Identifying storage thresholds in frozen and chilled lamb meat

Cassius Coombs

Research output: ThesisMasters Thesis

391 Downloads (Pure)

Abstract

The experiment on which this thesis is based tested the effects of chilled,
frozen and chilled-then-frozen storage of lamb at various durations. It was
hypothesised that prolonged chilled storage (up to 8 weeks) would lead to
rancidity, compromised sensory and nutritional qualities and spoilage due to
proliferation of specific microbes. Likewise, it was hypothesised that following chilled storage, frozen storage as per industry practice would preserve quality regardless of duration. Following prescribed chilled-thenfrozen durations however, it was hypothesised that meat frozen for longer durations (up to 52 weeks) would exhibit a faster loss of quality upon retail display post-thawing.

A total of 360 lamb m. longissimus lumborum (LL) were collected from a
collaborating export abattoir and allocated to storage durations of 0, 2, 4, 6
and 8 weeks chilled storage and 0, 4, 8, 12, 24 and 52 weeks frozen storage
(n = 360). Frozen samples were held at two different frozen storage
temperatures (-12 and -18 °C). Upon completion of each chilled-then-frozen
storage duration treatment, samples were sub-sampled for instrumental
analyses of meat quality and safety traits and one sub-section was placed
under simulated retail display conditions for 3 days (approximately 72
hours) where instrumental colour measures were taken daily.

Results from this experiment indicated that chilled-then-frozen storage
influenced sensory quality by decreasing shear force and colour stability and
altering lipid oxidation. Nutritional quality, based upon proportions of
health-claimable fatty acids, and food safety, were maintained following
maximum chilled and frozen storage periods in this experiment, although
spoilage microbes (lactic acid bacteria and Brochothrix thermosphacta)
were close to proliferating above spoilage thresholds following 8 weeks
chilled-only storage. Following this experiment, storage thresholds (chilled,
frozen and chilled-then-frozen) could be formed based upon previously
determined consumer thresholds for selected meat quality and safety traits
Original languageEnglish
QualificationMaster of Philosophy
Awarding Institution
  • Charles Sturt University
Supervisors/Advisors
  • Friend, Michael, Principal Supervisor
  • Hopkins, David, Principal Supervisor
  • Holman, Benjamin, Advisor
Thesis sponsors
Award date23 Mar 2017
Place of PublicationAustralia
Publisher
Publication statusPublished - 2017

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