This article was downloaded by: [University of Wisconsin - Madison] On: 02 February 2015, At: 09:45 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
New Zealand Veterinary Journal Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tnzv20
Bacteriological evaluation of bruised tissue in lamb carcasses G.V. Petersen a
a b
Meat Division , Ministry of Agriculture & Fisheries , P.O. Box 3, Longburn
b
Meat Division , MAF , P.O. Box 198, Feilding Published online: 23 Feb 2011.
To cite this article: G.V. Petersen (1978) Bacteriological evaluation of bruised tissue in lamb carcasses, New Zealand Veterinary Journal, 26:1-2, 9-10, DOI: 10.1080/00480169.1978.34476 To link to this article: http://dx.doi.org/10.1080/00480169.1978.34476
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
1978
9
NEW ZEALAND VETERINARY JOURNAL
Bacteriological evaluation of bruised tissue In lamb carcasses G. V. Petersen·
N.Z. Vet. J. 26: 9-/0
SUMMARY
Downloaded by [University of Wisconsin - Madison] at 09:45 02 February 2015
The effect of bruising on lamb carcasses in tenos of aerobic bacterial load on the affected surface was Investigated. A com parison of swab samples between bruised areas and control areas on the same taracasses showed a significant increase in the bacterial load over the bruised area. This difference might be due to a dilference in the texture of the surfaces of the two areas and further studies in this field, using the tissue-sampling method, are suggested. INTRODUCfION
The effect of wounds and bruises on a lamb carcass varies with the degree of the injury. The extent of tissue damage has a considerable effect on the value ofthe carcass. Underregulation 131 of the Meat Regulations (1969) an inspector must have bruised tissue removed and condemned. The majority of wounds and bruises are classified as minor by in~pectors; these are considered a company responsibility and some may be removed later by meat graders. However, there remains a large number of carcasses with some degree of bruising. Carcasses which have been trimmed to remove bruised tissue will be either downgraded to cutter grade with considerable loss in value or, if trimming is minimal, they will still be eligible for export in carcass form. The inspector's judgment of bruising is based on the appea• Meat Division, Ministry of Agriculture & Fisheries, P.O. Box 3, Longburn. Current address: Meat Division, MAF, P.O. Box 198, Feilding.
rance of the lesions and the extent of the damage. However, wholesomeness of meat is reflected in its shelf-life and it is important that proper judgment is made by Ministry of Agriculture and Fisheries' (MAF) and company staff in desig nating wounds and bruises for removal. In this study, the effect of bruising on the shelf-life of lambs killed at the Longbum Freezing Co. Ltd. was evaluated during the 1975-76 season. Important factors affecting the shelf-life of meat products are the initial bacterial load of the meat and the subsequent growth opportunities for spoilage bacteria(')(4). In the New Zealand meat industry, total aerobic surface counts of up to 1()6/cm 2 for carcasses, or cuts, before freezing are regarded as acceptable; in the past, the majority of samples processed at the Longbum Freezing Co. Ltd. have been well below this level. The bacterial loads of bruised poultry tissue has been inves tigated by several workers. Mc Carthy el al.1lI showed that bruised tissue from broilers had a high aerobic and anaerobic microbial count compared to control samples. Results from their investigations indicated that bruised tissue harboured very few micro-organisms immediately after bruising and that these or ganisms increased in number during the early stages of resolu tion (1·2 days) followed by a rapid decrease to reach the level of· controls within 4·6 days. Hamdy and Barton(l) used a marker strain of Staphylococcus aureus injected instramuscularly into both control and traumatized tissues in chickens; they found that the test or ganisms multiplied rapidly in the bruised areas to reach an average of l.5 x 108 viable cells per gram of tissue after 2 days,
Continued next page
Downloaded by [University of Wisconsin - Madison] at 09:45 02 February 2015
10
whereas the normal tissues appeared to possess a clearing me chanism, highly active against staphylococci, as evidenced by the low average count of670 viable ceUs per gram of tissue. They also showed that the extent of both damage and accumulation of blood and fluid seemed to play an important role in the fate of staphylococci in experimentally-induced infection. The persis tence of S. aureus in bruised poultry tissues was also studied by Roskey and HamdYS,. They suggested that it was primarily due to biochemical alterations in the bruised tissue micro-environ ment, particularly during the early stages of healing. The changes increased growth and respiration ofthe staphylococci at the expense of the production of extracellular proteins such as coagulase, haemolysin, hyaluronidase and enterotoxin. These studies indicate that, at least in poultry, the bacterial load of tissue is affected by bruising but, so far, tbis has not been established in red meat. 1n the past, most of the bacteriological quality control of meat in New. Zealand has been carried out using the swab method described by Nottingham(4' and later simplified by the use of the agar droplet counting technique'6'. The latter method was used in the present study. MATERIALS AND METHODS
