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Microbial Population of Shredded Carrot in Modified Atmosphere Packaging as Related to Irradiation Treatment
Abstract
Shredded carrots in modified atmosphere packaging were treated with low-dose irradiation of 0.5 kGy in order to determine whether additional reduction of microbial population would be achieved for carrots previously treated with chlorine. Commercially prepared shredded carrots treated with irradiation had a mean microbial population of 1300 CFU/g at the expiration date (9 days after irradiation) compared with 87,000 CFU/g for nonirradiated, chlorinated controls. Oxygen content of the headspace gas and ethanol content of the carrots were not significantly affected. Irradiation appears to be a suitable technology for shredded carrots.
... Para prolongar a vida-útil dos vegetais processados, outros métodos e técnicas estão sendo utilizados, como: a refrigeração, que reduz a taxa de respiração e senescência; o controle da umidade relativa, que minimiza a perda de água pelos produtos; embalagens com atmosfera modificada ou controlada, que também diminui a taxa de respiração e a senescência; aditivos químicos, para controlar alterações fisiológicas e reduzir a carga microbiana [35]; e o emprego da irradiação ionizante, tem mostrado um potencial efeito como tecnologia auxiliar na redução de perdas pós-colheita, manutenção da qualidade nutricional e efetiva na redução da população microbiana de produtos hortifrutícolas [14,18,20,23]. ...
... De acordo com NGUYEN-THE & CARLIN [25], CHERVIN & BOISSEAU [9] e BRACKETT [5] para cenouras comercializadas frescas e cortadas, as quais foram somente lavadas e desinfectadas com cloro, apresentaram uma contagem inicial de mesófilos da ordem de 10 6 UFC/g. HAGENMAIER e BAKER [14] em estudos com cenouras fatiadas observaram uma redução na contagem de mesófilos entre a amostra controle, que foi somente submetida as operações de lavagem e desinfecção, e a irradiada na dose de 0,45kGy de 13.000UFC/g para 200UFC/g, respectivamente. ...
... Minimally processed carrots consumed as ready to eat snacks or salad vegetables have become increasingly popular (Amanatidou et al., 2000;Barry -Ryan et al., 2000). Hagenmaier and Baker (1998) rinsed carrot with chlorinated water, removed the ends, cut into sections, shredded them (cross section 2.8 x 2.8 cm) and packaged. The resultant products were often less stable due to the enzymatic activity of the cut cell walls and due to the potential bacteriological contamination. ...
This study was undertaken to investigate the effect of pre- treatments, packaging and cold storage on shelf life of minimally processed carrots. Carrots were prepared by manual peeling, cutting, slicing and shredding and pre -treated in 1% citric acid, ascorbic acid, potassium meta bisulphite, egg albumin and 0.5% potassium sorbate solutions for 30 sec. prior to packaging. Pre-treated carrot pieces were surface dried in atmospheric air andpacked with a proportion of gases (5% oxygen, 15% carbon dioxide and 80% nitrogen) stored at 10°C. During storage, the chemical constituents and shelflife were analyzed. The results indicated that the whole peeled carrot without any pre - treatment had exhibited changes in the chemical constituents compared to other minimally processed carrots up to 45 days at 10°C.
... The total mesophilic aerobic microflora comprises a wide variety of microorganisms and may account for about 10 5 to 10 7 cfu.g -1 (Hagenmaier and Baker, 1998). The total mesophilic aerobic count (TAPC) is a measure of microbial quality of fruit juices (Iqbal, et al. 2015). ...
