Combined effects of chemical dip and/or carrageenan coating and/or controlled atmosphere on quality of fresh-cut banana

The combined effect of chemical dip and/or edible coating and/or controlled atmosphere (CA) on quality of fresh-cut banana was investigated. Banana slices were subject to a 3-min dip into a solution containing 1% (w/v) calcium chloride, 0.75% (w/v) ascorbic acid and 0.75% (w/v) cysteine and/or combined with a carrageenan coating and/or combined with controlled atmosphere (3% O₂ + 10% CO₂). Physico-chemical and microbiological qualities were evaluated during 5 days of storage at 5 °C. Dip combined with CA treatment prevented product weight loss and increase of polyphenol oxidase activity during the 5 days of storage. Colour, firmness, pH, tritatable acidity and total soluble solids values and total phenolic content presented the smallest changes. Microbial analysis showed that minimally processed bananas were within the acceptable limits during 5 days of storage at 5 °C.     

The effect of the association of sanitizers and surfactant in the microbiota of the Cantaloupe (Cucumis melo L.) melon surface

This work aimed to evaluate the efficiency of 200, 500 and 1000 mg l⁻¹ of free available chlorine (FAC) and 60 mg l⁻¹ of peracetic acid (APA) associated or not with Tween 80 in reducing the mesophilic aerobes, coliforms group and fecal coliforms on cantaloupe melon surface. Also, the action of the organic chloramine in removing the Salmonella enteritidis when attached on the melon surface. All treatments reduced significantly (p<0.05) the microbiota analyzed when compared with a water washing, used as control. The treatment with 1000 mg l⁻¹ of organic chloramine with surfactant reduced the mesophilic aerobes (p<0.05) by 4-log cycles, more than the control. Also this chlorine solution was the most efficient in removing S. enteritidis after attachment of the microorganisms to the fruit surface, between 1 and 24 h.     

Microbiological quality of legume-based traditional fermented foods marketed in West Bengal,India

A total of 105 samples of six different types of legume-based popular fermented foods, namely amriti, dhokla, dosa, idli, papad and wadi, purchased from retail outlets in West Bengal, was analysed to determine their microbiological safety status. While dhokla and idli were of high-moisture foods (62 g (100 g)⁻¹), others had a lower moisture level (14–27 g (100 g)⁻¹). Papad was alkaline (pH 8.7), whereas all the other foods were acidic (pH 4.4–5.8). Every sample was found contaminated with total aerobic mesophilic bacteria (detection limit, 10 cfu g⁻¹); 38% (40/105) of the samples contained more than 10⁶ cfu g⁻¹. Aerobic mesophilic bacterial spores were found in 88% (92/105) of the samples (detection limit, 100 cfu g⁻¹), whereas their anaerobic counterparts were present in 39% (41/105) of the samples (detection limit, 10 cfu g⁻¹). Although all the samples, excepting one, were free from Staphylococcus aureus (detection limit, 100 cfu g⁻¹), 20% (21/105) of the samples were found contaminated with Bacillus cereus (detection limit, 100 cfu g⁻¹). Enterobacteriaceae were found in 46% (48/105) of the samples (detection limit, 10 cfu g⁻¹). Of the Enterobacteriaceae isolates, 92% were coliforms and 57% were faecal coliforms. Escherichia coli (detection limit, 10 cfu g⁻¹) was found in only one sample each of wadi and idli, at a load of 10³–10⁴ g⁻¹. Salmonella (detection limit, 1 cell (25 g)⁻¹) occurred in 12 samples of wadi, idli and papad, however was absent in the other three products. Clostridium perfringens (detection limit, 10 cfu g⁻¹) and Shigella (detection limit, 1 cell (25 g)⁻¹) could not be detected. The results obtained in the present study indicated that these foods were manufactured using poor-quality starting materials, processed under unhygienic conditions, or/and temperature-abused during transportation and storage. Based on these results, a guideline is recommended for obtaining safe products.     

