Studies on the selection of a suitable packaging material for pre- and post-irradiation storage of cereal grains in Ghana

Twenty different species of fungi belonging to the genera Aspergillus, Cephalosporium, Dreschlera, Fusarium, Mucor, Neurospora, Rhizoctonia, Rhizopus, Penicillium and Trichoderma were isolated from jute and woven polypropylene sacks using the blotter test, solid medium test and the decimal serial dilution technique. There was a highly significant difference (Students' t-test, P < 0.05) between the larger number of fungal colonies associated with jute sacks than with woven polypropylene sacks. Correspondingly, more fungal species (16) were isolated from jute sacks than from woven polypropylene sacks (9). The blotter test showed that in the absence of an exogenous supply of nutrients, 88% of the sections of jute sacks supported in vivo growth of fungal spores whilst woven polypropylene sacks could not support the growth of contaminating spores. Evidence is presented that mould and yeast counts on sections of new-woven polypropylene sacks incubated at 80 and 90% relative humidity (R.H.) for four months increased by less than 1 log cycle, whilst in similar sections hung on a line under ambient conditions (75 ± 10% R.H. and 28 ± 3°C) viable counts of spores decreased. Sections of fresh jute sacks similarly treated supported 1 log cycle increase in mould and yeast counts at 80% R.H. and 2 log cycles increase at 90% R.H. after four months of storage. Gamma-ray irradiation (4.0 kGy) reduced the mould and yeast counts on new jute and new woven polypropylene sacks by 1 and 2 log cycles, respectively, but post-irradiation storage at 80% R.H. allowed moulds like Aspergillus flavus, A. niger, Fusarium nivale and Penicillium verrucosum var. cyclopium to commence growth on jute sacks. This presumably, may act as a springboard for infecting grain contents of jute sacks. Inert woven polypropylene sacks failed to support fungal growth.     

Influence of packaging material on moisture sorption and the multiplication of some toxigenic and non-toxigenic Aspergillus spp. infecting stored cereal grains,cowpea and groundnut

The moisture sorption isotherms of jute sack were determined at 12, 22, and 32°C by a standard procedure using glycerol:water mixtures providing equilibrium relative humidities (ERH) of 65, 70, 75, 80, 90 and 95%. The equilibration period of jute sack kept at 65–85% was found to be between 6–8 days whereas the moisture content (MC) and weight of jute sack kept at 90–95% continued rising. The amount of moisture absorbed at 12°C was significantly greater (P < 0.05) than at 32°C. Analysis of variance applied to collected data of adsorption at ERH 85% (a_w 0.85) and desorption ERH 20% (a_w 0.20) showed that incubation period, type of commodity and type of packaging material as well as the interaction of these factors significantly influenced the moisture sorption and desorption by cowpea, groundnut (shelled), white maize, millet and sorghum. Each food commodity absorbed water differently in the jute and woven polypropylene sacks. However, food commodities stored in jute sack significantly absorbed and desorbed moisture to a greater extent than the same produce stored in woven polypropylene. Mould and yeast count on seed and grain lots in woven polypropylene at ERH 20% were 1.0–1.5 log cycles lower after 6 months storage than same seed and grain lots kept in jute sack. Correspondingly, mould and yeast count on seeds stored in woven polypropylene at ERH 85% were 2–3 log cycles lower than same produce kept in jute sack. Both ambient sttorage humidity and type of storage sack had profound effect on the occurrence of toxigenic and non-toxigenic mould species on cowpea, groundnut, maize, millet and sorghum. The toxigenic moulds and non-toxigenic Aspergillus species reduced considerably the self-life of seeds kept particularly in jute sacks. Practical implications of these findings are discussed in relation to grain food storage in the tropics.     