The present work aimed to evaluate, through thermal degradation kinetics (80 °C to 98 °C in time intervals of 0.5 to 25 min), the effects of different thermal treatments on the biochemical, physicochemical, sensory and microbiological parameters of two mixed fruit and vegetable pulps, a yellow and a red one. The evaluated fruit and vegetable pulps resulted from the mixture of different fruits and vegetables proportions (pineapple, beetroot, strawberry and lemon juice) added to a 50% (p/p) pear-based pulp to maximize their bioactivity, physicochemical stability and sensorial acceptance. Evaluated quality parameters included the determination of peroxidase activity (POD), pH, soluble solids content (SSC), total phenolic content (TPC), CIELab colour, sensory evaluation (colour, taste and aroma) and total mesophilic aerobic counts (TAPC). Regarding heat treatments optimization for both pulps with lower pH, it was concluded that higher temperature treatments (90 to 98 °C) applied over a shorter time (less than 5 min) were more effective to inactivate POD, to reduce the initial microbial load (>2 log10 cycles) and to maximize sensorial attributes. In both mix pulps, total phenolic content (TPC) was not significantly influenced by the different applied time-temperature binomials. From the degradation kinetic models and as an example, it was possible to conclude that POD followed a 1st order kinetic, where the temperature effect was well fitted to the Arrhenius equation. The results allowed to obtain optimized time-temperature binomials for each pulp to simultaneously achieve POD enzyme inactivation, microbial reduction, and maximization of quality parameters relatively to fresh pulps, 90 °C/5 min and 98 °C/2.5 min, for the yellow pulp and red pulp, respectively.
... The development of russet spotting without ethylene exposure is probably the result of endogenous production of stress ethylene. It is also known that irradiation, as a stress, can induce ethylene production in some fruits and vegetables (Abdel-Kader et al., 1968;Hagenmaier and Baker, 1998). Ethylene exerts its effect through binding to its receptors. ...
Irradiation of Iceberg lettuce was recently approved by the U.S. Food and Drug Administration (FDA) to enhance microbial safety and to extend shelf life at doses up to 4 kGy. However, the radiation tolerance of whole head lettuce is unclear. The present study was conducted to investigate the effects of gamma irradiation on the quality of Iceberg lettuce and explore means to reduce irradiation-induced disorders. Irradiation (0.5 and 1.0 kGy) induced symptoms similar to russet spotting and other discolorations (pink ribs, rusty brown, and vein browning) in both external and internal leaves during post-irradiation storage in air at 4 °C. Irradiation in the absence of oxygen or pretreatment with 1 ppm 1-methylcyclopropene had little effect on the irradiation-induced tissue discoloration. However, low oxygen atmosphere when maintained during the entire 14-day storage almost eliminated the disorders. Compared with non-treated control, irradiation created significantly lower headspace O2 and higher CO2 levels in the packages, indicating that irradiation promoted respiration. Our results suggest that modified atmosphere (MA) packaging could be used to mitigate irradiation-induced disorders in Iceberg lettuce.
... Combination with modified atmosphere packaging Combination with modified atmosphere packaging (MAP), refrigeration, freezing or cooking has great potential for improving the quality and the safety of fresh and processed foods [7,8,9]. Irradiation treatment reduces the numbers of patho-genic bacteria and the level of normal flora, while MAP suppresses the growth of the survivors during subsequent storage. ...
Purpose of the review: Combination of irradiation treatment with other preservation techniques is of potential importance in enhancing the effectiveness and reducing the energy or dose requirement for destroying food borne illness and spoilage organisms while retaining or improving product quality. Phytosanitary irradiation to control quarantine pests, particularly insects, in traded fresh commodities may also benefit from combination with other disinfestation techniques to enhance effectiveness, and to reduce costs, treatment time, and product damage. Main findings: Combined preservation treatments can be beneficial to eliminate pathogenic bacteria due to the synergistic or additive effect of the treatments. It also permits less extreme use of a single treatment which may protect the sensory quality of the foods. Combination with modified atmosphere packaging (MAP), refrigeration, freezing or heating has great potential for improving the quality and the safety of fresh and processed foods. Irradiation and heat treatments reduce the numbers of pathogenic bacteria and the level of normal flora, while MAP and cold suppresses the growth of the survivors during subsequent storage. The use of natural antimicrobials at concentrations that do not affect the sensory qualities can increase the relative sensitivity of bacteria by >4-fold and can reduce the radiation dose necessary to eliminate pathogens. Natural antimicrobials are normally not stable over time; microencapsulation and the use of edible coatings can improve stability of antimicrobial formulations and prolong their bioactivity. Phytosanitary irradiation doses to control insects (50 to 400 Gy) are relatively low compared to doses for food safety and sterilization applications. Lowering doses further could save money on treatment costs by reducing treatment time, increasing the capacity of irradiation facilities, and reducing any problems with commodity quality. Combining irradiation with other insect disinfestation modalities such as cold, heat, fumigation, modified atmospheres, and chemical insecticides is a possible means to reduce the radiation dose, and the duration, level, or concentration of the companion treatment while meeting the technical objectives of the quarantine treatment. Irradiation in combination with cold is particularly promising, as it may be a means to reduce the duration and therefore costs of current cold treatment protocols. Irradiation may also allow use of higher cold temperatures that do not cause chilling injury in cold-sensitive fruits.Directions for future research: The efficacy of active edible coating and active biodegradable packaging in combination with irradiation for microbial control needs further investigation and should be demonstrated at the industrial level. The use of combined treatments to eliminate viruses and parasites in food is not well studied and should be investigated. The effects of mild heat treatment before irradiation on insect radiotolerance and bacteria radiosensitization should be investigated. The relationship between MAP packaging and insect radiation tolerance needs to be explored for a wider variety of quarantine pest species, including surface pests and inherently tolerant Lepidoptera and mites. Additional research is needed to demonstrate the efficacy of irradiation plus cold combination treatments against insects in fresh produce while assessing commodity quality and the potential for commercial application.