The effect of packaging conditions on the quality of minimally processed celeriac flakes

The aim of the study was to select packaging conditions of minimally processed celeriac to preserve their quality during storage for 12 days at 4 and 15 °C. The quality of the product was determined on the basis of colour measured in the CIE L¹a¹b¹ system, sensory quality and total counts of mesophilic and psychrophilic bacteria, counts of moulds and yeasts, coliform counts, counts of Pseudomonas bacteria and the presence of bacteria from the genus Clostridium perfringens. Moreover, changes were determined in oxygen and carbon dioxide contents in the atmosphere within the packs, in which the product was stored. Celeriac flakes were packaged in the atmosphere with varying CO₂ contents (0%, 5%, 10%, 20%, 30%, 50% plus 2% O₂ and with balance N₂). After 12 days at 4 °C, it was found that celeriac flakes packaged in atmosphere containing 5% or 10% CO₂, 2% O₂ and balance N₂ were characterized by better quality than samples packaged in air atmosphere or in the atmosphere with CO₂ contents of 0% or higher than 10%. Modified atmosphere with the content of 5% or 10% CO₂, 2% O₂ and balance N₂, applied in the packaging of celeriac flakes, resulted in the inhibition of growth of mesophilic, psychrophilic and coliform bacteria in the tested minimally processed product.     

Synthesis and evaluation of some new demulsifiers based on bisphenols for treating water-in-crude oil emulsions

The present paper endeavors to synthesize nine types of demulsifiers based on bisphenols (bisphenol A (BA), bisphenol AC (BAC) and bisphenol CH (BCH)) having different ethylene oxide units (n = 27, 34, 45) namely; E (x + y) (where E represents BA, BCH or BAC and (x + y) which represents the ethylene oxide units (27, 34, 45)). The chemical structures of the prepared demulsifier were elucidated using FT-IR and ¹H NMR spectra. Effect of the chemical structure (hydrophobic and ethoxylated degree of hydrophilic parts) and the mechanism of demulsification process was investigated. The data were discussed on the light of the chemical structure of the demulsifiers and the factors, effecting the demulsification process. The efficiency of these demulsifiers was tested on water-in-oil emulsions (w/o) at different concentrations (100, 200 and 300 ppm), 7.4% asphaltene content and 30%, 50% and 70% water content. From the obtained data the best demulsifier was E(34)BA which shows 100% demulsification after 58 min at 30% water content and 300 ppm of the demulsifier.     

Superheated steam reduction of deoxynivalenol in naturally contaminated wheat kernels

Contamination of wheat with the Fusarium mycotoxin deoxynivalenol (DON) is a concern to the ethanol industry as it is stable during most processing operations and will be concentrated in the spent grains, which are potentially a valuable feedstock. Superheated steam at four processing temperatures (110, 135, 160, and 185 °C), three steam velocities (0.65, 1.3, and 1.5 m/s), and processing times of 2–15 min were used to treat wheat kernels naturally contaminated with DON to find the best processing parameters for the reduction of DON. A commercial enzyme-linked immunosorbent assay (ELISA) kit was used to determine DON levels in the wheat samples. Samples became increasingly toasted, displaying a brown color with increasing processing temperatures and times, and became friable after processing at temperatures of 160 and 185 °C. Only samples processed at 185 °C and 1.3 m/s exhibited any starch gelatinization. Significant (P < 0.05) reductions in DON levels were seen at 160 and 185 °C but were not generally seen at 110 and 135 °C and the effect of velocity was not significant (P > 0.05). Reductions of up to 52% were achieved at 185 °C and 6 min processing time and were due only to thermal degradation and not to solubilization and extraction.     

A survey on the microbiological and chemical composition of buffalo milk in China

One hundred and twelve samples of raw buffalo milk were collected at four locations in China, and their microbiological and chemical composition was analyzed. Average levels of major components were: fat 7.59% (v/v), crude protein 4.86% (w/w), lactose 4.74% (w/w), total solids 18.44% (w/w), ash 0.85% (w/w), and pH 6.65. The crude protein, fat, total solids and ash contents of milk from multi-crossbreed buffalo were higher than those of river buffalo’s, but lower than those of crossbreed F₁ and F₂ buffalo’s. Microbiological enumeration revealed counts of total mesophilic aerobic bacteria of 5.59 log cfu/ml, bacterial endospores 2.31, lactic acid bacteria 4.62, fungi 1.79, coliforms 2.42, Escherichia coli 1.53, and Staphylococcus aureus 1.68. Listeria spp. were below detection level in all of the samples. The microbiological quality of buffalo milk was judged marginal and indicates the need for improved hygienic standards.     

