Microbial growth and communities of packed lamb shoulders

Summary

Previous research on boneless lamb shoulders indicates that consumer acceptability remains high for product that has been vacuum packed for up to 78 days.
However, the growth curves for Total Viable Counts - TVC - and Lactic Acid Bacteria - LAB - have not previously been quantified for vacuum packed lamb shoulders.
The aim of this project was to determine growth curves and collect samples for later ecological - microbial community - analysis.
Anecdotal evidence from the trade suggested that bone-in product often has a shorter shelf-life than the corresponding boneless primal.
While vacuum packing is common practice in Australia, few processors pack product in modified atmosphere, which is used more frequently in New Zealand.
As a result, local data was collected on the shelf-life of these products to demonstrate the potential value of this packaging system to the Australian industry.
Vacuum packed and modified atmosphere - 100% CO2 - packed lamb shoulders, bone-in and bone-out, were stored for up to 12 weeks.
All product types performed very well organoleptically and microbiologically, indicating that at -0.3°C vacuum packed and modified atmosphere packed lamb shoulders can last at least 12 weeks.
No evidence could be found to support anecdotal reports that bone-in product has a shorter shelf-life than the corresponding boneless primal.
However, for bone-in product in a modified atmosphere more holes in the pack were observed.
It was concluded that these may be due to excessive shrinkage, which was observed in all modified atmosphere packs, though this problem is likely to be overcome by changing the gas to meat ratio or gas mixture.