Triple bagging hermetic technology for post-harvest preservation of paddy rice Oryza sativa L. in the Sahel of West Africa

Trials of the Purdue Improved Crop Storage (PICS) bag technology for the storage of paddy rice, Oryza sativa L., were conducted in Burkina Faso, Ghana and Niger. Paddy rice naturally infested with insects, the most abundant species being Tribolium spp. and Rhizopertha dominica, was sealed in triple layer PICS bags, or in conventional woven polypropylene sacks. At the end of 7–18 months of storage in PICS bags the number of insects did not increase, the weight of 100 seeds did not change, and the proportion of damaged seeds was not different from that present when the paddy was first put into the bags. By contrast, paddy stored in the conventional way in woven polypropylene bags exhibited weight losses ranging from 3 to 8.7%. In Bolgatanga, Ghana, where paddy was stored for 18 months, germination of paddy kept in the PICS bags was comparable to that present at the beginning of the experiment. PICS bags can be used for the safe, low-cost, insecticide free storage of paddy rice.     

The persistence and activity of permethrin and chlorpyrifos-methyl sprays on jute and woven polypropylene bags

To simulate the treatment of commercial bags, the persistence and biological activity on jute and woven polypropylene sheets of permethrin emulsifiable concentrate, were studied. The residues produced in wheat grains under the sprayed sheets were also determined. Residues were analysed by gas-liquid chromatography, and bioassays with Tribolium confusum Duv. on the treated materials.The insecticide residues were of shorter persistence on jute than on polypropylene sacking material. However, higher residues were found in the grain under jute than under polypropylene bags. Permethrin was found more effective for beetle control and resulted in less residue in the grain than chlorpyrifosmethyl. Polypropylene covering provided more protection to the wheat against insect and insecticide penetration as compared with jute covering.     

Incidence of Penicillium roqueforti and roquefortine C in silages

Wilted grass and whole-crop maize silages taken from farm silos in northern Germany were analysed for fermentation pattern, mould counts and composition of mycoflora as well as for roquefortine C. In general, increasing DM contents of visibly unmoulded silages resulted in decreasing amounts of volatile fatty acids and a greater portion of samples with a high number of mould propagules. The average mould count of these silages was found to be 1·4×10⁴ cfu g⁻¹, whereas visibly moulded samples contained about 1×10⁸ cfu g⁻¹. Penicillium roqueforti was the predominating fungal species in silages occasionally accompanied by species of the genera Aspergillus, Mucor, Monascus and/or Geotrichum. Penicillium roqueforti was detected in 89% of the visibly moulded and in 85% of the visibly unmoulded samples. Of 24 visibly moulded silages tested, 21 samples contained roquefortine C, a mycotoxin known to be produced by P roqueforti. The highest level of roquefortine C found was 36 mg kg⁻¹ DM. Even 6 of 24 visibly unmoulded samples analysed for this mycotoxin were contaminated with roquefortine C but only in trace amounts. Roquefortine C is considered as a model compound for the biosynthesis of toxic fungal metabolites produced by P roqueforti in silages. The P roqueforti-count can be employed as a criterion to predict the contamination of silages with mycotoxins produced by this fungal species. © 1998 SCI.     

Mycoflora and aflatoxin contamination in shelled pistachio nuts

A total of 143 pistachio nut samples collected during harvest, storage and processing were examined for mould growth and aflatoxin production. The mould count was in the range of 10³?10⁴ cfu g^?1 and 10⁵?10⁶ cfu g^?1 for the harvest and storage samples, respectively. The growth of Aspergillus flavus was 38-5-39-5% on the surface of the shells and 6–16% on the kernels without aflatoxin production. The contamination level of A flavus varied among samples collected from different regions. Peeling off the soft shell of pistachio nuts by hand reduced the contamination risk of A flavus to kernels. The predominant flora on stored pistachio nuts were Aspergillus, Penicillium, Cladosporium, Rhizopus, while the genera of Ulocladium, Trichothecium, Aureobasidium and Eurotium were less frequent. Thirty-five percent of the A flavus isolates produced aflatoxins on synthetic media.     