... Irradiated (1 kGy) cilantro (Fan et al., 2003a) and lettuce (Fan et al., 2003b) showed some softening, but after a few days of storage, there was no significant difference between irradiated and nonirradiated samples. Other products, such as celery (Prakash et al., 2000), mushroom slices (Koorapati et al., 2004), and shredded carrots (Hagenmaier and Baker, 1998), also showed no change in firmness. ...
The ionizing radiation is known to effectively eliminate human pathogens such as E.coli on fresh fruits and vegetables, which can carry the potential risk of contamination. Fresh fruits and vegetables carry the potential risk of contamination because they are generally grown in open fields with potential exposure to enteric pathogens from soil, irrigated water, manure, wildlife, or other sources. The radiolysis of water generates free radicals, and these radicals, in turn, attack other components such as DNA in micro-organisms. The high radiation doses used in attempts to produce a sterile or shelf-stable fruit or vegetable commodity have resulted in unpalatable products. The low-dose irradiation is a reliable technology capable of killing human pathogens such as E.coli O157:H7 and Salmonella by 2-8 logs without causing significant deterioration in product quality.
... The mean microbial population after 9 days storage was much lower (1,300 CFU g -1 ) for irradiated shredded carrots (0.5 kGy) than for non-irradiated, chlorinated controls (87,000 CFU g -1 ) (Hagenmaier and Baker, 1998 ...
... Similarly, low-dose irradiation (0.15-0.50 kGy) of chlorinetreated fresh-cut carrots and iceberg lettuce reduced the total microbial counts by AU: Do we need to define this term? 70 or 700 times, respectively, as compared to nonirradiated chlorinated controls (Hagenmaier and Baker, 1997;Hagenmaier and Baker, 1998). ...
... É, empregada, ainda, para eliminar insetos e retardar o processo germinativo em alimentos de origem vegetal. Desta forma, há um aumento na segurança dos alimentos destinados ao consumo humano e uma redução nas perdas causadas por deterioração, além de aumentar do tempo de vida útil (Hagenmaier & Baker, 1998). ...
Buriti (Mauritia flexuosa L.), a typical fruit from the Northeast and Center-West Amazon of Brazil, is used in many regional dishes. It is considered an excellent source of carotenoids that are A vitamin precursors, showing a majority of β-carotene. It also presents ascorbic acid and sugar contents. Many studies have indicated that the lack of A vitamin is the main cause of night blindness and xerophthalmia. Also, ascorbic acid deficiency may cause scorbutic disease. The use of food irradiation is growing and represents an economic benefit to agriculture through the reduction of post-harvesting losses while maintaining food nutritional quality. In this study, Buriti in natura was treated with gamma irradiation with doses of 0.5 kGy and 1.0 kGy. The objective was to evaluate the irradiation effects on total carotenoids, ascorbic acid and sugars concentrations of Buriti. The fruit was evaluated through the total carotenoids analysis, by spectrophotometry, and the carotenoids (α and β-carotene and lutein), ascorbic acid and sugars were determined by High Performance Liquid Chromatography (HPLC). The results showed that buriti is an excellent source of total carotenoids (44600 μg/100g). The irradiation of buriti with the dose of 0.5 kGy did not significantly change carotenoids and sugars contents. However, there was a reduction of ascorbic acid concentration with an increase of the dose, which may have been caused by irradiation or by intrinsic and extrinsic factors that alter ascorbic acid stability in food, converting ascorbic to dehydroascorbic acid, while keeping the C vitamin active form.
