Dry ice as a novel chilling medium along with water ice for short-term preservation of fish Emperor breams, lethrinus (Lethrinus miniatus)

Emperor breams, lethrinus (Lethrinus miniatus) stored in a combination of dry ice and water ice at an optimum level of 20% and 50% were found to be in excellent condition up to 24 h without reicing. Total bacterial load ranged from 10⁴ to 10⁷ cfu/g, while total psychrophiles from 10² to 10⁴ cfu/g. Total lactics were found in the levels of 10¹ to 10² cfu/g. H₂S producers were detectable only on the 6th hour with a load of 10² cfu/g. Total coliforms and total anaerobic sulphite reducers did not show any consistent trend. TVB-N increased from 11.5 to 21.1 mg%, while TMA-N from 1.3 to 2.7 mg% in samples stored in the combination of dry ice and water ice. TVB-N and TMA-N in the samples stored only in water ice were found to be high. Hypoxanthine varied from 5.1 to 8.2 mg/100 g.     

Quantitative and qualitative studies on the bacteriological quality of Indian white shrimp (Penaeus indicus) stored in dry ice

Indian white shrimp (Penaeus indicus) stored in dry ice at the 1:1 ratio were found to be organoleptically suitable for consumption when they were stored for 24 h without reicing. Shrimp stored in water ice at the 1:1 ratio (as control) were acceptable up to 18 h. Shrimp stored in a combination of dry ice and water ice at the ratio of 1:0.2:0.5 were also found to be acceptable up to 24 h. Total bacterial load ranged from 10(6) to 10(9) cfu g(-1), while total psychrophiles ranged from 10(3) to 10(6) cfu g(-1). Total lactics were found in the levels of 10(2)-10(6) cfu g(-1). H(2)S producers were from 10(3) to 10(5) cfu g(-1). Lowest temperature of -4.8 degrees C was observed in shrimps stored in dry ice at 1:1 ratio. Bacterial flora associated with fresh raw shrimp were Aeromonas, Pseudomonas, Vibrio, Flavobacterium and Serratia. Aeromonas constituted 38% of the flora in raw shrimp. Flavobacterium (43%), Pseudomonas (47%) and Pseudomonas (38%) were the dominant bacterial flora in the shrimp stored in dry ice at 1:1 ratio, in the combination package, and in water ice at 1:1 ratio, respectively.     

Nucleotide degradation and biogenic amine formation of wild white grouper (Epinephelus aeneus) stored in ice and at chill temperature (4 °C)

Sensory (cooked and uncooked), chemical (proximate composition, TVB-N, nucleotide degradation products and biogenic amines) and microbiological quality (TVC and total coliform) changes were investigated during storage of ungutted white grouper kept in ice and at chill temperature (4 °C). According to the sensory assessment, the shelf life of white grouper was 16 days in ice and 4 days for fish stored at chill temperature. TVB-N values increased with storage time. Amines found in white grouper stored in ice were TMA, putrescine, cadaverine, 2-phenylethylamine, dopamine, agmatine, tryptamine and serotonin. Histamine, spermine, spermidine were never detected with either storage condition. The acceptability limit in terms of microbial count was exceeded at 8 days in ice and at 4 days for fish stored at chill temperature. Total coliform count was 2.8 log₁₀ cfu/ml at 1 day and reached 10⁵ cfu/ml for both storage conditions.     

Nonfermented ice cream as a carrier for Lactobacillus acidophilus and Lactobacillus rhamnosus

Efficiency of a nonfermented ice cream for delivering Lactobacillus acidophilus and Lactobacillus rhamnosus to consumers was evaluated. Both of the microorganisms survived at the populations of greater than 10⁷ CFU g^?1 during 12 weeks of storage at ?19 °C. Addition of the microorganisms had no significant effect on the overrun, viscosity, firmness and melting behaviour; it changed the acidity, pH and sensory properties of the finished product. Resistance to acid and sensitivity to bile of both bacteria were tested separately on fresh harvested cells before inoculation to ice cream and then on the frozen‐thawed cells after 12 weeks of cold storage in ice cream. Ice cream processing followed by cold storage reduced acid resistance of both bacteria at pH 2.5. Resistance to bile in L. rhamnosus was not affected in frozen‐thawed ice cream when compared to fresh cell, whereas resistance to bile in L. acidophilus appeared to be more susceptible to the process and cold storage.     

