Shelf Life Period Research Articles

Does the Oxygen Permeability affect the Equilibrium Gas Concentrations in Passive Modified Atmosphere Packaged Pomegranate Arils?

The effect of oxygen permeability of packaging material on shelf life of minimally processed and passive modified atmosphere packaged pomegranate arils, cv “Wonderful” as well as some quality attributes were investigated. Packaging materials having Oxygen transmission rate (OTR) as low as 125–290 cm3/m2/day were found to provide the gas concentration requirements of 2–5% O2 and 3–10% CO2 for passive modified atmosphere application of fresh fruits and vegetables. Although color, firmness, anthocyanin, total phenolic content and sensorial and microbial properties significantly changed there was no significant change in pH, total soluble solids and antioxidant activity during storage period at 5C. Microbial counts of total aerobic bacteria did not exceed the legal limit during storage period but sensorial values were below the limit of threshold on 11th day of storage. OTR of packaging material of pomegranate arils should be as low as 125–290 cm3/m2/day under passive modified atmosphere and its shelf life was determined as 10 days at 5C and 90% Relative humidity (RH). Practical Applications The results of this project can be utilized by producers of fresh pomegranate arils to decide on packaging material having appropriate oxygen permeability. Thus the fresh cut producers prefer to use packaging materials having higher oxygen transmission rate since minimally processed fruits and vegetables are more susceptible to microbiological and sensorial deterioration because of the higher surface area leading to enhanced respiration rate. However, this situation is not valid for fresh pomegranate arils since the respiration rate of fresh pomegranate arils is lower compared to whole pomegranates. Producers will also get the opinion that shelf life period of fresh pomegranate arils is about 10 days and sensorial properties are more potent than the microbiological properties to determine the end of shelf life due to the nature of pomegranate arils.

Effects of aminoethoxyvinylglycine treatment by vacuum infiltration method on postharvest storage and shelf life of tomato fruit

The aim of this study was to determine effects of postharvest aminoethoxyvinylglycine (AVG) treatment using vacuum infiltration method on retardation of ripening, storage and shelf life of tomato fruit. In the Experiment-1, beefsteak ‘Grando F1’ tomato fruit was harvested at breaker stage and treated with AVG at six different doses (0, 62.5, 125, 250, 500 and 1000mgL−1) and three different vacuum pressures (0kPa, −20kPa and −30kPa) using vacuum infiltration method and kept at 20°C for 8d. The AVG treatment of 1000mgL−1 at −30kPa reduced ethylene production rate by 45.53%, delayed color changes and extended the number of days reaching to red ripe stage from 6 to 8 d at 20°C and was confirmed as the optimal treatment for the maximum retardation of tomato fruit ripening by response surface methodology. In Experiment-2, untreated and treated breaker ‘Grando F1’ tomato fruit with 1000mgL−1 at −30kPa were kept at 12°C for 0, 5, 10, 15 or 20d and for 2d at 20°C after cold storage. AVG treated fruit had lower ethylene production rate, lycopene content, a* and C* values and higher fruit firmness, chlorophyll content, L* and h° values, compared to control during storage and shelf life period. For shipping to distant markets, storage and shelf life of untreated fruit were 10d at 12°C plus 2 d at 20°C while AVG treatment extended storage and shelf life to 20d at 12°C plus 2d at 20°C.

Effectiveness of thin film application of imazalil fungicide on decay control of Tarocco orange fruit

For oranges intended for European markets, it is strongly advisable to find preservation methods increasing shelf-life and favouring the reduction of use of chemical antifungal products, both for reasons of environmental sustainability and to reduce the risk to health. In this paper results related to imazalil fungicide treatment of oranges fruits are reported. The experiments were carried out by comparing the traditional dipping of fruit with an innovative pilot plant process, designated “thin film” (TF), which is designed to reduce fungicide/water mixture concentration. Two film thickness (1 and 3 mm) and two temperatures (20 and 45 °C) were investigated. The incidence of decay was >5 mg kg−1 making the oranges unsuitable for the market. Therefore, TF treatment can be considered a useful method for maintaining high quality of citrus fruit and controlling green and blue mould both during cold storage and shelf-life period. A correlation was found between the overall decay incidence % and fungicide residue at time zero (adjusted R2 of 0.98) and the fungicide destruction rate logarithmically depended on its initial dose.