The car~asses for this survey were selected from downgraded lambs whIch the company intended to sell in their retail shops. The reason for the downgrading of the individual carcasses was ~ot known, as this information is not supplied on the grading ucket. These "Cutter" lambs are diverted to a separate area on the tooling floor and for 3 days, aU carcasses in this area were examined in the morning. Those with bruising were numbered and set aside for storage in a separate freezer area for 4-6 weeks. Carcasses with similar-sized lesions could be found also in the export grade, but these could not be used because of the cost involved. After storage, the carcasses were railed to a chiller (8° C) where they were left for thawing overnight before being trans ferred to the butcher's shop where swab samples were taken and all lesions were measured. The largest diameter of the lesions was measured with a ruler and the depth of the lesion at the centre of the bruised area was measured with a caliper. All carcasses were swabbed over two areas. Firstly, a sterile cottonwool swab moistened in 0.1 % sterile peptone-water was used with a metal template to delimit an area of5 cm' over the bruised surface of the carcass. Secondly the same area was rubbed with a dry cottonwool swab, and then both swabs were stored in 10 ml peptone-water in universal bottles for carriage to the laboratory. A similar, unaffected area on the opposite side of the carcass was swabbed in the same manner. Samples were stored in a refrigerator at the works' laboratory overnight and the next day the samples were shaken for 2 minutes and I ml of the peptone-water was transferred t09mlof semi-solid agar. This constituted the first dilution and two further decimal dilutions were prepared in a similar manner. From each of these dilutions 5 droplets (each of 0.1 ml) were placed on numbered plates using the Colworth dispenser· and plates were then incubated aerobicaUy at 37° C for 24 hours. The number of colonies on the 5 droplets were counted for each ·dilution using the Colworth dispenser fitted with a projector viewer and counter and the mean of these counts was calculated. The counts per cm' for each sample were calculated and these results analyse.d using a paired t-test. REsULTS The chilling, storage and thawing times for the three groups of carcasses were almost identical (Table I) and it was considered justifiable to pool the data for statistical analysis; also, each ·Colworlh. U.K.
VOL. 26
NEW ZEALAND VETERINARY JOURNAL TABLE I: SUMMARY OF TRIAL CONDITIONS Group Code
No. of Carcasses
A B C
Chilling 10°C I-Sh I-Sh I-Sh
8 10 22
Time Intervals Storage ·12°C 42d 39d 33d
Thawing 8°C app.30h app.30h app.30h
TABLE II: SIZES OF LESIONS INVESTIGATED
Range
Largest diam. (cm) 1.5-12.0
M~
Median
~1
6.25
Depth (mm) 0.5-9.0 D 1.5
TABLE III: TOTAL AEROBIC
New Zealand Veterinary Journal Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tnzv20
Bacteriological evaluation of bruised tissue in lamb carcasses G.V. Petersen a
a b
Meat Division , Ministry of Agriculture & Fisheries , P.O. Box 3, Longburn
b
Meat Division , MAF , P.O. Box 198, Feilding Published online: 23 Feb 2011.
To cite this article: G.V. Petersen (1978) Bacteriological evaluation of bruised tissue in lamb carcasses, New Zealand Veterinary Journal, 26:1-2, 9-10, DOI: 10.1080/00480169.1978.34476 To link to this article: http://dx.doi.org/10.1080/00480169.1978.34476
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
1978
9
NEW ZEALAND VETERINARY JOURNAL
Bacteriological evaluation of bruised tissue In lamb carcasses G. V. Petersen·
N.Z. Vet. J. 26: 9-/0
SUMMARY
Downloaded by [University of Wisconsin - Madison] at 09:45 02 February 2015
The effect of bruising on lamb carcasses in tenos of aerobic bacterial load on the affected surface was Investigated. A com parison of swab samples between bruised areas and control areas on the same taracasses showed a significant increase in the bacterial load over the bruised area. This difference might be due to a dilference in the texture of the surfaces of the two areas and further studies in this field, using the tissue-sampling method, are suggested. INTRODUCfION
The effect of wounds and bruises on a lamb carcass varies with the degree of the injury. The extent of tissue damage has a considerable effect on the value ofthe carcass. Underregulation 131 of the Meat Regulations (1969) an inspector must have bruised tissue removed and condemned. The majority of wounds and bruises are classified as minor by in~pectors; these are considered a company responsibility and some may be removed later by meat graders. However, there remains a large number of carcasses with some degree of bruising. Carcasses which have been trimmed to remove bruised tissue will be either downgraded to cutter grade with considerable loss in value or, if trimming is minimal, they will still be eligible for export in carcass form. The inspector's judgment of bruising is based on the appea• Meat Division, Ministry of Agriculture & Fisheries, P.O. Box 3, Longburn. Current address: Meat Division, MAF, P.O. Box 198, Feilding.