Efficacy of Sanitized Ice in Reducing Bacterial Load on Fish Fillet and in the Water Collected from the Melted Ice

ABSTRACT: This study investigated the efficacy of sanitized ice for the reduction of bacteria in the water collected from the ice that melted during storage of whole and filleted Tilapia fish. Also, bacterial reductions on the fish fillets were investigated. The sanitized ice was prepared by freezing solutions of PRO-SAN^® (an organic acid formulation) and neutral electrolyzed water (NEW). For the whole fish study, the survival of the natural microflora was determined from the water of the melted ice prepared with PRO-SAN^® and tap water. These water samples were collected during an 8 h storage period. For the fish fillet study, samples were inoculated with Escherichia coli K12, Listeria innocua, and Pseudomonas putida then stored on crushed sanitized ice. The efficacies of these were tested by enumerating each bacterial species on the fish fillet and in the water samples at 12 and 24 h intervals for 72 h, respectively. Results showed that each bacterial population was reduced during the test. However, a bacterial reduction of < 1 log CFU was obtained for the fillet samples. A maximum of approximately 2 log CFU and > 3 log CFU reductions were obtained in the waters sampled after the storage of whole fish and the fillets, respectively. These reductions were significantly (P < 0.05) higher in the water from sanitized ice when compared with the water from the unsanitized melted ice. These results showed that the organic acid formulation and NEW considerably reduced the bacterial numbers in the melted ice and thus reduced the potential for cross-contamination.     

Physicochemical and microbiological characteristics and mineral content of herby cacik,a traditional Turkish dairy product

Changes in the physicochemical properties, mineral and heavy metal content and microbial flora of cacik samples were studied over a storage period of 30 d. The analysis results were in the ranges as follows: dry matter content 16.45–20.76%, fat 1.45–4.30%, protein 8.14–13.87%, total ash 0.96–4.19%, salt 0.25–3.15%. There were significant differences in dry matter, fat, salt, protein and ash content of the cacik samples (P < 0.05). There were significant differences in Ca, P, Na, Mg, Cu, Fe, Zn and Mn content of the cacik samples (P < 0.05). Total aerobic mesophilic bacteria (TAMB) and enterococci reached levels above 10⁴ and 10³ CFU g^?1, respectively. Coliforms and Staphylococcus aureus were not detected in any of the cacik samples during the storage period. Lactic acid bacteria (LAB) on MRS and M17 agars were the dominant bacteria. The cacik samples had LAB counts up to 10^4.4 CFU g^?1. Copyright © 2005 Society of Chemical Industry     

Effect of calcium chloride addition on ice cream structure and quality

The influence of calcium fortification by the addition of calcium chloride on quality parameters of ice cream based on physical properties was investigated, as was the effect of κ-carrageenan at modifying the effects of this calcium fortification. Four ice cream mixes of conventional composition, with added κ-carrageenan (0 or 0.025%) and added calcium chloride (0 or 4.4 g L⁻¹ = 40 mM of added Ca²⁺), were prepared. Modulated temperature-differential scanning calorimetry was used to investigate the effect of calcium chloride on the nucleation temperature, enthalpy of melting, and freezing point depression. The protein composition of 15.4% (wt/wt) reconstituted skim milk powder solutions with or without 4.4 g L⁻¹ added CaCl₂ and in the supernatant after ultracentrifugation was determined. Fat particle size distributions in ice cream were characterized by light scattering. Ice crystal sizes before and after temperature cycling were determined by cold-stage light microscopy. The results demonstrated that the addition of calcium chloride led to a substantial increase in ice crystal sizes and in fat partial coalescence, which were exacerbated by the addition of κ-carrageenan. These results can be explained by the interaction between Ca²⁺ ions and casein micelles, rather than any effects on freezing point depression. The calcium ions led to a more compact micelle, less serum β-casein, and high fat destabilization, all of which would be expected to reduce macromolecular structure and volume occupancy in the unfrozen phase, which led to increased rates of ice recrystallization.     