Non-thermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with a gas–liquid porous metal contactor

This study evaluated the effectiveness of a supercritical carbon dioxide (SCCO₂) system, with a gas–liquid porous metal contactor, for reducing Escherichia coli K12 in diluted buffered peptone water. 0.1% (w/v) buffered peptone water inoculated with E. coli K12 was processed using the SCCO₂ system at CO₂ concentrations of 3.1–9.5 wt%, outlet temperatures of 34, 38, and 42 °C, a system pressure of 7.6 MPa, and a flow rate of 1 L/min. Increased CO₂ concentrations and temperatures significantly (P < 0.05) enhanced microbial reduction. A maximum reduction of 5.8-log was obtained at 8.2% CO₂ and 42 °C. To achieve a 5-log reduction of E. coli K12 in 0.1% buffered peptone water, minimum CO₂ concentrations of 9.5%, 5.5%, and 5.3% were needed at 34, 38, and 42 °C, respectively. Further reductions of cells were observed after storage for 7 days at 4 °C. But storage at 25 °C increased the number of viable cells to 8-log cfu/mL after 7 days. This study showed the potential of the pilot scale SCCO₂ system with a gas–liquid porous metal contactor for microbial inactivation in liquid food.     

Occurrence of diacetoxyscirpenol (anguidine) in processed cereals and pulses in Turkey by HPLC

The purpose of this study was to investigate the diacetoxyscirpenol (DAS, anguidine) level of contaminated cereal and pulse products in Turkey. DAS was detected using high performance liquid chromatography (HPLC) with diode array detector (DAD) at 205 nm and suspicious the results for two specimens suspected to contain DAS were confirmed by gas chromatography–mass spectrometry (GC–MS). An acetonitrile–water (21 + 4, v/v) extract of the sample was cleaned up on a column packed with alumina/charcoal (0.35 g + 0.40 g). The minimum detectable amount of DAS was 16 ng/injection, limit of detection was 0.8 μg/g for HPLC. A total of 85 commercially available cereal and pulse product samples, collected from markets and street bazaars, were analyzed. The recoveries for corn flour with the known amounts of DAS (2, 3, 4 μg/g) were 85.3% (SD 4.81, n = 5), 98.1% (SD 12.6, n = 5) and 96.4% (SD 3.2, n = 5), respectively. DAS was detected in none of the cereal and pulse products.     

Effect of organic acids,hydrogen peroxide and mild heat on inactivation of Escherichia coli O157:H7 on baby spinach

Minimally processed baby spinach contaminated with Escherichia coli O157:H7 has been associated with multiple outbreaks of foodborne illnesses recently. Chlorinated water is widely used to wash vegetables commercially, but this washing procedure has limited efficacy and can lead to the formation of carcinogenic substances. This study was conducted to determine the effects of organic acids and hydrogen peroxide alone and in binary combinations with or without mild heat (40 and 50 °C) on the inactivation of Escherichia coli O157:H7 on baby spinach. Baby spinach leaves were dip-inoculated with E. coli O157:H7 to a level of 6 log CFU/g and stored at 4 °C for 24 h before treatment. Individual washing solutions (1% and 2% lactic acid [LA], citric acid [CA], malic acid [MA], tartaric acid [TA], acetic acid [AA], hydrogen peroxide [H₂O₂] as well as binary combinations of LA, CA, MA and H₂O₂ at final concentrations of 1% were used to decontaminate spinach leaves at 22, 40 or 50 °C for 2–5 min to test their efficacy in reducing E. coli O157:H7. Chlorinated water (200 ppm free chlorine) decreased the population of E. coli O157:H7 on baby spinach by only 1.2–1.6 log CFU/g, which was not significantly different from DI water washing. Washing with 1% LA at 40 °C for 5 min was the most effective treatment achieving a 2.7 log reduction of E. coli O157:H7 which is significantly higher than chlorine washing. Washing with LA + CA or LA + HP at 40 °C for 5 min was equally effective against E. coli O157:H7, resulting in a 2.7 log reduction of E. coli O157:H7. The application of mild heat significantly enhanced the efficacy of washing solutions on the inactivation of E. coli O157:H7. There was, however, no significant difference between treatments at 40 °C for 5 min and 50 °C for 2 min. The results suggested that the use of organic acids in combination with mild heat can be a potential intervention to control E. coli O157:H7 on spinach.     

