Exposure Time on Bacteria Flora/Count and Shelflife of Canned Sardine (Sardinella pilchardus) Under Ambient and Cold Storage Conditions

摘要

This study is aimed at investigating the exposure time on bacteria flora/count and shelflife of conned sardine (Sardinella pilchardus) under ambient and cold storage conditions. Twenty five cans with an average weight of 165.05 g of the Titus (with an expiry date of 4 years(30/9/2004-30/9/2008 pf batch no 1432) were purchased and stored under the ambient at an average temperature of 27° and cold (-4°) storage conditions as samples for 12 weeks. Proximate analysis of the samples were taken at the beginning of the experiment and at the end for both the ambient stored and cold stored (after an exposure time of 24 h). Initial base line and biweekly studies were carried out for 12 weeks for (a) Ogranoleptic (odour, taste, texture, appearance, rigidity of fillet, colour and reaction of fish with can (b) Chemical (Trimethylamine (TMA), Peroxide Values (PV) and Thiobarbituric Acid (TBA) and lastly 8 Microbiological analysis for bacteria count and identification of the bacteria on the samples from each storage environment after an exposure time of 24 h in each cases. All the chemical parameters (TMA, TBA and PV) were significantly (p<0.05) correlated with exposure/storage time. Correlation coefficients r = 0.60, r = 0.66 and r = 0.54 were recorded respectively with all indicating spoilage rate increases progressively with exposure time/storage period. Highest PV ranges of (0.023-0.715), TBA (0.057-1.056) and TMA (1.01 x103-3.63 x 103) were recorded for canned sardines stored at ambient temperatures of 27°. However these are still within acceptable tolerance limit. Organoleptic assessment with average scores of 5.5 and 6.0 recorded for cold and ambient stored samples. No viable bacteria count was recorded for cold stored samples throughout the experiment. However the range initial 0.1 x 104 and final 5.0 x 104 cfug B1 total viable count recorded for ambient storage were still below the minimum bacteria count for spoilage, that could cause significant or deleterious effect that could result in food poisoning. Traces of the following bacteria sp. were recorded at ambient temperatures (a) Bacillus subtilis (1.2 x 104cfng-1) (b) Streptococcusfaecium (0.9 x 104 cfng-1), 8 Proteus vulgaricus (0.7 x 104 cfng-1) (d) Pediococcus halophilus (0.6 x 104 cfng-1) (e) Micrococcus acidiphilus (0.4 x 104 cfug-1) (f) Streptococcus lactis (0.4 x 104 cfng-1) and (g) Aerobacter aerogenes (0.4 x 104 cfng-1) w hile fungi sp. Aspergillus terrens (0.1 x 104 cfng-1) Aspergillus niger (0.3 x 104 cfng-1) were recorded also for samples stored at ambient temperature of 27°. Hence in view of this the four years recommended expiry data may be upheld for canned sardine (Sardinella pilchardus fish products in oil sources provided the HACCP (Hazard Analysis and Critical control points) and closely monitored. It is therefore recommended that exposure of c anned sardine in oil should not exceed 12-24 h under whatever food storage temperatures to avoid food poisoning.