The effect of different cooking procedures on microbiological and chemical quality characteristics of Tekirdaǧ meatballs

In this research, the effects of different cooking processes (grilling, oven, and microwave cooking) on microbial flora and chemical composition of the raw and cooked meatballs as consumed in Tekirdaǧ were investigated. Microbial flora of the raw meatballs was as follows: total bacteria, 6.02×10⁶ cfu/g; psychrophilic bacteria, 1.3×10⁵ cfu/g; yeast and mould, 2.4×10⁵ cfu/g; coliforms, 1.1×10⁵ cfu/g; Escherichia coli, 1.0×10² cfu/g; total staphylococcae, 3.3×10² cfu/g; Staphylococcus aureus, 85 cfu/g. While Salmonella was found in only one sample, none of the samples contained Clostridium perfringens. The cooking processes clearly decreased the microbial flora (2–3 log cycles in grilling (71°C) and oven‐cooked (79°C( 3–4 log cycles in microwave (97°C) heating) of the meatballs. However, because of the crust formation and high moisture losses from the meatball surface in microwave heating, some sensorial defects were observed in the final product. Also, fat and moisture losses were higher in microwave cooking compared to the other cooking processes. In conclusion, it is advised to use slightly higher temperatures than used in the grilling or conventinal cooking procedures to increase microbial quality of the meatballs studied in this research.     

EXPOSURE TIME ON BACTERIA FLORA/COUNT AND SHELF LIFE OF CANNED SARDINE (SARDINELLA PILCHARDUS) UNDER AMBIENT AND COLD STORAGE CONDITIONS

This study is aimed at investigating the exposure time on bacteria flora/count and shelf life 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 expiration date of 4 years (September 30, 2004 to September 30, 2008 of batch no. 1432) were purchased and stored at the ambient temperature of 27C and cold (?4C) storage conditions as samples for 12 weeks (precisely between June 15 and September 10, 2005 when the experiment lasted). Proximate analysis of the samples was taken at the beginning of the experiment and at the end for both the ambient and cold stored (after an exposure time of 24 h). Initial baseline and biweekly studies were carried out for 12 weeks for: (1) organoleptic (odor, taste, texture, appearance, rigidity of flesh, color and reaction of fish with can); (2) chemical (trimethylamine [TMA], peroxide values [PVs] and thiobarbituric acid [TBA]); and lastly (3) 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 case. All the chemical parameters (TMA, TBA and PV) were significantly (P < 0.05) correlated with exposure/storage time. Correlation coefficients r = 0.60, 0.66 and 0.54 were low in all classes therefore indicating spoilage rate increases slightly with exposure time/storage period. The highest PV (0.023–0.715), TBA (0.057–1.056) and TMA (1.01 × 10³–3.63 × 10³) ranges were recorded for canned sardines stored at ambient temperature of 27C. However, these are still within acceptable tolerance limit (i.e., organoleptic score of 4–7). Organoleptic assessment with average scores of 5.5 and 6.0 was recorded for cold and ambient stored samples. No viable bacteria count was recorded for cold‐stored samples throughout the experiment. However, the range initial 1.0 × 10⁵ and final 5.0 × 10⁴ cfu/g total plate counts 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 bacterial species were recorded at ambient temperatures: (1) Bacillus subtilis (1.2 × 10⁴ cfu/g); (2) Streptococcus faecium (9.0 × 10³ cfu/g); (3) Proteus vulgaricus (7.0 × 10⁵ cfu/g); (4) Pediococcus halophilus (6.0 × 10⁵ cfu/g); (5) Micrococcus acidophilus (4.0 × 10³ cfu/g); (6) Streptococcus lactis (4.0 × 10³ cfu/g); and (7) Aerobacter aerogenes (4.0 × 10³ cfu/g), while fungal species Aspergillus terreus (1.0 × 10³ cfu/g) and Aspergillus niger (3.0 × 10³ cfu/g) were recorded also for samples stored at ambient temperature of 27C. Hence, in view of this, the 4‐year recommended expiration date may be upheld for canned sardine (S. pilchardus fish products in oil sources) provided the hazard analysis and critical control points, and closely monitored. It is, therefore, recommended that exposure of canned sardine in oil should not exceed 12–24 h under whatever food storage temperatures to avoid food poisoning.     

