F carcases was comparable for eating quality (data not presented). For OL, interactions between hanging method and between MI and hanging method were observed within cut (Table 1). Within each cut type, ABH improved OL scores for loin stir fry (P = 0.004) and roast (P = 0.028) and silverside stir fry (P = 0.005) compared with AH, indicating positive opportunities to improve pork eating quality. Across all cuts, ABH reduced fail rates by 9.6% compared with AH. The OL scores were improved (P < 0.05) by MI, compared with all non-MI cuts obtained from AH and ABH carcases (except ABH silverside stir fry). Across all treatments, only MI loin stir fry, roasts and steaks and ABH loin stir fry achieved fail rates of <10% (data not presented). Significant challenges to both identify and commercially implement cut-based strategies that reduce the fail rate of pork cuts to <10%, in addition to MI, remain. Given that ageing for 6 to 10 days after slaughter has a positive effect on eating quality (Ngapo and Gariepy 2008), further work to understand why ageing was not an effective intervention for pork in this supply chain is needed.

Table 1.  Hanging method and moisture infusion (none or 10% infusion) effects on fail rate (%) and overall liking scores ^A of five pork cut x cooking treatments