Influence of gamma irradiation on growth and survival of Escherichia coli O157:H7 and quality of cig kofte, a traditional raw meat product

Cig kofte is a traditional Turkish food containing raw ground meat. Samples inoculated with Escherichia coli O157:H7 were irradiated at 0.5–6 kGy with a ⁶⁰Co source and stored at 4 and 25 °C. Total aerobic mesophilic count decreased with increasing irradiation doses, D₁₀ value was 0.83 kGy. Escherichia coli O157:H7 count decreased from 5.1 log₁₀ CFU g^?1 to an undetectable level (<1 log₁₀ CFU g^?1) after 1‐day storage at 4 °C following irradiation at 2 kGy, D₁₀‐value was 0.29 kGy. Irradiation doses up to 2 kGy did not affect sensory quality after 1 day. There was colour loss in samples irradiated at 2 kGy or above and stored for longer periods. Storage of the irradiated products at abused temperature must be avoided for safety assurance. Irradiation at 2 kGy has a great potential for extending the shelf‐life of cig kofte and assuring safety by decreasing the number of E. coli O157:H7 and other bacteria, but further studies with suitable package designs are needed to decrease quality degradation during extended storage.     

The evaluation of electrolysed water as an agent for reducing micro-organisms on vegetables

The efficacy of electrolysed oxidizing water in reducing micro‐organisms on vegetables was evaluated. Formation of brown spots on leafy and fruit vegetables could be avoided when they were soaked in acidic electrolysed oxidizing (AC) water for less than 9 and 15 min, respectively. Soaking in alkaline electrolysed (AK) water for 30 min did not affect the appearance of the vegetables. The effectiveness of water or AK water on aerobic plate count (APC) reduction was limited (0.5 log CFU g^?1). However, soaking in AC water alone effectively reduced APC values of leafy vegetables and fruit vegetables by 1.0–1.5 log CFU g^?1. Soaking in AC water followed by AK water further reduced APC by 0.5 and 0.7 log CFU g^?1 on leafy cabbage and green pepper, respectively. Continuous changing of electrolysed water with either shaking or ultrasonication can effectively reduce APC by 2–2.5 log CFU g^?1. Electrolysed oxidizing water was significantly more effective than water in eliminating micro‐organisms on vegetables.     

Fermentation characteristics,aerobic stability and ruminal degradation of ensiled pea/wheat bi‐crop forages treated with two microbial inoculants,formic acid or quebracho tannins

This study evaluated the effects of two commonly used microbial inoculants (Lactobacillus buchneri (LB) and Lactobacillus plantarum (LP)), formic acid (FA) and quebracho tannins (QT) on the fermentation quality, aerobic stability and in situ rumen degradation of pea/wheat bi‐crop forages. Precision‐chopped spring pea (Pisum sativum, var Magnus) and wheat (Triticum aestivum, var Axona) bi‐crops (3:1 pea/wheat ratio) harvested at a combined dry matter (DM) content of 301 g kg^?1 were used for the study. The bi‐crops were conserved without (Control) or with inoculants based on lactic acid bacteria (LB (10⁵ CFU g^?1 fresh weight (FW)) or LP (10⁶ CFU g^?1 FW)), QT (16 g kg^?1 FW) or FA (2.5 g kg^?1 FW) in laboratory silos of 1.5 kg capacity, with each treatment being replicated six times. The pH, chemical composition, aerobic stability and in situ rumen degradation of DM, nitrogen (N) and neutral detergent fibre (NDF) after 112 days of ensilage were measured. The average pH at silo opening was 4.0, suggesting that the silages were well fermented. There were no significant effects of additive treatment on water‐soluble carbohydrate, total N, soluble N, ammonia N and NDF. Lactic acid and acetic acid were the main fermentation products. High concentrations of acetic acid were found in all the treatments, indicating a heterofermentative pathway. Although FA treatment gave the most aerobically stable silage, the Control and QT‐treated silages did not heat up by more than 1 °C until after 6 days of exposure to air. There were no effects of additives on DM degradation characteristics. However, the inoculants increased the rate of N and NDF degradation in the rumen, and both FA and QT reduced the effective and potential degradation of N. © 2001 Society of Chemical Industry     