Performance check of particle size standards within and after shelf-life using differential mobility analyzer

In aerosol research, differential mobility analyzer (DMA) is widely used for particle size distribution measurements. In general polystyrene latex (PSL) particle size standards are used to calibrate the DMAs. However, these standards are expensive, and their shelf-life is limited. Therefore in this work, we have used PSL particle standard of sizes 60 and 100nm (SRM® 1964 and SRM® 1963a, respectively) and checked their performance within and after the shelf-life period for 3 consecutive years (2013 – 2015) using a calibrated DMA (i.e., long-DMA, TSI 3081). Also the size results are compared using a reference DMA (i.e., nano-DMA, TSI 3085). Using both long- and nano-DMA, the detail results of standard particle size measurements and involved uncertainties are discussed in this paper. We observed a continuous increase in the count mean diameter (CMD) calculated from the size distribution of each standard particle size with the progress of time. Particle size measured for PSL 60 and 100nm using long-DMA are (56.01±5.56)nm and (92.86±10.81)nm in 2013, (56.37±5.66)nm and (93.71±10.44)nm in 2014, and (57.42±5.84)nm and (94.79±9.68)nm in 2015, respectively. Whereas, these results when nano-DMA was used are (56.82±4.32)nm and (94.62±9.46)nm in 2014, and (58.08±4.98)nm and (95.15±9.12)nm in 2015, respectively. Uncertainty results show that the components which contribute significantly in total uncertainty (at k=2) in CMD measurements are DMA sheath flow rate, DMA calibration, difference in certified and measured diameter, and variation in the ambient temperature and pressure. The size measurement results obtained from long-DMA and nano-DMA agreed well. Based on the measurement results, we suggest that the increasing trend of particle sizes (CMDs) with the progress of time from 2013 to 2015 is possibly because of the coating of contaminant residues (present in the standard liquid suspension) on the surface of the PSL particles which is further observed by high resolution tunnelling electron microscope (HRTEM) images of particles. Particles standards are stable and well characterized more than two years even after their shelf-life within the uncertainty limits. Size performance results for PSL 60nm using calibrated long- and reference nano-DMA show good agreement with the size value given in the certificate, however standard PSL 100nm size is found to be underestimated by ~7%.

RETENSI FENOLAT BUBUR INSTAN FUNGSIONAL SELAMA PENYIMPANAN PADA SUHU RUANG

Fenolat retention of porridge instant functional for storage at room temperature. Has been done this study aims to determine the retention of instant porridge phenolics during storage as well as to determine the shelf life of instant porridge at room temperature. Estimation of shelf life or expiration period using the model of reaction kinetics. The treatment phase of the study include purple sweet potato flour manufacture, processing, instant porridge, instant porridge and storage at room temperature. Analysis of phenolics in instant porridge be done every 7 days for 56 days using UV-Vis spectrophotometry at a wavelength of 765 nm. The data obtained is used to determine the shelf life of instant porridge. The results obtained show the retention levels of phenolics on day 0 was 100% and at day 56 was 27.911% and the expiration of a functional instant porridge is 55 daysKeywords: Phenols, functional porridge, Fenolat Retention, Shelf Life, reaction kinetics model

KAJIAN RETENSI KAROTEN KAPANG ONCOM MERAH DARI TONGKOL JAGUNG SELAMA PENGOLAHAN DAN PENYIMPANAN MIE INSTAN FUNGSIONAL

Has done research on carotenoids retention oncom red on the processing and storage of instant noodles functional.This study aims was to determine the level of damage carotene in the instant noodle processing and to determine the carotene retention during storage of instant noodles as well as to determine the shelf life of instant noodles at a temperature 50ºC and 60ºC. Estimation of shelf life or expiration period using the model of reaction kinetics the treatment phase of the study include red oncom mold production, processing instant noodles and storage of instant noodles on the temperature. Analysis carotene on instant noodlesdone every 0 days to 6 days using UV-Vis spectrophotometry method in wavelength. The data obtained is used to determine the shelf life of instant noodles. The results obtained showed live carotene demage during the processing of instant noodles is to 20g = 1,867%. For temperature 60oC for 20g = 10,208%, and determining Q10 is 2,90 and the expiration of a functional instant noodles is 122 days.Keywords : Carotene, Mie Functional, Retention carotene, Shelf life, Reaction Kinetics Model