Probiotic Bifidobacterium animalis ssp. lactis Probio-M8 improves the properties and organic acid metabolism of fermented goat milk

The addition of Bifidobacterium to goat milk has dual effects on health, for which various inherent nutrients of goat milk are retained and live probiotics are provided. We explored the effect of Bifidobacterium animalis ssp. lactis Probio-M8 (Probio-M8) on fermentation characteristics, formation of organic acid, sensory properties, and storage characteristics of fermented goat milk (with added 4.0% sucrose). Addition of Probio-M8 decreased the fermentation time and significantly increased the content of functional organic acids, such as acetic acid, and functional long-chain unsaturated fatty acids, including linoleic acid, α-linolenic acid, and docosahexaenoic acid. Furthermore, the contents of medium-chain and short-chain fatty acids, which are related to “goaty” flavor, were significantly lower in the Probio-M8 treatment compared with the control. The number of living Probio-M8 decreased from 8.27 log cfu/mL (1.80 × 10⁸ cfu/mL) to 7.94 log cfu/mL (0.79 × 10⁸ cfu/mL) after 28 d of storage. Titratable acidity and pH value did not differ between the control group and experimental group (containing Probio-M8). Sensory evaluation indicated a lower goaty flavor and odor in the Probio-M8 fermented milk. Our results suggest that the addition of the probiotic Probio-M8 could improve the sensory, physicochemical, and functional properties of fermented goat milk.     

The Hybrid Effect of Jute/Kenaf/E-Glass Woven Fabric Epoxy Composites for Medium Load Applications: Impact,Inter-Laminar Strength,and Failure Surface Characterization

This research has been carried out to find better hybrid natural/glass fiber-reinforced composites for engineering applications. This research work studied the impact and inter-laminar strength of E-glass with jute/kenaf woven fabric epoxy composites with the aim of evaluating the hybridization effects on different laminate stacking sequences made with jute, kenaf, and E-glass fabrics by the vacuum bagging method. All the laminates were prepared in 300 × 300 mm² with a total of five plies maintained at 3 mm thickness, by varying the number and position of jute, kenaf, glass layers so as to obtain nine different stacking sequences. Among them, one group of all pure jute, pure kenaf, and pure E-glass laminates were also fabricated for comparison purpose. The specimen preparation and testing were carried out as per ASTM standards. From the results, it is shown that the properties of jute/kenaf fabrics-reinforced epoxy composites can be enhanced by hybridization with the addition of glass fabrics. The hybridization of jute/kenaf fabrics with E-glass fabrics provides a method to improve the mechanical impact and inter-laminar strength over pure natural fiber-reinforced composites. The hybrid laminate having E-glass and kenaf fiber plies as skin layers and jute fiber plies as core layers showed better properties compared to other laminates.     

PRESERVATION OF FISH SPREAD WITH ENTEROCINS 1071A AND 1071B, TWO ANTIMICROBIAL PEPTIDES PRODUCED BY ENTEROCOCCUS FAECALIS BFE 1071

Enterocins 1071A and 1071B, produced by Enterococcus faecalis BFE 1071, kept the total aerobic cell numbers in fish spread between 8 × 10⁴ and 2 × 10⁵ cfu/g for the first 6 days of storage. The total aerobic cell numbers in a batch preserved with a combination of sodium benzoate (0.045%, w/w) and potassium sorbate (0.059%, w/w) remained between 8 × 10⁴ and 2 × 10⁵ cfu/g during the first 18 days of storage. In a batch containing no preservatives, cell numbers gradually increased from 1 × 10⁵ to 1 × 10⁸ cfu/g over 21 days. The spoilage organisms were identified as Staphylococcus epidermidis and atypical Proteus vulgaris. The pH of all batches remained constant over the 21‐day storage period, with minimal variations recorded in textural and organoleptic qualities. The number of microbial cells recorded in fish spread preserved with enterocins 1071A and 1071B was 8 × 10⁶ after 21 days of cold storage (4C), whereas microbial cell numbers of 1 × 10⁸ were recorded in fish spread that had not been preserved.     