Occurrence of deoxynivalenol (vomitoxin) in beer in Turkey detected by HPLC

The objective of this study was to investigate the deoxynivalenol (DON) contamination/level in beer consumed Turkey using high performance liquid chromatography (HPLC) with UV–visible detector at 220 nm. An acetonitrile–water (21 + 4, v/v) extract of samples first was cleaned up on a column packed with alumina–celite–charcoal (0.50 g + 0.25 g + 0.60 g) and the cartridge was washed with acetonitrile–water (21 + 4, v/v) for column condition and C₁₈ solid-phase extraction column was used for second clean up. The minimum detectable amount for the DON was 125 μg/l (2.5 ng injected). A total of 50 commercially available beer samples, collected from markets. None of the samples contained any detectable amount of DON. The recoveries for beer with the known amounts of DON (1 ppm) were 83.2% (SD 5.44, n = 5). This is a pioneering study performed in beer samples consumed in Turkey for the presence of DON.     

Emerging sanitizers and Clean Room packaging for improving the microbial quality of fresh-cut ‘Galia’ melon

This study evaluated how traditional or new sanitizers, alone, or in combination with the use of a Clean Room (CR), affected the respiration rate, microbial, nutritional and sensorial quality of fresh-cut ‘Galia’ melon. Melon pieces were packed in polypropylene trays under passive modified atmosphere (7.4 kPa O₂ + 7.4 kPa CO₂) and stored up to 10 days at 5 °C. The following treatments were performed: 150 mg/l chlorine (control) for 1 min; 80 mg/l peracetic acid (PAA) for 1 min; ozonated water (0.4 mg/l) for 3 and 5 min. The combinations of: ozonated water and PAA; 150 mg/l chlorine and packaging in CR; ozonated water for 3 min and package in CR; ozonated water for 3 min + PAA and packaging in CR were also studied. Throughout the shelf-life psychrotrophic, mesophilic, Enterobactericeae, lactic acid bacteria, moulds and yeast growth were determined. The use of PAA provided the lowest microbial load, but this sanitizer decreased the total vitamin C and the antioxidant activity. Nevertheless, the combination of PAA with 0.4 mg/l of ozonated water (3 min) could be a good substitute of use of chlorine. This treatment was effective in reducing the microbial counts, maintaining the antioxidant compounds and respiration rate and maintained the sensorial quality of the product during the 10 days at 5 °C. Treated product packaged in a CR did not show increased treatment effect, probably due to air quality in the laboratory. The use of CR just for the packaging of the melon pieces did not offer any additional advantage. However, the utilization of CR in an industrial environment during all processing steps (from washing to packaging) should be investigated for potential benefits.     

Reduction of coliforms in rice treated with sanitizers and disinfectants

The efficacy of commercial sanitizers and disinfectants to minimize the contamination of total mesophilic bacteria and coliforms in rice was investigated. Water treated rice showed 0.7 log CFU/g reduction of both total mesophilic bacteria and coliforms. Reduction in sanitizer-treated rice was even greater. Coliforms in rice treated with the sanitizers 24,000 ppm hydrogen peroxide, 250 ppm chlorine, 180 ppm quaternary ammonium compound (QAC), 350,000 ppm ethanol, and 2000 ppm calcium oxide were eliminated. The sensory properties of 250 ppm chlorine treated cooked rice did not differ significantly from the same properties of water treated cooked rice.     