Effect of trehalose on the glass transition and ice crystal growth in ice cream

The effects of trehalose and sucrose on the rate of ice crystal growth in ice cream during accelerated shelf‐life were compared. Experimental and theoretical freezing curves were shown to be in good agreement. Glass transition temperatures (T_g) of maximally freeze concentrated trehalose and sucrose solutions (40% w/w) were found to be ?39.5 °C and ?47 °C respectively. For ice cream mixes, the T_g value increased from ?46.4 °C for the 100% sucrose‐based mix to ?42.0 °C for the 100% trehalose sweetened ice cream. However, no differences in viscosity, nucleation rate or inhibition of ice crystal growth were observed with increasing trehalose concentration in ice cream.     

The effect of filleting and ice application on the quality and safety of Atlantic bonito (Sarda sarda) at refrigerated storage

Filleting effect of refrigerated bonito with and without ice on the quality changes and food safety was investigated. Significant variations occurred (P < 0.05) in sensory, chemical and microbiological values amongst groups. The best sensory results were found for filleted bonito with ice (FBRI) with a shelf‐life of 13 days. While sensory values decreased significantly during storage, opposite situation occurred for both chemical and microbiological results (P < 0.05). The lowest total volatile basic nitrogen value was also observed with FBRI and was within the acceptable levels for 15 days as 17.86 mg 100 g^?1. All samples contained acceptable trimethylamine levels for 15 days despite unacceptable sensory values after certain days. Although filleting seemed to increase the lipid oxidation, ice application resulted in lowering thiobarbituric acid content. Histamine results closely supported sensory values in terms of legally permitted levels usually by set FDA. While WBR contained histamine value over EU permitted level as 113.78 ppm on the 7th day, the value for FBRI was 56.13 ppm on the 15th day. Histamine‐forming bacteria counts supported histamine formation in most groups, while total bacteria counts were in agreement with sensory results. This study suggests that using ice and filleting can improve shelf‐life of bonito stored at refrigerated temperatures in terms of food quality and safety.     

Survival of E. coli O157:H7 during manufacture of dry‐cured Westphalian ham surface‐treated with allyl isothiocyanate or hot mustard powder

BACKGROUND: Escherichia coli O157:H7 can survive commercial manufacture of some uncooked fermented meats. External application of microencapsulated allyl isothiocyanate (AIT) or hot (non‐deheated) yellow mustard powder was used to inactivate the pathogen during dry‐cured Westphalian ham manufacture. RESULTS: Within 45/80 days, E. coli O157:H7 numbers were reduced 5 log₁₀ CFU g^?1 by 400 µg kg^?1 AIT or 60 g kg^?1 mustard powder, but 80 days were required in the untreated control. Mustard powder but not AIT reduced numbers of lactic acid bacteria and staphylococci. Mustard powder or ≥ 300 µg kg^?1 AIT inhibited yeasts and moulds but did not affect ham pH or water activity. CONCLUSION: The commercial Westphalian ham process without AIT or mustard powder treatment was validated capable of reducing E. coli O157:H7 5 log₁₀ CFU g^?1. Surface treatments with ≥ 300 µg kg^?1 microencapsulated AIT or 60 g kg^?1 yellow mustard powder reduced the time required for this reduction by 40–50%. AIT volatility from microcapsules or hot mustard powder during application of these compounds may restrict their use in production facilities. Copyright © 2009 Society of Chemical Industry     

Effect of caffeic acid on haemoglobin‐mediated lipid and protein oxidation in washed cod mince during ice and frozen storage