... Atualmente, estão sendo desenvolvidas pesquisas com a finalidade de prolongar a vida-útil dos vegetais processados, como o emprego da radiação ionizante gama, que tem mostrado um potencial efeito como tecnologia auxiliar na redução de perdas pós-colheita, desinfestação de grãos, controle de microrganismos patogênicos e prolongamento da vida-útil em carnes, frutas e vegetais, desinfestação e maturação de frutas, inibição de brotamento em tubérculos e bulbos e manutenção da qualidade nutricional [18,20,21,24]. ...
This study aims was to evaluate the effect of low doses of gamma radiation on the total carotenoids, alpha and beta-carotene content in minimally processed carrots, during the shelflife. Carrots are the mains vegetable source of carotenoids provitamin A (alpha and beta-carotene). According to the Family Budget Survey (FBS) carried out in the Brazilian Southeast, within the roots and tubers group, carrots are widely consumed. The carotenoid stability varies largely during the stages of processing and storage, depending upon structure, temperature, oxygen availability, light exposure, humidity content, water activity and acid, metal anti-oxidant and pro-oxidant presence. The minimally processed carrots in this experiment were manually peeled, rinsed, cutted into diskis, packaged under 5% O2 / 10% CO2 and 21% O2 (sintetic air), gamma ionizing radiation treatments was carried out with a 137Cs source, of 0,25, 0,50, 0,75 and 1,0kGy doses, and shelf-stored at 5°C for 24 days. Total carotenoids quantification was by 449nm spectrophotometer. Determination of a and beta-carotenes was made by High Performance Liquid Chromatography (HPLC). The different treatments and control group were, too, evaluated by analysing of colour and volatiles, by gas chromatography/mass spectroscopy with solid phase microextration (CG-MS/SPME), for study the significant carotenoids losses during the process.
... The synergistic effect of cold storage with gamma radiation delayed the decay, extending the postharvest life of fruit irradiated at 1.0 and 2.0 kGy by eight days. For irradiated raspberry, pineapple (Damayanti et al., 1992), strawberry (Hussain et al., 2012) and plum (Hussain et al., 2013), the highest doses were more effective as they were of sufficiently high energy to disrupt the atomic and molecular components of the microorganisms (Hagenmaier and Baker, 1998). Thus, the highest dose resulted in the lowest pathogen survival and in a greater raspberry shelf-life. ...
Scientia Horticulturae j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i h o r t i a b s t r a c t Raspberries have short postharvest life and decay rapidly. A technology that is increasingly being used to inhibit the growth of these microorganisms and simultaneously delay fruit senescence is gamma ray irradiation. The aim of this study was to evaluate the effectiveness of this technology in cold-stored fresh raspberries postharvest and to find the best irradiation dose. Raspberries were purchased from a commercial orchard. The doses applied were of 0.5, 1.0 or 2.0 kGy, and the fruit was stored at 0 • C and 90% RH after the irradiation. Non-irradiated fruit was used as the control. The results indicated that the application of gamma rays did not alter the respiratory rate, ethylene production, flesh firmness, anthocyanins content or color index of the raspberries. The use of gamma radiation in doses of 1.0 and 2.0 kGy, associated with cold storage, extended the postharvest life of fresh raspberries by 8 days. The 1.0 kGy dose is considered the most useful one that reduces the decay incidence and weight loss and presents the lowest reduction in ascorbic acid. However, to recommend its use, it is necessary further studies about the effect of this dose in the bioactive and nutritional compounds of the raspberries.
... The synergistic effect of cold storage with gamma radiation delayed the decay, extending the postharvest life of fruit irradiated at 1.0 and 2.0 kGy by eight days. For irradiated raspberry, pineapple (Damayanti et al., 1992), strawberry (Hussain et al., 2012) and plum (Hussain et al., 2013), the highest doses were more effective as they were of sufficiently high energy to disrupt the atomic and molecular components of the microorganisms (Hagenmaier and Baker, 1998). Thus, the highest dose resulted in the lowest pathogen survival and in a greater raspberry shelf-life. ...
