BIOPRESERVATION OF MILK USING BACTERIOCINSPRODUCING LACTIC ACID BACTERIA ISOLATED FROM KUNUN ZAKI IN ZARIA, KADUNA STATE, NIGERIA
BIOPRESERVATION OF MILK USING BACTERIOCINSPRODUCING LACTIC ACID BACTERIA ISOLATED FROM KUNUN ZAKI IN ZARIA, KADUNA STATE, NIGERIA
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Date
2016-09
Authors
ADAMU, AMINA GOGO
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Abstract
Bacteriocins from Lactic acid bacteria are used in preservation of foods due to their beenGenerally Regarded as Safe (GRAS) status.Consumers awareness over chemical free foods has led to the search for alternative method of food preservation using Lactic acid bacteria. Lactic acid bacteria were isolated from kunun zaki in Zaria metropolis, Kaduna State, Nigeria. Sampling technique used was a non probability type, convenience method. The pH of Kunun Zaki sample ranged 5.68 ± 0.09 - 5.80±0.09, mean count of Lactic acid bacteria ranged 1.14 x 106 ± 2.4 x 104 - 1.8 x 106 ± 2.3 x 104,Analytical Profile Index (API 50 CH KIT) was used to identify the organisms to Species level as Lactococcus lactis, Lactobacillus plantarum, Lactobacillus acidophilus, Pediococcus pentosaceous, Lactobacillus fermentum and Lactobacillus paracasei. Lactococcus lactis, Lactobacillus plantarum, Lactobacillus acidophilus and Pediococcus pentosaceous had the potential for bacteriocin activity following screening by agar well diffusion assay, zones of inhibition were measured as Staphylococcus aureus (3.10 ± 0.03 -8.10 ± 0.07mm), Escherichia coli (1.20 ± 0.34mm), Pseudomonas aeruginosa (0.64±0.07 -2.11±0.42mm), Listeria monocytogenes(3.10 ± 0.03-9.25 ± 0.40mm),Salmonella Typhimurium(1.28 ±0.92-1.36±0.62mm) and Clostridium botulinum (2.34 ± 0.08-7.43 ± 0.53mm). Production study reveal that pH 5 and temperature 370C were optimum for bacteriocin activity. Assessment of the Biopreservative potential of bacteriocin on milk showed that the shelf life of milk was extended at 40C for 6 days on addition of Nisin and 5 days when Plantaricin, Acidophilin and Pediocin were inoculated. At 80C, the shelf life of milk was extended for 4 days after inoculation of Nisin, Plantaricin, Acidophilin and Pediocin while the initial shelf life of milk without bacteriocin (control) was 4 days, at ambient temperature, shelf life of milk was extended for 2 days (after inoculation of Nisin, Plantaricin, Acidophilin and Pediocin) while the initial shelf life of milk without bacteriocin (control) was 1 day. pH of milk ranged from 5.4±0.1-4.0±0.1 while total titratable acidity ranged from 0.0217±0.001 -0.120±0.003. Findings from the work showed that the milk sample inoculated with bacteriocin was acceptable. Proximate composition of milk sample such as Moisture content (64.00±1.62 - 66.67±2.67) of bacteriocin inoculated milk showed a significant difference (P ≤0.05) compared with milk without bacteriocin (control), Ash content (4.30±0.2 - 4.60±0.6), Fat content (3.10±0.1 - 3.37±0.1), Protein content (20.00 ±0.06-21.07±0.54) and carbohydrate content (3.10±0.61 - 6.77±0.43) by difference also showed that bacteriocins from Lactic acid bacteria isolated from kunun Zaki could serve as a food additives for biopreservation. The use of bacteriocins from Lactic acid bacteria as a natural preservative in milk has shown to be effective against foodborne pathogens and may be used as an alternative to the commonly used preservatives in response to consumers demand for natural products.
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A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF A MASTER OF SCIENCE DEGREE IN MICROBIOLOGY DEPARTMENT OF MICROBIOLOGY FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIA
Keywords
BIOPRESERVATION,, MILK USING BACTERIOCINSPRODUCING,, LACTIC ACID,, BACTERIA ISOLATED,, KUNUN ZAKI,, ZARIA, KADUNA STATE, NIGERIA