Heat resistance of Bacillus cereus spores in carrot extract acidified with different acidulants

The effect of acidification of carrot extract on the heat resistance of Bacillus cereus (ATCC 7004 and 4342) spores was studied. Malic, acetic, citric, ascorbic, lactic and hydrochloric acids were used as acidulants. Thermal resistance experiments were performed over the range 82–108 °C with continuous monitoring of pH. Non-acidified carrot extract (pH 5.2) had a protective effect on the thermal inactivation of spores when compared with the reference McIlvaine buffer at the same pH value.Acidification of carrot extract reduced the D-values obtained for spores, this effect occurring whatever the type of acidulant used. For both strains and all treatment temperatures, as pH decreased the D-values decreased exponentially over the pH range studied (5.2–4.0), yielding straight lines, basically parallel, with an average slope of 0.203 ± 0.023.Significant decreases in survivor counts and apparent D-values were observed when injured spores were recovered using the usual recovery medium containing carrot extract.     

Application of slightly acidic electrolyzed water as a potential non-thermal food sanitizer for decontamination of fresh ready-to-eat vegetables and sprouts

The sanitization efficacy of slightly acidic electrolyzed water (SAEW) against food pathogens on selected fresh ready-to-eat (RTE) vegetables and sprouts was evaluated and compared to sodium hypochlorite (NaOCl) solution. RTE vegetables and sprouts were dip-inoculated with Escherichia coli (E. coli) and Salmonella spp. and dip-treated with SAEW, NaOCl solution for 5 min. SAEW treatment significantly (p < 0.05) reduced the total aerobic mesophilic bacteria from Chinese celery, lettuce and daikon sprouts by 2.7, 2.5 and 2.45 log₁₀CFU/g, respectively relative to un-treated. Pathogens were significantly (p < 0.05) reduced from Chinese celery, lettuce and daikon sprouts by 2.7, 2.8 and 2.8 log₁₀CFU/g (E. coli) and 2.87, 2.91 and 2.91 log₁₀CFU/g (Salmonella spp.), respectively following a SAEW treatment. SAEW and NaOCl solution showed no significant sanitization difference (p > 0.05). Results demonstrate that SAEW at low chlorine concentration and a near neutral pH is a potential non-thermal food sanitizer that could represent an alternative to NaOCl solution and would reduce the amount of free chlorine used in fresh-cut vegetables industry, since the same microbial reduction as NaOCl solution is obtained.     

Active film incorporated with sorbic acid on pastry dough conservation

Antimicrobial films, 25 and 70 μm-thick, incorporated with 0–6% of sorbic acid, were produced and layered with pastry dough without preservative to evaluate its antimicrobial action. Control pastry dough containing sorbate potassium was layered with low-density polyethylene films (LDPF). The sandwiches (films/pastry dough) were stored in LPDF bags at 8 ± 1 °C. The results of microbiological analyses obtained in the initial time for pastry dough with or without additive complied with the standards of the Brazilian current legislation. After 40 days of storage, the pastry dough layered with 70 μm-thick films, containing 3–6% of sorbic acid had significantly smaller microbial growth than, or equivalent to, the control pastry dough. Pastry dough with 25 μm-thick films, containing 6% sorbic acid, had the psychrotrophic count inferior to the control, and the aerobic mesophilic Staphylococcus spp. counts were 1 log cycle superior. The water activity and the moisture level showed no differences between the treatments throughout the storage time.     

Quality differences of whole ungutted sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) while stored in ice

The aim of this study is to determine the quality changes in whole ungutted sea bass and sea bream while stored in ice. Changes in chemical quality were determined by using pH, total volatile basic nitrogen (TVB-N, mg N/100 g), trimethylamine (TMA-N, mg/100 g), thiobarbituric acid (TBA, mg malonaldehyde/kg), water activity (a_w), color measurement, and sensory analysis. Changes in microbiological quality were determined by using the analysis of total viable mesophilic and psychrophilic bacterial counts. Result of this study indicated that the shelf life of sea bass and sea bream stored in ice as determined by overall acceptability sensory scores and microbiological data was 15 days.     