Fungi isolated from packaging materials: Their role in the production of 2, 4, 6-trichloroanisole

Fungi isolated from fibreboard cartons, paper sacks and jute sacks were assessed for their ability to methylate 2, 4, 6-trichlorophenol in a defined, reduced-water-activity growth medium. When extracts of individual cultures were analysed by gas chromatography-multiple ion monitoring mass spectrometry, 17 of the 31 species, initially selected by sensory techniques, were found to produce 2, 4, 6-trichloroanisole. Quantitative analyses showed that the most efficient methylators in the defined liquid medium were Paecilomyces variotii, Fusarium oxysporum, Penicillium crustosum, Pen citrinum, Pen brevicompactum and one strain of Aspergillus flavus. The role of these fungi in the production of 2, 4, 6-trichloroanisole in packaging materials contaminated with 2, 4, 6-trichlorophenol is discussed.     

Investigation of physicochemical composition and microbial communities in traditionally fermented vrum from Inner Mongolia

Mongolian traditionally fermented vrum is known for its functional characteristics, and indigenous microbial flora plays a critical role in its natural fermentation. However, studies of traditionally fermented vrum are still rare. In this study, we investigated the artisanal production of traditionally fermented vrum from Inner Mongolia. In general, its physicochemical composition was characterized by 34.5 ± 8% moisture, 44.9 ± 12.1% fat, 10.6 ± 3.2% protein, and 210 ± 102°T. The total lactic acid bacteria and yeast counts ranged from 50 to 2.8 × 10⁸ cfu/g and from 0 to 1.1 × 10⁶ cfu/g, respectively. We studied bacterial and fungal community structures in 9 fermented vrum; we identified 5 bacterial phyla represented by 11 genera (an average relative abundance >1%) and 8 species (>1%), and 3 fungal phyla represented by 8 genera (>1%) and 8 species (>1%). Relative abundance values showed that Lactococcus and Lactobacillus were the most common bacterial genera, and Dipodascus was the predominant fungal genus. This scientific investigation of the nutritional components, microbial counts, and community profiles in Mongolian traditionally fermented vrum could help to develop future functional biomaterials and probiotics.     

Studies on Mechanical and Morphological Characterization of Developed Jute/Hemp/Flax Reinforced Hybrid Composites for Structural Applications

In the present study, an attempt has been made to develop and characterize natural fiber-based composites (jute/epoxy, hemp/epoxy, flax/epoxy) and their hybrid composites (jute/hemp/epoxy, hemp/flax/epoxy, and jute/hemp/flax/epoxy) using hand-lay-up technique. Mechanical characterization (tensile, flexural, impact, and hardness test) of the developed composites was performed. The interface between fiber and matrix was examined using scan electron microscopy (SEM). Among (jute/epoxy, hemp/epoxy, flax/epoxy), flax/epoxy composite has shown higher hardness (98 Shore-D) and tensile strength (46.2 MPa) whereas better flexural and impact strength have been shown by hemp/epoxy (85.59 MPa) and jute/epoxy (7.68 kJ/m²) composites respectively. Results showed that hybrid composites observed better mechanical properties. Jute/hemp/flax/epoxy hybrid composite showed the highest tensile strength, modulus and impact strength of 58.59 MPa, 1.88 GPa, and 10.19, kJ/m², respectively. Jute/hemp/epoxy hybrid composite achieved the maximum flexural strength of 86.6 MPa.     

EFFECT OF PROCESSING ON BACTERIAL POPULATION OF CUTTLE FISH AND CRAB AND DETERMINATION OF BACTERIAL SPOILAGE AND RANCIDITY DEVELOPING ON FROZEN STORAGE

Processing techniques like cooking and freezing exhibited significant (P < 0.001) reduction in the bacterial load of cuttlefish, Sepia pharaonis, and marine crab, Portunus pelagicus. Raw cuttle fish had 2.4 × 10⁷ cfu/g which on cooking reduced to 9.7 × 10⁶ cfu/g. Freezing reduced the bacterial load further as cooked frozen product had only 9.9 × 10⁴ cfu/g. Similarly, raw crab had 2.6 × 10⁷ cfu/g which on cooking reduced to 6.5 × 10⁶ cfu/g. A further reduction in bacterial load was seen after freezing as cooked frozen crab exhibited only 7.3 × 10⁴ cfu/g. Escherichia coli and Staphylococcus aureus were present in the limit of acceptability for fish and fish products. Salmonella typhimurium and Vibrio cholerae were absent even in raw stage. Biochemical analysis performed on stored frozen products of cuttle fish and crab exhibited a significant (P ≤ 0.05) increase in bacterial spoilage and rancidity with increasing days of storage. Total volatile base nitrogen, trimethylamine, thiobarbituric acid and free fatty acid contents in frozen products of cuttle fish and crab increased significantly with 120 days of frozen storage.     