Impact of salicylic acid on the physiological and quality attributes of guava (Psidium guajava) fruits during storage at low temperature

Guava (Psidium guajava L.) fruits of cv. Allahabad Safeda were treated with salicylic acid (SA) or 5-sulfosalicylic acid (SSA) at 1 mM and 2 mM concentration and stored at 10oC for 12 days. After storage, fruits were transferred to ambient conditions for 3 days shelf-life stimulation period and then observations were recorded up to 12+3 days. Results revealed that fruits treated with SA or SSA at 2 mM concentration showed minimum weight loss and colour change but maintained maximum firmness, total phenolics and ascorbic acid content. Fruits treated with SA or SSA @ 2 mM also showed suppressed and/or delayed the respiration and ethylene production and minimum increase in SSC as compared to untreated samples. Hence, SA or SSA 2 mM can be effectively used for maintenance of desired post-harvest quality and extending the market life of guava fruits during storage at 10oC followed by 3 days of stimulated shelf-life period.

A mechanistic model to describe the effects of time, temperature and exogenous ethylene levels on softening of kiwifruit

Early harvested kiwifruit (Actinidia deliciosa (A Chev) Liang et Ferguson cv ‘Hayward’), from 14 growers and two seasons were stored under a wide range of storage temperatures (0–10°C) and exogenous ethylene levels (0–200μLL−1) followed by an ethylene free shelf life period at 0–20°C. Firmness levels were monitored using a non-destructive compression technique. A mechanistic model, based on a simplified representation of the physiology underlying fruit softening, explained 97% of the observed variation.The kinetic model parameters appeared to be generic for the 14 grower lines studied. Differences between the grower lines could be explained based on differences in the initial firmness levels and the initial amounts of active enzyme system present.The model was validated with independent experimental data on the softening of 70 batches of main harvest kiwifruit stored at 0°C, with more than 99% of the variation explained for each of the 70 grower lines. A further validation was done using literature data on shipping of “Kiwistart” fruit under dynamic temperature and ethylene conditions.

Metabolic activity, microbial growth and sensory quality of arugula leaves (Eruca vesicaria Mill.) stored under non-conventional modified atmosphere packaging

Arugula compositional characteristics linked to vitamin content, polyphenols and other health beneficial compounds have increased consumer interest to include it in the diet. This leafy vegetable is very susceptible to yellowing and dehydration, reducing its shelf life period. This study evaluated the effects of non-conventional modified packaging atmospheres, i.e. Argon (75–80% Ar+10–11% O2, balance N2), Nitrogen (10–11% O2+89–90%N2), High Oxygen (85–90% O2+10–15%N2), Helium (75–80% He+10–11% O2, balance N2) and Nitrous Oxide (75–80%N2O+10–11% O2, balance N2), on metabolic activity, microbiological growth and sensory characteristics of fresh cut arugula (Eruca vesicaria Mill.) leaves. The High Oxygen atmospheres reduced the respiration rate until 5days of storage, but there were no differences among treatments at the end of the storage period. There were no differences in ethylene emission among treatments at any of the evaluation dates. Non-conventional atmospheres had 0.5–1 log unit lower microbial growth counts than air packaging after 8days of storage. Color and sensory characteristics were not affected by the storage conditions. The non-conventional atmospheres maintained some quality characteristics of arugula leaves, suggesting it could be an alternative to conventional modified atmosphere used to maintain arugula shelf life.

