The effects of onfarm preharvest magnesium supplementation and stunning method on pork muscle qualit

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The effects of on-farm pre-harvest magnesium
supplementation and stunning method on pork
muscle quality D. J. Hanson, E. van Heugten,
M. T. See North Carolina State University,
Department of Food Science Department of Animal
ScienceRaleigh, NC 27695 USA
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• A System for Assuring Pork Quality
• National Pork Board, 2002
• Quality Control Point 2
• Nutritional Inputs
• Magnesium aspartate reduced drip loss and
  improved color and pH
• (DSouza et al., 1998)
• Inorganic sources of Mg in the diet have also
  shown to reduce drip loss, improve color and
  reduce the incidence of PSE
• Magnesium sulfate and magnesium chloride
• (DSouza et al., 1999)
• Magnesium mica (Apple et al., 2000)

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• A System for Assuring Pork Quality
• National Pork Board, 2002
• Quality Control Point 2
• Nutritional Inputs
• Magnesium supplementation via drinking water was
  evaluated (Frederick et al., 2004)
• Supplementation did not affect 45 minute or
  ultimate pH
• Supplementation did not affect L, a, b values
• Supplementation reduced drip loss in the
  longissimus dorsi after 8 days of retail display
• Supplementation reduced lipid oxidation formation
  during retail storage

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• A System for Assuring Pork Quality
• National Pork Board, 2002
• Quality Control Point 6
• Stun Early Postmortem Handling
• Electrical Stunning (ES)
• Packers experience broken backs, bruising, blood
  splash, and meat quality defects related to
  strong muscle contractions upon
  stunning. (Simmons, 1998)
• Carbon Dioxide Stunning (CS)
• Silveira et al., (1998) and Channon et al.,
  (2002) reported positive effects of CO2 stunning
  on pork quality compared to electrical.

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Study Objectives

• To determine the effects of
• pre-harvest magnesium supplementation stunning
  method on
• longissimus dorsi (LD) semitendinosus (SM) pork
  muscle quality.

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Materials and Methods

• Magnesium sulfate heptahydrate was supplemented
  via water 2 days before harvest at a 300 ppm
  level
• n36 barrows and gilts were randomly selected for
  the trial
• n16 pigs were harvested utilizing electrical
  stunning technology (ES)
• n20 pigs were harvested utilizing carbon dioxide
  stunning technology (CS)

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Materials and Methods

• Preharvest handling was kept similar as possible
• Meat was shipped under refrigeration to the NCSU
  Processed Meat Laboratory for further analysis
• Measurements included blood serum Mg level, LD
  and SM ultimate pH, objective color measurements,
  drip loss, and retail display purge loss

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Results

• Pre-harvest on-farm Mg supplementation had no
  effect on pork quality parameters in LD or SM
  muscle samples

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Table 1. Effects of stunning method on carcass
characteristics, UpH and serum Mg
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Figure 1 Percentage purge loss for pork
longissimus chops over 8 day retail display
P0.04

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Figure 2 Percentage purge loss for pork
semitendinosus muscle over 8 day retail display
P0.02
Pgt0.01
Pgt0.01

Pgt0.01
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Table 2. Effects of stunning method on L
values of pork longissimus dorsi chops during
simulated retail display
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Table 3. Effects of stunning method on a
values of pork longissimus dorsi chops during
simulated retail display
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Table 4. Effects of stunning method on L
values of pork semitendinosus muscle during
simulated retail display
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Table 5. Effects of stunning method on a
values of pork semitendinosus muscle during
simulated retail display
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Table 6. Effects of stunning method on b values
of pork semitendinosus muscleduring simulated
retail display
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Conclusions

• Mg supplementation before harvest did not improve
  pork muscle quality
• LD ultimate pH was not affected by stunning
  method
• SM ultimate pH was higher in the CS group
  compared to samples from the ES treatment

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Conclusions

• CS treatment appears to be reduce drip loss
  during retail display of LM and SM
• CS has a positive effect on pork color during
  over retail display
• Improvements in pork muscle quality of the LD and
  SM were observed in the plant utilizing CS as
  compared to the plant utilizing ES

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