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Food & Nutrition
Shelf-life of Australian vacuum packed beef-impact of meat colourJoanne Hughes| CSIRO Coopers PlainsMintrac Meat Inspection & Quality Assurance Conference 21st Oct 2015
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Extension of shelf-life to promote global competitiveness
Falling $AUS, advantageous to export markets
Opportunities for growth in other export markets-Free Trade Agreements (FTAs)Increased demand for high quality Australian beef- especially with the rising Asian middle class
Enhancing our global competitiveness-differentiation in global environment
Background research
30 weeks (-0.5°C ) Micro & sensory
ok
pH can impact on micro &
sensory
Consumer acceptance
lower in darker or paler
muscles
Does meat colour impact shelf-life & eating quality?
“bitter”“sour”“off”
“less flavoursome”“less tender”
Long aged (20 weeks) vacuum packed chilled storage- design3 meat colour scores
1B, 1C (light)2, 3 (medium)4 and above (dark)
324 striploin samples from 3 export plants (mix of pasture & grain fed animals)
Stored at -1°C for 20 weeks at CSIRO
Assessed at 0, 2, 8, 12, 16 and 20 weeks
Determine effect of beef meat colour grade on:Biochemical propertiesMicrobiological growthEating qualityRetail display
Storing for longer reduced appearance & odour scores
Darker colours less acceptable after week 16
Appearance & odour on opening
3
12.00
4
20.00
5
6
2.00
7
8
0
2
8.00
1
16.00
App
eara
nce
scor
e
storage week 12.00 8.00 2.00
8
6
4
2
20.00 0
16.00
7
5
1
3
storage week
Odo
ur s
core
LightMediumDark
Acceptable
Unacceptable
Biochemical properties
Dark meat had a higher pH & less glycogen whereas light & medium colours had a lower pH- similar values observed
0
5.8
5.4
20 5.0
16 12 8
6.0
2
5.6
5.2
storage week
pH
LightMediumDark light medium dark
Glycogen (µmol/g) 37 37 33Lactate (µmol/g) 22 22 20
Dark colours had a higher pH
MLA 2011
Total viable count (TVC)-Increased at week 8 and reached a plateau- After week 8, dark muscles had higher values compared to light & medium coloured muscles
Microbiology- TVC increased at 8 weeks and was higher in dark meat
Dark colours higher TVC
12 8 2 0
8
6
4
2
20 0
16
5
7
3
1
storage week
Tot
al v
iabl
e co
unt (
TVC)
LightMediumDark
TVCs & LABs:- No major differences observed between plants- 2 plants with hot water
decontamination units
Brocothrix:- Similar increase at week 8,
but no difference between meat colours
Microbiology- LAB showed similar to TVCDark colours higher lactic acid bacteria
(LAB)
8 2 0
6
4
2
20 0
16 12
5
7
3
1
storage week
Lac
tic a
cid b
acte
ria (l
og cf
u/sq
cm) Light
MediumDark
MQ4 score (out of 100) was calculated by adding 4 sensory components:• Tenderness 30%• Overall liking 30%• Flavour 30%• Juiciness 10%
• MSA eating quality guide separated into:– 3, 4, 5 star ratings
Eating quality using Meat Standards Australia (MSA)- weeks 2, 12 & 20 only
Improved eating quality with storage > 12 weeksLighter colours continue to improve
MSA MQ4 by colourLight colours continue to improve
3
4
40
12
45
50
2 20
55
60
MQ
4 sc
ore
Storage week
LightMediumDark
Tenderness and juiciness scores increased with storageFlavour started to decrease at 20 weeks, apart from in the light coloured group
Tenderness, juiciness & flavourLight colour continues to improve
1
Lighter colours continued to improve
in eating quality
35
40
45
12
50
55
60
65
2 20 Storage week
Ten
dern
ess
LightMediumDark
35
40
12
45
50
55
20 2
60
Juici
ness
Storage week
LightMediumDark
40
12
45
50
2 20
55
60
Fla
vour
Storage week
LightMediumDark
Colour groups had a similar retail display life
Retail display steaksWeek 20, after 3 days retail display
Light
Medium
Dark
Steaks visually suitable 2 weeks = 6 days
12 weeks = 4 days20 weeks = 3 days
In summaryStoring meat reduced the appearance and odour of the product, but all meat
colours were still acceptable at week 20.
The development of spoilage associated microflora was more pronounced in dark muscles & consequently these muscles have a higher likelihood of reduced storage life.
All meat colours improved in eating quality with aging, especially between 2 and 12 weeks.
After 20 weeks storage, MQ4 scores indicate a 3 star product is achieved, meaning light & medium meat colours can achieve a “good everyday” eating quality when stored appropriately.
Future studies/ going forward
Determine shelf life/eating quality of long aged beef for export markets- “real life situation”
- especially to emerging markets- Biochemical, microbiological & sensory/ eating quality
Current project looking at the effect of purge on shelf-life of vacuum packed chilled meat, especially for Egyptian clients.ABARES Beef & veal Pork Lamb Chicken
Export vol 2013-14kt%
1,184/1611
74%
47/360
13%
250/ 470
53%
38/1066
4%
Main export markets
USA, Japan & China
USA, Canada& China
Middle east,USA & China
AcknowledgementsFunding from:
• Meat Livestock Australia
• Australian Meat Processors Corporation
Sensory:
• Rod Polkinghorne & Alan Gee
• CSIRO team & statistican (Gavin Kearney )
• Beef Processors