The influence of Opuntia ficus-indica mucilage edible coating on the quality of ‘Hayward’ kiwifruit slices

The aim of this work was to study the effect of mucilage edible coating extracted from Opuntia ficus-indica (OFI) on the quality and shelf life maintenance of packaged kiwifruit slices. OFI mucilage alone or added with TWEEN® 20 were applied on kiwifruit fresh cut surfaces. After treatments, kiwifruit samples were stored under passive atmosphere at 5±1°C for 3, 5, 7 and 12days. At each storage period, visual quality and flavor score, pectin content, ascorbic acid and the microbiological characteristics were measured together with CO2 and O2 content in the packages. Kiwifruit slices coated only with mucilage or with mucilage plus Tween 20, showed a significant higher firmness and a lower weight loss than untreated slices, until 5 d of shelf life. No further differences in weight loss occurred after 7d of shelf life, while slices treated only with mucilage retained the highest firmness until the end of the shelf life period (12d). OFI mucilage alone had significant beneficial effects on the visual and flavor score of the kiwifruit slices, throughout the shelf life period. The treatment with Tween 20 did not affect the flavor of the kiwifruit slices, compared with untreated fruit. Although mucilage and partly tween 20 addition increased microbial growth, especially of yeasts, their levels were still below the threshold for yeast spoilage at the end of the monitoring period. Hence, the results showed that mucilage coating applied to kiwifruit minimally processed fruit improved the quality of stored fresh-cut kiwifruits.

Effects of rootstocks on storage and shelf life of grafted watermelons

Watermelon fruits from non-grafted or grafted ‘Crimson Tide’ (CT) and ‘Crisby’ (CR) onto Ferro, RS841, Argentario and Macis rootstocks were compared for their postharvest quality during storage at 7 °C for 21 days and additional 7 days at 21 °C. Non-grafted and grafted CT and CR fruits did not exhibit chilling injury (CI) symptoms, but the 1-2% of fungal decay occurred after shelf life period following storage. Watermelons grafted on Ferro and RS841 rootstocks had higher flesh firmness thicker rind, lower ripening rating, more intense (higher C*) brighter red (lower h° value) color and higher lycopene content after shelf life period following storage, compared to non-grafted fruits. All of the fruit tested by the panelists received high taste scores of >7.9 out of 8.5 at the beginning, but the scores decreased to >6.8 out of 7.7 at the end of shelf life period. Watermelons could successfully be kept for 21 days at 7 °C and additional 7 days at 21 °C. Watermelons grafted on Ferro and RS841 rootstocks had higher postharvest quality, compared to the non-grafted fruits for both cultivars.

Influence of type and shelf-life on two brands complementary food in color, vitamins, and sensory evaluation

The aim of our study was to measure the color by system CIELAB, sensory analysis, and determination of vitamins in children vegetable complementary feeding (carrot, vegetable mix) with the option to extend shelf life from eighteen to twenty-one months. Complementary children food was obtained from private factory in the Czech Republic. In this research there were used only carrot and vegetable mix samples. To determine the color changes by system CIELAB and determination of vitamins, samples of mash were analyzed before filling into jars and sterilization, and then immediately after sterilization. Further analyzes were performed for twenty-one months, with run of every three months (p <0.05). The comparison of color CIELAB parameter L* (lightness) for two process steps: raw mash and sterilized mash; there were significant differences when processing (p <0.0001, r2 = 0.9983). Mainly, the parameter L* (Lightness) showed statistically significant differences in carrot and garden mix (p <0.05). β-carotenes such as provitamin A, is in food of plant origin stable substance in the absence of air. Storing time had significant influence on contain of β-carotenes, the mean content during twenty-one months was 0.862 mg.100g-1 (p <0.05, r2 = 0.2300). There were no significant differences in dark storing (p >0.05, r2 = 0.1097). The sensory evaluation showed statistical differences in all descriptors (color saturation, uniformity of color, consistency and homogeneity) (p <0.05) in course of months of storage time and storage conditions (daylight-dark). The results can be recommended to manufacturers, extending the period of minimum shelf life of the required three months to twenty-one months due to instability as characteristics of color and textural properties which were obtained.