rance of the lesions and the extent of the damage. However, wholesomeness of meat is reflected in its shelf-life and it is important that proper judgment is made by Ministry of Agriculture and Fisheries' (MAF) and company staff in desig nating wounds and bruises for removal. In this study, the effect of bruising on the shelf-life of lambs killed at the Longbum Freezing Co. Ltd. was evaluated during the 1975-76 season. Important factors affecting the shelf-life of meat products are the initial bacterial load of the meat and the subsequent growth opportunities for spoilage bacteria(')(4). In the New Zealand meat industry, total aerobic surface counts of up to 1()6/cm 2 for carcasses, or cuts, before freezing are regarded as acceptable; in the past, the majority of samples processed at the Longbum Freezing Co. Ltd. have been well below this level. The bacterial loads of bruised poultry tissue has been inves tigated by several workers. Mc Carthy el al.1lI showed that bruised tissue from broilers had a high aerobic and anaerobic microbial count compared to control samples. Results from their investigations indicated that bruised tissue harboured very few micro-organisms immediately after bruising and that these or ganisms increased in number during the early stages of resolu tion (1·2 days) followed by a rapid decrease to reach the level of· controls within 4·6 days. Hamdy and Barton(l) used a marker strain of Staphylococcus aureus injected instramuscularly into both control and traumatized tissues in chickens; they found that the test or ganisms multiplied rapidly in the bruised areas to reach an average of l.5 x 108 viable cells per gram of tissue after 2 days,
Continued next page
Downloaded by [University of Wisconsin - Madison] at 09:45 02 February 2015
10
whereas the normal tissues appeared to possess a clearing me chanism, highly active against staphylococci, as evidenced by the low average count of670 viable ceUs per gram of tissue. They also showed that the extent of both damage and accumulation of blood and fluid seemed to play an important role in the fate of staphylococci in experimentally-induced infection. The persis tence of S. aureus in bruised poultry tissues was also studied by Roskey and HamdYS,. They suggested that it was primarily due to biochemical alterations in the bruised tissue micro-environ ment, particularly during the early stages of healing. The changes increased growth and respiration ofthe staphylococci at the expense of the production of extracellular proteins such as coagulase, haemolysin, hyaluronidase and enterotoxin. These studies indicate that, at least in poultry, the bacterial load of tissue is affected by bruising but, so far, tbis has not been established in red meat. 1n the past, most of the bacteriological quality control of meat in New. Zealand has been carried out using the swab method described by Nottingham(4' and later simplified by the use of the agar droplet counting technique'6'. The latter method was used in the present study. MATERIALS AND METHODS
The car~asses for this survey were selected from downgraded lambs whIch the company intended to sell in their retail shops. The reason for the downgrading of the individual carcasses was ~ot known, as this information is not supplied on the grading ucket. These "Cutter" lambs are diverted to a separate area on the tooling floor and for 3 days, aU carcasses in this area were examined in the morning. Those with bruising were numbered and set aside for storage in a separate freezer area for 4-6 weeks. Carcasses with similar-sized lesions could be found also in the export grade, but these could not be used because of the cost involved. After storage, the carcasses were railed to a chiller (8° C) where they were left for thawing overnight before being trans ferred to the butcher's shop where swab samples were taken and all lesions were measured. The largest diameter of the lesions was measured with a ruler and the depth of the lesion at the centre of the bruised area was measured with a caliper. All carcasses were swabbed over two areas. Firstly, a sterile cottonwool swab moistened in 0.1 % sterile peptone-water was used with a metal template to delimit an area of5 cm' over the bruised surface of the carcass. Secondly the same area was rubbed with a dry cottonwool swab, and then both swabs were stored in 10 ml peptone-water in universal bottles for carriage to the laboratory. A similar, unaffected area on the opposite side of the carcass was swabbed in the same manner. Samples were stored in a refrigerator at the works' laboratory overnight and the next day the samples were shaken for 2 minutes and I ml of the peptone-water was transferred t09mlof semi-solid agar. This constituted the first dilution and two further decimal dilutions were prepared in a similar manner. From each of these dilutions 5 droplets (each of 0.1 ml) were placed on numbered plates using the Colworth dispenser· and plates were then incubated aerobicaUy at 37° C for 24 hours. The number of colonies on the 5 droplets were counted for each ·dilution using the Colworth dispenser fitted with a projector viewer and counter and the mean of these counts was calculated. The counts per cm' for each sample were calculated and these results analyse.d using a paired t-test. REsULTS The chilling, storage and thawing times for the three groups of carcasses were almost identical (Table I) and it was considered justifiable to pool the data for statistical analysis; also, each ·Colworlh. U.K.
VOL. 26
NEW ZEALAND VETERINARY JOURNAL TABLE I: SUMMARY OF TRIAL CONDITIONS Group Code
No. of Carcasses
A B C
Chilling 10°C I-Sh I-Sh I-Sh
8 10 22
Time Intervals Storage ·12°C 42d 39d 33d
Thawing 8°C app.30h app.30h app.30h
TABLE II: SIZES OF LESIONS INVESTIGATED
Range
Largest diam. (cm) 1.5-12.0
M~
Median
~1
6.25
Depth (mm) 0.5-9.0 D 1.5
TABLE III: TOTAL AEROBIC
