Meat Quality Issues Discussed at Kansas Conference

Needle-free jet injection systems may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork processing plants, according to one paper presented at Kansas Swine Day 2009, and another revealed that glycerol and ractopamine (singly or combined) had no significant effects on the quality of pork loin chops.
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Pros and Cons of Needle-Free Injection Studied

In the Meat Quality Research session of the latest Kansas Swine Day, B.M. Gerlach presented a paper on the incidence and severity of Arcanobacterium pyogenes injection site abscesses following conventional needle or needle-free injection. They found that although needle-free injection eliminates the risk of broken needles in the carcass and meat, the method was associated with many more abscesses, which will require trimming in the processing plant.

The Kansas University group used a total of 198 nursery-age pigs were used to evaluate the difference in the occurrence of injection site abscesses between needle-free jet injection and conventional needle-and-syringe injection systems.

Pigs were fed for 21 days prior to treatment administration to acclimatise the pigs to the environment of the Kansas State University Segregated Early Weaning Unit. On day 21, each pig received four injections of aluminium hydroxide adjuvant: one in the neck and one in the ham by needle-free jet injection (Pulse Needle-Free Systems, Lenexa, Kansas) on one side, and one in the neck and one in the ham on the opposite side by conventional needle-and-syringe injection. Immediately prior to injection, the external surface of the injection sites was contaminated with an inoculum of Arcanobacterium pyogenes. (A. pyogenes is the most common bacteria found in infected wounds and abscesses.)

The pigs were then fed for a period of 27 and 28 days. On days 27 and 28, the pigs were humanely euthanised and sent to the Kansas State University Veterinary Diagnostics Laboratory, where necropsies were performed and the injection sites underwent histopathological evaluation.

The needle-free jet injection system was associated with more injection site abscesses than the conventional needle-and-syringe injection method for both the neck (P=0.06) and ham (P=0.03) injection sites. Twelve abscesses were found at needle-free injection sites, whereas only one abscess was found where a conventional needle injection method was used.

Five abscesses were found at the neck injection sites, and eight abscesses were observed at the ham injection sites. Of the 13 abscesses found, 10 developed on the left side of the animal, and only three were on the right side.

Gerlach and co-authors concluded that the implementation of needle-free jet injection systems in market hog production will be beneficial by eliminating the potential for needles and needle fragments in meat products, but it may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork processing plants.

Glycerol and Ractopamine Do Not Affect Meat Sensory Characteristics

In the same session, A.W. Duttlinger and co-authors presented a paper indicating that neither glycerol nor ractopamine nor their combination affected the sensory characteristics of pork loin meat.

They evaluated the sensory characteristics of a total of 80 loins from pigs fed diets containing glycerol, ractopamine HCl (RAC) or a combination of glycerol and RAC during the last 28 days prior to slaughter.

A total of 1,054 pigs were blocked by weight and randomly allotted to one of four dietary treatments with 10 replications per treatment. Pigs were fed corn-soybean meal-based diets. Dietary treatments were arranged in a 2×2 factorial design with main effects of glycerol (0 or five per cent) and RAC (0 or 6.75 g/ton).

Pork loins from one randomly selected barrow and gilt from each pen were used for sensory analysis.

There were no glycerol × RAC interactions or main treatment effects for cooking loss or Warner-Bratzler shear force (WBSF).

Additionally, there were no glycerol × RAC interactions or main treatment effects for the sensory traits including myofibrillar tenderness, overall tenderness, pork flavour intensity or off-flavour intensity.

There was a glycerol × RAC interaction (P<0.01) for the sensory trait of connective tissue amount. The interaction was a result of increased connective tissue amounts when glycerol was added to the diet without RAC but numerically decreased amounts when glycerol was fed in combination with RAC.

Feeding dietary glycerol or RAC, singularly or in combination, for 28 days prior to slaughter did not influence sensory characteristics of centre-cut pork loin chops, concluded Duttlinger and co-authors.


Duttlinger A.W., T.A. Houser, J.M. DeRouchey, M.D. Tokach, S.S. Dritz, J.L. Nelssen, R.D. Goodband, K.J. Prusa and L. Huskey. 2009. Sensory Characteristics of Loins from Pigs Fed Glycerol and Ractopamine HCl During the Last 28 Days of Finishing. Proceedings of the Kansas Swine Day 2009, 274-279.

Gerlach B.M., T.A. Houser, L.C. Hollis, M.D. Tokach, J.C. Nietfeld, J.J. Higgins, G.A. Anderson and B.L. Goehring. 2009. Incidence and Severity of Arcanobacterium pyogenes Injection Site Abscesses with Needle or Needle-Free Injection Methods. Proceedings of the Kansas Swine Day 2009, 270-273.

Further Reading

- You can view the full papers by clicking here.

Further Reading

- You can find other papers presented at the Kansas Swine Day 2009 by clicking here.

May 2010
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