Effect of modified atmosphere packaging (MAP) on rachis quality of ‘Red Globe’ table grape variety

Rachis browning corresponds to a postharvest disorder that drastically reduces overall table grape quality. This problem has been associated mainly to water loss, but the possibility of having other factors involved like green pigment degradation and brownish compound synthesis that mask the green tissue is also feasible. Modified Atmosphere Packaging (MAP) is a technology used to extend table grape postharvest life, including rachis appearance. The objective of this study was to analyze the effects caused by MAP on rachis browning during cold storage of ‘Red Globe’ table grape variety. MAP helped to reduce the green color loss on rachises stored for 90days of storage at 0°C compared with a conventional storage (CS) even after a shelf life period, without to affect negatively the quality of the berries. Interestingly, MAP storage decreased the content of chlorophyll-a and increased the amount of pheophytin-a, a chlorophyll degradation product, compared to CS both after cold storage period and shelf life. Additionally, the expression of genes involved in the chlorophyll breakdown pathway was analyzed by qPCR. We found that MAP induced an increase in the transcript abundance of metal-chelating substance (MCS) and Red Chlorophyll Catabolite Reductase (RCCR) genes. However, Pheophytinase (PPH) and Pheophorbide-a Oxigenase (PaO) transcript accumulation revealed no changes compared with CS. Apparently, MAP generated a modification in the chlorophyll breakdown process allowing an accumulation of green like compounds responsible for the greener color of rachises in the MAP stored bunches. On the other hand, histological analysis reveals that after cold storage and shelf life, morphological changes and brown compounds accumulation take place at the periderm and cortex tissues, and these symptoms are less severe in MAP stored bunches helping to keep longer the green coloration of the rachises. In this study we observed that MAP storage increases rachis postharvest quality by reducing green color loss probably due to a combination of processes involving a delay of green pigments degradation and a less accumulation of brown compounds at the periderm and cortex tissues, thus preventing green pigments masking.

Tomato Fruit Marketability, Blossom-End Rot Incidence and Quality as Affected by Different Calcium Sources and Time of Application Under Calcareous Soil

Two field experiments were carried out during the winter seasons of 2011/2012 and 2012/ 2013 at The Experimental Farm of The Faculty of Environmental Agricultural Sciences, El-Arish, Suez Canal University, North Sinai Governorate, Egypt. The experiment aimed to study the effect of spraying tomato plants (Solanum lycopersicum) GS 12 cv. with different calcium sources (calcium chloride, calcium carbonate and calcium chelate as well as without calcium) at different times of application, viz, T1: spraying one time at full blooming, T2: spraying one time after 15 days from T1, and T3: spraying two times at T1 + T2 on marketable yield, unmarketable yield (expressed as fruits infected by blossom end rot (BER)), and quality of fruits after 10 days of beginning the storage period. Plants were grown under low tunnels. Spraying tomato plants with Ca+ as CaCl2 or CaCO3 and other Ca sources increased the marketable yield/ fed. , and also increased fruit shelf life period expressed as decreasing in fruit weight loss and increasing fruit firmness. Foliar application of CaCl2 recorded the lowest values of lycopene contents in both seasons. Time of calcium application did not reflect any significant effect on both marketable and nonmarketable yield as well as marketability (%) and BER incidence (%), and almost pH and TSS values. Application of T3 increased the fruit contents of vitamin C (V.C), while using T2 decreased the content of lycopene. All interaction treatments with control (without application of calcium) decreased marketable yield, marketability (%), but it increased unmarketable yield, BER incidence (%), fruit weight loss and TSS in the 2nd season. Therfore, spraying tomato plants grown under low tunnels in calcareous soil with Ca in different sources had positive effects on both marketable yield and blossom-end rot incidence, total yield, marketability%, BER% and on fruit quality after 10 days of storage period compared to control.

Evaluation of the risk of fungal spoilage when substituting sucrose with commercial purified Stevia glycosides in sweetened bakery products