... É, empregada, ainda, para eliminar insetos e retardar o processo germinativo em alimentos de origem vegetal. Desta forma, há um aumento na segurança dos alimentos destinados ao consumo humano e uma redução nas perdas causadas por deterioração, além de aumentar do tempo de vida útil (Hagenmaier & Baker, 1998). ...
Buriti (Mauritia flexuosa L.), a typical fruit from the Northeast and Center-West Amazon of Brazil, is used in many regional dishes. It is considered an excellent source of carotenoids that are A vitamin precursors, showing a majority of β-carotene. It also presents ascorbic acid and sugar contents. Many studies have indicated that the lack of A vitamin is the main cause of night blindness and xerophthalmia. Also, ascorbic acid deficiency may cause scorbutic disease. The use of food irradiation is growing and represents an economic benefit to agriculture through the reduction of post-harvesting losses while maintaining food nutritional quality. In this study, Buriti in natura was treated with gamma irradiation with doses of 0.5 kGy and 1.0 kGy. The objective was to evaluate the irradiation effects on total carotenoids, ascorbic acid and sugars concentrations of Buriti. The fruit was evaluated through the total carotenoids analysis, by spectrophotometry, and the carotenoids (α and β-carotene and lutein), ascorbic acid and sugars were determined by High Performance Liquid Chromatography (HPLC). The results showed that buriti is an excellent source of total carotenoids (44600 μg/100g). The irradiation of buriti with the dose of 0.5 kGy did not significantly change carotenoids and sugars contents. However, there was a reduction of ascorbic acid concentration with an increase of the dose, which may have been caused by irradiation or by intrinsic and extrinsic factors that alter ascorbic acid stability in food, converting ascorbic to dehydroascorbic acid, while keeping the C vitamin active form.
... Shredded carrots show serious problems of shelf-life. Microbial increase observed during conservation is responsible of numerous degradation processes: slime formation, loose firmness and off-odors favored by cutting operations and by other technological processes (Carlin et al., 1990;Babic et al., 1992;Rossi et al., 1997;Torriani and Massa, 1994;Hagenmaier and Baker, 1998). On the basis of these considerations the aim of this work has been both to evaluate the microbial conditions of stick carrots at retail and to individuate the points of microbial hazards during the production process and which microorganisms can be considered as quality indicators. ...
The microbial composition of ready-to-use carrots, either marketed or during processing, was investigated with the aim to establish which microorganisms can be used as indicators of microbial quality. In all samples the mesophilic aerobic bacterial count, evaluated at half of shelf life was considerable (about 107 CFU/g) and composed mainly by Gram negative rods belonging to Pseudomonas and Enterobacter genera; similar values were observed for Leuconostoc mesenteroides. During the production process, the most critical point for Gram negative rods was represented by the range of time after dressing operations and before packaging. On the contrary the number of Leuconostoc sp., continuously increased during processing. On the basis of the obtained results, it is reasonable to consider the Gram negative rods and Leuconostoc sp. as potential markers of microbial quality of MPF carrots not only because of their high numerical values and constant presence, but also for their enzymatic activities.
... To reduce the microbial population of shredded carrots stored at refrigerated temperatures, further hurdles, to be used singly or in combination, were proposed, i.e. modified atmosphere packaging (MAP), irradiation and disinfection with various sanitizers (Nguyen-the and Carlin, 1994; Chervin and Boisseau, 1994; Hagenmaier and Baker, 1998). However, most of these treatments are not permitted in all the European countries and MAP favours the growth of undesirable obligately heterofermentative lactic acid bacteria. ...
Forty leuconostoc strains from commercial ready-to-use shredded carrots were characterized by physiological and genetic tests. Most of them were identified by RAPD- PCR as Leuconostoc mesenteroides subsp. mesenteroides, two strains as Leuconostoc ci- treum and one as Leuconostoc pseudomesenteroides. Using in vitro antagonistic assays, it was demonstrated that leuconostoc isolates were inhibited by selected strains of faculta- tively heterofermentative lactobacilli able to produce antimicrobials; Lactobacillus plan- tarum IMPC LP4 showed the strongest inhibitory activity. Its application as inoculant in shredded carrots was effective in controlling the growth of leuconostocs, possible cause of deterioration during storage. This hurdle could readily be combined with low temperatures to reduce microbial spoilage risk of ready-to-use carrots.