BACKGROUND: Little is known about the relation between haemoglobin (Hb)‐mediated lipid and protein oxidation in muscle foods and how these two reactions can be inhibited by naturally occurring antioxidants. This study was aimed at evaluating (1) lipid oxidation and protein oxidation induced by 20 µmol L^?1 Hb during chilled and frozen storage of washed cod mince and (2) the efficiency of 10–1000 ppm (0.063–6.3 mmol L^?1) caffeic acid in preventing these reactions. RESULTS: Addition of 20 µmol L^?1 Hb increased peroxide value (PV), rancid odour, protein carbonylation, protein insolubilisation, redness loss and α‐tocopherol loss in ice‐stored washed cod mince. Since both lipid and protein oxidation developed at the same time, it was not possible to conclude which reaction initiated the other. All studied reactions were efficiently inhibited by ≥ 50 ppm caffeic acid, which could be a result of α‐tocopherol regeneration, general radical scavenging, reduced formation of oxidised Hb forms and/or conformational changes in Hb structure. During frozen storage the only clear effect of Hb was increased PV, and here caffeic acid was less efficient as an antioxidant. CONCLUSION: Hb‐induced lipid and protein oxidation occurred quickly in ice‐stored washed cod mince, and the two reactions could not be separated in time. During frozen storage, Hb caused only limited lipid oxidation. Caffeic acid (≥50 ppm) was an efficient antioxidant during ice storage. Copyright © 2010 Society of Chemical Industry     

Effects of inulin and oligofructose on the rheological characteristics and probiotic culture survival in low-fat probiotic ice cream

ABSTRACT:  The effects of supplementation of oligofructose or inulin on the rheological characteristics and survival of Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 in low-fat ice cream stored at –18 °C for 90 d were studied. Addition of oligofructose or inulin to ice cream mix significantly increased apparent viscosity and overrun and developed the melting properties in ice cream during storage ( P < 0.05). However, the highest increase in firmness, the lowest change in melting properties, and the longest 1st dripping time were obtained in probiotic ice cream containing inulin ( P < 0.05). Some textural properties have also improved especially by the end of storage. Freezing process caused a significant decrease in the viability of Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 ( P < 0.05). Oligofructose significantly improved the viability of L. acidophilus La-5 and B. animalis Bb-12 in ice cream mix ( P < 0.05). Although the viable numbers for both bacteria decreased throughout the storage, the minimum level of 10⁶ CFU/g was maintained for B. animalis Bb-12 in only ice cream with oligofructose during storage.     

Chemical properties and sensory quality of ice cream fortified with fish protein

BACKGROUND: Fish protein powder is a functional ingredient that can be used for enhancing the nutritional value of food products. In this study the effect of fortification with different levels of fish protein powder (FP) on chemical properties and sensory quality of Persian ice cream with 0, 30 and 50 g kg^?1 FP during storage at ? 18 °C for 4 months was investigated. RESULTS: Ice creams fortified with 50 and 30 g kg^?1 FP had significantly higher protein and solid‐non‐fat content than ice cream with 0% FP or 83, 69 and 51 g kg^?1 protein and 215, 204 and 181 g kg^?1 solid non‐fat, respectively. All products had the same levels of fat, lactose, acidity and pH. They had similar sensory quality after production except for colour, but sensory properties of fortified samples changed significantly after 2 months of storage. Colour faded, cohesiveness decreased, sandiness/coarseness increased, sweetness decreased and fish flavour and off‐odour increased. The control ice cream scored highest for additives odour and flavour. CONCLUSION: Development of ice cream fortified with fish protein powder could be an effective way to enhance nutritional and functional value of ice cream. But studies on storage stability, consumers' acceptance and attitudes are recommended if companies are planning to do so. Copyright © 2011 Society of Chemical Industry     

Characteristics of fibre‐rich powder and antioxidant activity of pitaya (Hylocereus undatus) peels

The contents of total dietary fibre (TDF), soluble dietary fibre (SDF), insoluble dietary fibre (IDF) and functional properties of fibre‐rich powders (FRP) from pitaya peels with different particle size (FRP80, FRP140 and FRP250) were determined. Results showed that FRP140 had higher TDF (79.37%) and SDF (33.07%) with a balanced ratio of SDF/IDF (1:1.32) and higher water‐holding capacity (54.20 g g^?1), swelling capacity (50.63 mL g^?1), oil‐holding capacity (2.65 g g^?1) and glucose dialysis retardation index (62.83% at 60 min), compared with FRP80 and FRP250. Therefore, physiochemical properties of FRP140 were further investigated. SDF of FRP140 mainly contained rhamnose (4.95%) and galactose (1.98%), with 9.45% galacturonic acid, while IDF dominantly contained xylose (4.76%) and galactose (3.42%), with 18.54% klason lignin. Total phenolic content was 7.75 mg g^?1 and mainly composed of salicylic acid (0.98 mg g^?1) and protocatechuic acid (0.45 mg g^?1). Furthermore, FRP140 showed significant reducing power, DPPH‐scavenging activity and nitrite‐scavenging ability.     