Chemical,Microbial and Sensory Properties of Candied-Pineapple and Cherry Cakes

The chemical, sensory and microbial qualities of candied-pineapple and cherry cakes were investigated. Both cake samples were also analyzed for chemical composition and microbial load before, during and after 56 days storage at room temperature. There were significant differences (p < 0.05) in the physico-chemical composition of the cherry cake and candied pineapple cake except for protein values of 9.00% and 8.63% respectively and magnesium content with values of 0.23% and 0.27% respectively. Sensory evaluation results showed significant differences (p < 0.05) between the two samples with the exception of colour (7.84) for both samples and texture (7.84 and 7.80) for cherry and candied pineapple cakes, respectively. In terms of general acceptability, the candied-pineapple cake was most preferred (8.52). The microbial loads (bacterial and fungal) of the candied pineapple cake were lower than the cherry cake throughout the duration of the 56 days storage at room temperature. The highest bacterial load was recorded after the 28th day (148.0 × 10⁵ cfu/g) and (194.30 × 10⁵ cfu/g) for candied pineapple and cherry cakes respectively. The fungal load was also highest at 28th day of storage (14.33 × 10¹ cfu/g) and (12.67 × 10³ cfu/g) for candied pineapple and cherry cakes respectively. The total viable counts (TVC) were within acceptable limits for human consumption. Therefore, candied-pineapple can readily substitute cherry in fruit cake making in Nigeria.     

Fermentation and aerobic stability of rehydrated corn grain silage treated with different doses of Lactobacillus buchneri or a combination of Lactobacillus plantarum and Pediococcus acidilactici

We investigated the effects of different types and doses of inoculants for ensiling rehydrated corn grain. Shelled corn was finely ground and rehydrated to 35% moisture. Treatments were as follows: (1) control (no additives); (2) Lactobacillus plantarum and Pediococcus acidilactici (LPPA) at a theoretical application rate of 1 × 10⁵ cfu/g; (3) LPPA at 5 × 10⁵ cfu/g; (4) LPPA at 1 × 10⁶ cfu/g; (5) Lactobacillus buchneri (LB) at 1 × 10⁵ cfu/g; (6) LB at 5 × 10⁵ cfu/g; and (7) LB at 1 × 10⁶ cfu/g. We detected no effect of inoculant dose. Gas losses were greater in silages treated with LB compared with control and LPPA silages. Treating silages with LB reduced the concentrations of lactic acid and ethanol and increased silage pH and concentrations of acetic acid, propionic acid, and 1,2-propanediol. At silo opening, silages treated with LB had higher counts of lactic acid bacteria but lower yeast counts than the control silage. Aerobic stability was greater for silages treated with LB and lower for silages treated with LPPA compared with the control. The LB reduced dry matter (DM) losses during aerobic exposure, whereas LPPA increased them. Prolamin content was lower in silages treated with LB compared with the control, resulting in greater ruminal in situ DM degradability. Inoculating LB to a dose of 1 × 10⁵ cfu/g increased aerobic stability and ruminal in situ DM degradability of rehydrated corn grain silage. The addition of LPPA did not alter the fermentation process and worsened the aerobic stability of rehydrated corn grain silage. Further studies are warranted to confirm these conclusions in other corn hybrids, inoculants, and their combinations.     