... After equilibration of the apple slice temperatures, respiration rate and ethylene production were measured using a closed system. 14 Changes in CO 2 and O 2 concentration in the headspace of the jars over 3 h were measured with a gas chromatograph (Fisher Gas Partitioner, Model 1200, Fisher Scienti®c, Spring®eld, NJ) equipped with a thermal conductivity detector. Column and injector temperatures were 90 and 135 °C respectively. ...
Respiration and ethylene production rates of irradiated apple slices from four apple cultivars were measured for 72 h. Doses less than 1.2 kGy had no effect on rates of CO2 production and O2 consumption, and irradiation at doses between 1.2 and 2.4 kGy had minimal effect for all cultivars. Respiratory response of ‘Idared’, ‘Law Rome’ and ‘Empire’ slices to irradiation was curvilinear, with maximum respiration occurring in the 3–6 kGy dose range. Response of ‘Delicious’ slices was linear over the irradiation dose range (0–11 kGy) studied. Respiratory quotient increased with irradiation dose. The degree of maturity of the slices affected respiratory responses. Irradiation reduced ethylene production of all slices. These results suggest that irradiation doses of up to 2.4 kGy can be used with minimum effect on the respiratory physiology of tissues.© 2000 Society of Chemical Industry
... Chervin and Boisseau (1994) reported that irradiation of shredded carrots was superior to chlorination and spin-drying. Microbial populations (measured as total plate counts) of shredded carrots treated with 0.5 kGy or chlorine and stored 9 days under refrigeration were 1300 and 87,000 CFU/g, respectively (Hagenmaier and Baker, 1998b). The same authors reported a similar reduction of microbial populations on cut iceberg lettuce treated with 0.19 kGy (Hagenmaier and Baker, 1997). ...
Fresh-Cut Products Food Safety Systems in the Fresh-Cut Produce Industry Fresh-Cut Produce Production Potential Microbial Risk of Fresh-Cut Product Operation Strategies to Reduce or Eliminate Hazards in Fresh-Cut Products Conclusions References
A irradiação de alimentos tem se mostrado eficiente em relação ao controle de patógenos em alimentos minimamente processados e no aumento do tempo de prateleira destes produtos. O presente trabalho teve como objetivos avaliar a ação de diferentes doses de radiação e temperaturas de armazenamento em cenoura minimamente processadas, pré-cozidas e embaladas a vácuo. As amostras foram submetidas à radiação gama em fonte 60Co Multipropósito no Instituto de Pesquisas Energéticas e Nucleares nas doses 0 kGy (testemunha); 1,0 kGy; 2,0 kGy e 3,0 kGy e armazenadas em temperatura ambiente, geladeira (5°C±1°C) e freezer (-18°C±1°C). Os parâmetros físico-químicos analisados foram: teor de sólidos solúveis, acidez titulável, pH, cor, carotenoides totais e firmeza. Essas análises foram feitas uma vez por semana durante o período de três semanas. O método estatístico utilizado foi análise de variância (nível de significância de 5%), seguidas do teste de Tukey. Constatou-se que o uso do processo de irradiação, para a maioria dos casos, não afetou significativamente os parâmetros físico-químicos das amostras analisadas. A acidez titulável e o pH foram os parâmetros mais influenciados pelo uso das diferentes doses de radiação ao longo do período de armazenamento. Observou-se aumento nos valores de pH nos tratamentos com doses de radiação. As temperaturas de armazenamento mais baixas (geladeira e freezer) foram mais eficientes para a manutenção das características dos produtos ao longo do período de armazenamento. No geral, as doses de 1kGy e 3kGy foram as que apresentaram valores mais próximos aos da testemunha para os parâmetros analisados.
For increasing the shelf-life of carrot slices during storage, a bioactive edible coating was applied. An antimicrobial nanoemulsion (composed of citrus extract, cranberry juice and essential oils) was incorporated into a calcium caseinate (Ca-Cas)-based encapsulation matrix. Gamma-irradiation at 32 kGy was evaluated for its ability to improve the physicochemical properties of the coating via Ca-Cas cross-linking. Irradiation of Ca-Cas was found to be effective in preserving the mechanical properties of the coating containing the nanoemulsion. Pre-cut carrots were then subjected to different coatings applied alone or combined to gamma-irradiation post-treatment at 0.5 kGy. The quality and the shelf-life of carrot were assessed by evaluating the weight loss, texture and color of carrots as well as their microbial quality. The combined treatment of bioactive coating with irradiation showed a synergistic potential and a higher efficiency to extend the shelf-life of carrots and maintain their quality throughout storage, compared to single treatments.