A new process for preparing transparent alkalised duck egg and its quality

When fresh duck (Anas plotyrhyncus) eggs (pH 8·0–8·5) are heated, their albumen develops a turbid gel. Through appropriate alkalisation (pH 11·5–12·8), the gel's transparency can be increased. The transparency of the heated duck egg-white is affected by pH value, heating temperature, heating rate and salt concentration. This research deals with the process for preparing the transparent alkalised duck egg and the change in its quality when stored. If fresh duck eggs are pickled in a solution of 42 g NaOH+50 g NaCl litre^?1 (25·3°C) for 8 days, removed, put in a water bath and heated at 70°C for 10 min they become transparent, their hardness and penetration increasing with storage. Total bacterial count and volatile basic nitrogen also increase with storage. The total bacterial count and the volatile basic nitrogen were 4·6 × 10⁶ cfu g^?1, 0·32 mg g^?1 when stored at a temperature of under 25°C for 4 weeks, respectively.     

Microbiological quality of fresh fruit and vegetable products in Catalonia (Spain) using normalised plate‐counting methods and real time polymerase chain reaction (QPCR)

BACKGROUND: Commercially available fruits and raw and ready‐to‐eat vegetables (n = 445) were examined for aerobic, coliform, and yeast and mould counts using normalised methods. Listeria spp., Listeria monocytogenes and Salmonella spp. were detected by real time polymerase chain reaction (QPCR) after enrichment. RESULTS: Aerobic plate counts ranged from < 10 to > 10⁹ colony‐forming units (CFU) g^?1, with the lowest and highest counts recorded for fruits and sprouts respectively. The highest incidence level of coliforms was found in ready‐to‐eat vegetables, with up to 65.7% of samples containing from 5 to 9 log₁₀CFU g^?1. Yeasts and moulds showed their highest incidence level between 5 and 6 log₁₀ CFU g^?1, with an overall range from < 2 to 9 log₁₀ CFU g^?1. Salmonella spp., Listeria spp. and L. monocytogenes were detected in 0.67, 2.7 and 0.9% respectively of the total samples examined. CONCLUSION: The samples analysed can be gathered into two main groups, one showing low microbial counts (fruits) and a second group (raw whole leaves and roots and packed ready‐to‐eat vegetables) with higher microbial contamination. Although incidence levels of pathogenic bacteria reported here are in the lower range of those reported elsewhere, positive detections highlight the importance of good hygienic measures throughout the whole food chain. Copyright © 2007 Society of Chemical Industry     

Isoflavone content in soy germ flours prepared from two drying methods

Isoflavone glucosides and aglucons in various soybean varieties (Chiang Mai‐60, S.J.‐5, Chiang Mai‐2, Srisumrong‐1, and Nakhonsawan‐1) harvested from dry vs. rainy seasons were quantified. Isoflavone contents of all soy germs ranged from 16.5 to 30.6 μmol g^?1. Regardless of varieties, isoflavone contents in germ of seeds from dry season were higher (P < 0.05) than those from rainy season. The Chiang Mai‐60 germ, having the highest isoflavone content (30.6 μmol g^?1), was selected for germ flour production. Freeze‐dried germ flour contained higher isoflavone aglucons (17.72 μmol g^?1 daidzein; 6.48 mg g^?1 glycitein; 4.28 μmol g^?1 genistein) than those (15.07; 5.59; 3.41) of drum‐dried germ flour. However, isoflavone glucoside contents in freeze‐dried germ flour (3.27 μmol g^?1 daidzin; 1.86 μmol g^?1 glycitin; 1.41 μmol g^?1 genistin) were lower than those (5.22; 3.15; 1.89) of drum‐dried germ flour. Total isoflavone contents of drum‐dried and freeze‐dried germ flours were comparable (34.32 vs. 35.02 μmol g^?1) but more than that (30.16 μmol g^?1) of unprocessed germ flour.