Hardaliye: fermented grape juice as a traditional Turkish beverage

Twenty-six aged hardaliye samples, collected from different spots of the Kirklareli province of Turkey and hardaliye produced in laboratory conditions using the traditional method were investigated in this study. The pH ranged from 3·21 to 3·97. Red colour (Hunter Lab a_Lvalue) of samples ranged from 1·33 to 9·66. The total bacterial count ranged from 3·5×10²to 8×10⁵cfu ml⁻¹. The lactic acid bacteria counts of the samples were found to be between 1·0×10²and 4·0×10⁴cfu ml⁻¹. Yeasts and moulds, which were found in 21 samples out of 26, ranged from 1·0×10²to 8·1×10⁴cfu ml⁻¹. Coliforms and Escherichia coli were found in none of the samples. The changes of some microbiological and chemical properties of hardaliye during fermentation were investigated. The pH of hardaliye dropped from 3·86 to 3·39. The ethanol content of the end product was determined as 595·50 mg dl⁻¹. During the fermentation process, the total bacteria count, lactic acid bacteria count and yeast count changed from 2·1×10⁵, 6·0×10⁴and 1·2×10⁵cfu ml⁻¹to 1·3×10², 1·2×10³and 1·1×10³cfu ml⁻¹, respectively.Lactobacilli isolated from hardaliye samples were characterized by API 50 CH and other phenotypic criteria. A succession of Lactobacillus species, dominated by L. paracasei subsp. paracasei and L. casei subsp. pseudoplantarum were found during the fermentation process.     

Efficacy of phosphine and insect penetration ability in ZeroFly® bags

The deltamethrin incorporated woven polypropylene ZeroFly® storage bag is a promising novel technology for grain storage. However, if grain stored in ZeroFly bags gets infested and has to be fumigated using phosphine (PH₃), data on the effectiveness of such treatments are needed. Additionally, obtaining field data on ability of stored-product insect pests to breach ZeroFly bags would facilitate insect management. Therefore, efficacy of PH₃ in immature and adult Sitophilus zeamais (Motschulsky), Prostephanus truncatus (Horn), Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst) in experimental cages in maize stored in 100-kg polypropylene (PP), jute and ZeroFly bags was investigated. Post-fumigation mortality of adults was recorded after 7 d, and after 7 wk for immatures. The ability of either S. zeamais or P. truncatus to penetrate fabric of PP, jute and ZeroFly bags was assessed. Phosphine efficacy was good in all the three types of bags and resulted in complete mortality of adults and immatures of the four species tested. Sitophilus zeamais and P. truncatus were more successful in penetrating the PP bag fabric and on average made 84 and 780 holes per bag over a 4 mo-period, respectively; this was followed by jute with 37 and 614 holes. The ZeroFly bag was harder to breach and ≤3 holes per bag were made for both species. This study shows that PH₃ is highly efficacious in insects that infest maize stored in ZeroFly bags, and that these bags are not easily penetrated by stored product insect pests. Hitherto, ZeroFly bags are a good technology for storing grain that is not infested, and fumigation using PH₃ can be effectively conducted if infestation occurs. Therefore, ZeroFly bags can be incorporated in integrated stored product insect management (IPM) programs for bagged grains.     

Development and application of a sensitive,rapid, and reliable immunomagnetic separation-PCR detection method for Cronobacter spp.

Cronobacter spp. have been linked to clinical cases of infection in both adults and infants. Enrichment of Cronobacter spp. before detection has been necessary but is quite time consuming. Hence, we sought to develop an immunomagnetic separation (IMS) PCR method that could shorten the time of enrichment before the detection of Cronobacter spp. The polyclonal antibody used in this immunomagnetic separation was prepared based on the outer membrane protein A of Cronobacter sakazakii China Center of Industrial Culture Collection 21560 and had high specificity to the target. The primers used in the IMS-PCR method also showed high specificity. The detection limit of IMS-PCR for pure C. sakazakii culture was 5.2 × 10² cfu/mL. Cronobacter sakazakii in artificially contaminated powdered infant formula (PIF) was also detected at a detection limit of 5.2 × 10² cfu/mL. After 8 h of enrichment, the detection limit in PIF was lower than 5.2 × 10¹ cfu/mL. An interference test using Escherichia coli in artificially contaminated PIF showed that the IMS-PCR method developed in this study had a good ability to resist interference. Finally, the IMS-PCR method was applied to the detection of Cronobacter in food samples and was shown to be reliable. Thus, this newly developed IMS-PCR detection method was quite sensitive, rapid, and reliable and could be applied to the detection of Cronobacter in foods.