The objectives of this study were to compare the effect of different Stevia-based sugar substitutes (S1–S3), sucrose alone and a mixture of sucrose+S1 on: (a) humectant properties, (b) relative colonisation rates of sponge cake slices at 0.90 aw by strains of Aspergillus flavus, Eurotium amstelodami, Fusarium graminearum and Penicillium verrucosum at 20 and 25°C and (c) shelf-life periods in days prior to visible growth. Results showed that sucrose, S1 commercial sugar substitute and the mixture of sucrose+S1 in water solutions were able to reach water activity levels similar to those of glycerol and glucose mixtures. The S2 and S3 commercial sugar substitutes were unable to reduce aw levels significantly. At 25°C, colonisation of sponge cake slices by E. amstelodami, A. flavus and P. verrucosum occurred in all the treatments. Growth of F. graminearum only occurred on sponge cake slices containing S2 and S3 Stevia-based products at both temperatures. The best control of growth (30days) was achieved in cake slices modified with sucrose or S1 Stevia treatments inoculated with A. flavus and in the sucrose treatment for E. amstelodami at 20°C. F. graminearum growth was completely inhibited when sucrose alone, S1 or sucrose+S1 treatments were used at both temperatures. This study suggests that, as part of a hurdle technology approach, replacing sucrose with low calorie sugar substitutes based on Stevia glycosides needs to be done with care. This is because different products may have variable humectant properties and bulking agents which may shorten the potential shelf-life of intermediate moisture bakery products.

A comparative assessment of long-term storage stability and quality attributes of orange juice in response to pulsed electric fields and heat treatments

Processing of orange juice by pulsed electric fields (PEF) and heat treatments was carried out to determine the quality variables during storage of 180 days at 4°C. Depending on the magnitude of applied electric field strength (13.82–25.26kVcm−1), energy (10.89–51.32J), in comparison with heat treatment (90°C for 10 and 20s); significant changes in pH, titration acidity, total dry matter, and browning index were found during the storage period. With no significant change in shelf-life period, the PEF processing better preserved orange juice quality than did the heat processing. Ascorbic acid content peaked with PEF-treated orange juice under the electric field strength of 17kVcm−1, the treatment time of 1034μs, and the energy of 17.37J through which no significant degradation occurred during the storage with the longest half-life (1112 days). Although ascorbic acid retention of the most of the PEF processed samples was higher than that of the heat processed ones; samples processed by 10.89, 12.70 and 29.57J energies resulted in lower ascorbic acid content than did the heat processing (90°C for 20s). Except for the samples treated by 43.99 and 51.32J energies on 180th day, the PEF processing led to no hydroxyl methyl furfural formation during and at the end of the storage, unlike the heat treatment.

Storage Temperature, Controlled Atmosphere, and 1-Methylcyclopropene Effects on α-Farnesene, Conjugated Trienols, and Peroxidation in Relation with Superficial Scald, Pithy Brown Core, and Fruit Quality of ‘d’Anjou’ Pears during Long-term Storage

Alternatives to ethoxyquin (Etq) are needed for controlling superficial scald of ‘Anjou’ european pears (Pyrus communis) during long-term storage. The current commercial standard storage conditions [Etq + −1 °C + controlled atmosphere (CA) with 1.5 kPa O2] reduced scald occurrence compared with control fruit (−1 °C + CA) during 6–8 months storage. At 1 °C in air, 1-methylcyclopropene (1-MCP) fumigation at 0.15 µL·L−1 at harvest was more efficient on reducing scald than Etq but did not prevent scald during 6–8 months storage. The 1-MCP-treated fruit at 1 °C in air developed their ripening capacity at 20 °C following 6–8 months storage but had deceased shipping ability (softening and yellowing of fruit). Although Etq inhibition of scald was associated with the inhibition of α-farnesene oxidation to conjugated trienols (CTols); 1-MCP reduced α-farnesene synthesis and thereby the availability of substrate to oxidize to CTols. CA storage at 1.5 kPa O2 totally prevented scald and retarded the loss of shipping ability without affecting the ripening capacity of 1-MCP-treated fruit at 1 °C through further decreases in the syntheses of ethylene, α-farnesene and CTols during 6–8 months storage. In addition, 1-MCP prevented a CA-induced disorder, pithy brown core (PBC), in ‘Anjou’ pears possibly through enhancing an oxidative/reductive metabolic balance during extended storage. In conclusion, the combinations of 1 °C + 1-MCP + CA is a potential commercial alternative to Etq for scald control while allowing the 1-MCP-treated ‘Anjou’ pears to recover ripening capacity during the shelf life period after 6–8 months storage.

