Investigating the Safety of Meat Co-Products: Microbiology Aspect
Investigating the safety of meat co-products: microbiology aspect A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at University of Otago By Linakshi Weerakoon 2020 Abstract Meat co-products (offal) are rich in protein and essential nutrients and have been consumed as delicacies worldwide. China, New Zealand’s largest red meat export market is a country where offal dishes are frequently consumed. As foodborne diseases are a major challenge faced by Chinese consumers, it is important to ensure the quality and safety of offal consumed in China. The objectives of the study were; firstly to investigate the presence of E. coli/ coliforms, Campylobacter jejuni, Salmonella, Clostridium perfringens, Listeria monocytogenes and determine the aerobic plate count (APC) of sheep offal (testes, skirt, liver, tripe, kidney, heart, tail and pizzle) purchased from New Zealand and China using conventional microbiology enumeration methods. Secondly, the distribution of microbial populations present in the sheep offal were investigated using metagenomics. Thirdly, the presence of mycotoxins, aflatoxin B1 (AFB1), deoxynivalenol (DON), zearalenone (ZEA), T-2 toxin and ochratoxin A (OTA) in sheep offal were investigated. Lastly, the decontamination efficiency of chitosan on meat co- products was investigated. Campylobacter jejuni, Salmonella, Clostridium perfringens, Listeria monocytogenes were not present in any of the sheep offal. APC counts obtained for testes, skirt, liver, tripe , kidney, heart, tail and pizzle were 1.85 ± 0.58, 1.65 ± 0.53,1.41 ± 0.28, 1.61± 0.51,1.53 ±0.97, 2.16 ± 0.18 and 2.35 ± 0.46 log CFU/g, respectively for the New Zealand sheep offal and 6.27 ± 0.25, 6.04± 1.53, 6.36 ± 0.72, 5.70 ± 0.92, 7.56 ± 0.58, 7.41 ± 0.56, 7.41 ± 0.45 and 7.44± 1.11 log CFU/g, respectively for the Chinese sheep offal.
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