Self contained Food Sample Homogenization Filter Bag for Microbial Analysis

The complexity of food materials owing to the diverse matrices and biochemical composition poses challenge to microbiologists especially to identify the microbial contamination at low level. The present study describes the development and evaluation of a ready to use self-contained food sample homogenization bag (All-In-Bag) with the required sterile diluent and an in-built filter for subsequent clarification of the homogenate for microbiological analysis. Three-ply non-foil laminate comprising outer alumina oxide coated polyester film, middle nylon and inner polypropylene layers were used for the outer layers while non-woven polypropylene sheet with of 50 μ to 100 μ size porosity was sandwiched between the laminated sheets to restrain the food debris but allow the microbial cells to pass through across along with the diluent. The homogenization bag along with the diluent was sterilized by thermal (retort) processing with F0 value (lethality value) of 12 to ensure the sterility of diluent during storage. The effectiveness of the All-in-Bag for the homogenisation of different food sample matrices for microbiological analysis was compared with BagPage®+ bag. All-in-Bag withstood the shearing action during sample paddling in the bag mixer/stomacher and no significant difference was observed for both aerobic plate count. Spike and recovery of E. coli from the different food matrices indicating absence of interference for microbial recovery in newly developed All-in-Bag. The All-in-Bag, the first of its kind with 12 months shelf life does away with the requirement of sterile diluent preparation and additional steps for the clarification of the homogenate and thus making microbial food quality analysis easier in places with limited resources

Spin-Wave Theory of the Spiral Phase of the t-J Model

A graded H.P,realization of the SU(2|1) algebra is proposed.A spin-wave theory with a condition that the sublattice magnetization is zero is discussed.The long-range spiral phase is investigated.The spin-spin correlator is calculated.Comment: 17 page

SYBR Green Real-Time PCR Assay for Detection of the Indicator Bacillus cereus to Validate Thermal Processing of Tender Coconut Water

The purpose of this study is to establish thermal processing validation of tender coconut water by using SYBR green Real time PCR assay for direct detection of the biological indicator bacteria, B. cereus, a frequent cross contaminant in packaged tender coconut water. Nucleotide sequences coding for the hemolytic enterotoxin hemolysin BL (Hbl) widely associated with B. cereus food poisoning was used as the target gene for the real time PCR assay. Specific amplification was observed with B. cereus when the specificity of the assay was examined using other closely related spore forming food spoilage Bacilli. The present real-time PCR assay provides a detection of limit (LOD) of 103 CFU/ml of tender coconut water. The thermal resistance of B. cereus (ATCC 14579) was found that D95 2.46 min and Z value 10.45°C in tender coconut water. To validate the thermal processing conditions, B. cereus was artificially contaminated into coconut water, which was thermally processed and checked with real-time PCR assay to detect the survival of B. cereus in tender coconut water bottles without pre-enrichment. The bacterial load enumerated by the real-time PCR assay correlated with the time consuming standard conventional culture method. The thermal processing of tender coconut water packed in polypropylene bottles was validated with 6D concept and minimum 18 min of process time is required to achieve sterilization value (F-value) of 15. The product was analyzed for its physical, chemical properties and commercial sterility after the validated processing conditions and products were acceptable for 6 months without preservative