Microbiological Quality of Soft, Semi-Hard and Hard Cheeses During the Shelf-Life

Abstract Cheeses as ready-to-eat food should be considered as a potential source of foodborne pathogens, primarily Listeria monocytogenes. The aim of present study was to determine the microbiological quality of soft, semi-hard and hard cheeses during the shelf-life, with particular reference to L. monocytogenes. Five types of cheeses were sampled at different time-points during the cold storage and analyzed for presence of Salmonella and L. monocytogenes, as well as lactic acid bacteria, Escherichia coli, coagulase-positive staphylococci, yeasts, molds, sulfite-reducing clostridia and L. monocytogenes counts. Water activity, pH and NaCl content were monitored in order to evaluate the possibility of L. monocytogenes growth. Challenge test for L. monocytogenes was performed in soft whey cheese, to determine the growth potential of pathogen during the shelf-life of product. All analyzed cheeses were compliant with microbiological criteria during the shelf-life. In soft cheeses, lactic acid bacteria increased in the course of the shelf-life period (1.2-2.6 log increase), while in semi-hard and hard cheeses it decreased (1.6 and 5.2 log decrease, respectively). Soft cheeses support the growth of L. monocytogenes according to determined pH values (5.8-6.5), water activity (0.99-0.94), and NaCl content (0.3-1.2%). Challenge test showed that L. monocytogenes growth potential in selected soft cheese was 0.43 log10 cfu/g during 8 days at 4°C. Water activity in semi-hard and hard cheeses was a limiting factor for Listeria growth during the shelf-life. Soft, semi-hard and hard cheeses were microbiologically stable during their defined shelf-life. Good manufacturing and hygienic practices must be strictly followed in the production of soft cheeses as Listeria-supporting food and be focused on preventing (re)contamination.

Controlled atmosphere maintains native and cultivated yerba mate quality during shelf life after long-term storage

Yerba mate shows social and economic importance for the Southern Latin American countries due to its easy production and large market range. However, there is a problem to harvest the yerba mate at the correct period and to store it until processing and marketing. Thus, the aim of this paper was to evaluate the interaction among the storage in controlled atmosphere, effect of cultivation form and shelf life period on yerba mate quality after long-term controlled atmosphere storage. The experiment was conducted in a factorial arrangement (3 controlled atmosphere conditions × 2 cultivation forms × 4 weeks of shelf life). Native yerba mate, stored under controlled atmosphere, showed higher chlorophyll concentration as compared to the cultivated one. Carotenoid concentration increased up to the third week of shelf life and thereafter remained constant, if the yerba mate was stored under ambient conditions. Oxygen partial pressure lowering allows long-term yerba mate storage, keeping its quality during four shelf life weeks at 20 °C. Controlled atmosphere is an efficient technique for yerba mate quality keeping during long-term storage and shelf life, allowing the harvest of the raw material at the correct period and the maintenance of its quality until processing and marketing. The cultivation form has a significant effect on the storage and shelf life potential of yerba mate stored under controlled atmosphere.

Evaluation of Alternative Preservation Treatments (Water Heat Treatment, Ultrasounds, Thermosonication and UV-C Radiation) to Improve Safety and Quality of Whole Tomato

Previously optimised postharvest treatments were compared to conventional chlorinated water treatment in terms of their effects on the overall quality of tomato (‘Zinac’) during storage at 10 °C. The treatments in question were water heat treatment (WHT = 40 °C, 30 min), ultrasounds (US = 45 kHz, 80 %, 30 min), thermosonication (TS = 40 °C, 30 min, 45 kHz, 80 %) and ultraviolet irradiation (UV-C: 0.97 kJ m−2). The quality factors evaluated were colour, texture, sensorial analysis, mass loss, antioxidant capacity, total phenolic content, peroxidase and pectin methylesterase enzymatic activities, and microbial load reduction. The results demonstrate that all treatments tested preserve tomato quality to some extent during storage at 10 °C. WHT, TS and UV-C proved to be more efficient on minimising colour and texture changes with the additional advantage of microbial load reduction, leading to a shelf life extension when compared to control trials. However, at the end of storage, with exception of WHT samples, the antioxidant activity and phenolic content of treated samples was lower than for control samples. Moreover, sensorial results were well correlated with instrumental colour experimental data. This study presents alternative postharvest technologies that improve tomato (Zinac) quality during shelf life period and minimise the negative impact of conventional chlorinated water on human safety, health and environment.