Effect of catechin and ferulic acid on melanosis and quality of Pacific white shrimp subjected to prior freeze–thawing during refrigerated storage

Melanosis of Pacific white shrimp (Litopenaeus vannamei) subjected to freeze–thawing with different thawing methods and various cycles were monitored during subsequent refrigerated storage (4 °C) up to 4 days. Melanosis score was lower in Pacific white shrimp thawed at 4 °C, compared with that found in samples thawed at room temperature or using tap water. Polyphenol oxidase (PPO) activity increased as freeze–thaw cycles increased (P < 0.05). Enhanced PPO activity was most likely associated with increased melanosis. Pacific white shrimp treated with catechin (0.05%, 0.1% and 0.2% (w/v)) or ferulic acid (1%, 2% and 3% (w/v)) and subjected to freeze–thawing with various cycles showed the retarded melanosis during the subsequent refrigerated storage of 4 days, compared with the control (P < 0.05). Treatment of shrimp with both phenolic compounds could impede the growth of psychrophilic bacteria and the spoilage as evidenced by the lowered psychrophilic bacteria count and total volatile base content (TVB). Sample treated with 0.2% catechin or 3% ferulic acid also exhibited the retarded lipid oxidation during the subsequent refrigerated storage, compared with the control (P < 0.05). Thus, either catechin or ferulic acid could be used as the potential additive to lower melanosis of shrimp with prior freeze–thawing.     

Antimicrobial efficacies of plant extracts and sodium nitrite against Clostridium botulinum

This study was conducted to evaluate the antibotulinal activities of some plant extracts, alone or in combination with nitrite (NaNO₂). Water- and 99.5% ethanol-soluble extracts (1:9 plant material weight-by-solvent volume, 25 °C, 48 h) of 90 kinds of fresh and dehydrated herbs and spices were tested. The aqueous extract of clove and alcohol extracts of lemon eucalyptus, mace and licorice exhibited greater antibotulinal activities in TPGY medium with MIC ranging from 0.05% to 0.2%. However in TPGY, only the aqueous extract of Coptis rhizome exhibited synergistic antibotulinal activity with NaNO₂, reducing the individual MIC of NaNO₂ from 6–8 ppm to 2 ppm with 0.05% Coptis extract. In a model meat food, the alcohol-soluble extracts of nutmeg (0.05%) and sage (0.02%), and the aqueous fraction of clove extract (0.05%) exhibited antibotulinal activities in combination with 10 ppm NaNO₂. The observed synergy between plant extracts and NaNO₂ that resulted in lower MIC of both additives have significant repercussion in the control of botulism in minimally processed meat products without compromising organoleptic properties.     

Microbiological evaluation of fresh-cut organic vegetables produced in Zambia

This study was undertaken to assess the microbiological quality of fresh-cut organic vegetables produced in Zambia. Fresh-cut organic mixed vegetables and green beans produced in Zambia were analysed for aerobic plate counts, coliforms, Enterobacteriaceae, Escherichia coli, Bacillus cereus, Clostridium perfringens, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and yeast and mould counts. The study included 160 samples for most of the parameters. The vegetables were grown on farms meant primarily for the export market. The vegetables were treated/washed with 150 μg ml⁻¹ chlorine solution at the processing plant prior to sampling. The aerobic plate count ranged between 3 log₁₀ and 9.7 log₁₀ CFU/g, with the highest count recorded for green beans. The largest grouping (26.1%) of vegetable samples fell between 3 and 4 log₁₀ CFU/g. Coliform counts were between 1.0 log₁₀ and 7.7 log₁₀ CFU/g. The highest incidence level was 31.4% for total coliform counts between 3 log₁₀ and 4 log₁₀ CFU/g. E. coli was only detected on mixed vegetables in the range of 0.6 log₁₀ to 3 log₁₀ CFU/g, while Enterobacteriaceae counts ranged between 1.6 log₁₀ and 9.8 log₁₀ CFU/g with the highest counts being found on green beans. The highest incidence level was of 25.8% for counts within the same range as the aerobic plate counts. Yeast and mould counts showed the highest incidence level between 5 log₁₀ and 6 log₁₀ CFU/g with an overall range between 1.5 log₁₀ and 5.6 log₁₀ CFU/g. L. monocytogenes, Salmonella spp. and S. aureus were detected in 20%, 23.1% and 83.9% of samples, respectively . C. perfringens and B. cereus were not detected in any of the samples analysed.