Fresh-cut produces, initially called minimally processed or lightly processed produces, are those that have been trimmed and/or peeled and/or cut into 100% usable product that is bagged or prepackaged. In particular, fresh-cut products attract consumers because they are fresh, nutritious, reasonably priced, and less time-consuming. As a consequence, a wide assortment of fresh-cut produces has been developed to meet consumer’s needs for “quick” and convenient products. With the busy lifestyles, consumer tends to use less time for preparing meals. Consumers prefer eating fruits and vegetables, and they prefer ready-to-eat products than preparing it themselves. As a result, the maintenance of the quality of fresh-cut produce has become more challenging to the food industry today.
Vegetable products, including fresh produce, pre-cut salad vegetables, and fresh juices, typically receive only minimal processing. Often eaten raw or only lightly cooked, these commodities play an important dietary role in many societies.
The fresh-cut fruit and vegetable market has grown rapidly in recent years with justifiable expectations of continuous growth. On the other hand, such products are still under study in order to improve the quality, safety, and, in particular, the shelf life of the products to fulfill consumers’ expectations. Numerous applications of recent science and technologies have been made in an attempt to prolong the shelf life of these products. Extended shelf life in foods has traditionally been linked with thermal processing by inactivating food spoilage and pathogenic microorganisms. Heat treatment, however, leads to destruction of freshness and nutrient loss. One of the promising approaches being considered is to utilize nonthermal technologies that, to some extent, achieve freshlike quality and a safe product with high nutritional value. This chapter reviews updated contributions regarding the minimal processing of plant food products in order to maintain and achieve freshness and longer shelf life. Special attention is given to the newest trends in nonthermal technologies for fresh-cut fruits and vegetables.
Foodborne illness (FBI) outbreaks in the United States associated with contaminated fruits, vegetables, salads, and juices have prompted redoubled efforts to improve agricultural, postharvest, and supply-chain controls that reduce risk. However, the lack of a broadly applicable antimicrobial process (a "kill step") suitable for use by the fresh produce industry is hampering food safety efforts. New tools to ensure the safety of fresh and fresh-cut produce are required; low-dose irradiation is one of the more promising of these tools. The US Food and Drug Administration (FDA) recently approved irradiation as a safe and effective means of improving the safety and quality of Iceberg lettuce and spinach. This chapter will summarize the science related to food irradiation as it is applied to fresh and fresh-cut fruits and vegetables for food safety purposes. This edition first published 2013 © 2013 Blackwell Publishing and the Institute of Food Technologists.
Since ready-to-use (RTU) products are not fully cooked, the shelf-life of the product is comparably short and the products are easily spoiled when contaminated with food-borne pathogens. Low-dose gamma irradiation of 0.5, 1, or 2 kGy effectively reduced the total aerobic bacterial counts in 2 Korean manufactured RTU products by 1.63 to 2.95 log CFU/g during cold storage. Irradiation at 2 kGy reduced the psychrotrophic bacterial counts in most of the samples to below the limit of detection (
A cenoura é uma das principais hortaliças consumidas no Brasil, pois além de possuir um sabor agradável muito apreciado pelos brasileiros também é uma grande fonte de carotenóides, fibras, vitaminas, minerais e outros componentes bioativos, dos quais o de maior destaque é o β-caroteno. Ela pode ser consumida crua ou cozida na salada ou ainda ser processada em vários produtos tais como: suco de cenoura, muitas vezes misturada com algum tipo de fruta; cenoura minimamente processada; cenourete e catetinho; cenoura desidratada entre outros. Tais processamentos além de agregar valor ao produto final, também permitem que certas partes da cenoura que anteriormente seriam descartadas possam ser utilizadas garantindo a qualidade e sabor característicos dessa hortaliça. O objetivo deste trabalho foi realizar uma revisão bibliográfica abrangendo desde a importância da cenoura na dieta até as pesquisas mais recentes sobre este tema e dos tipos de processamento mais utilizados. Foi possível observar que a cenoura desempenha uma atividade nutracêutica, sendo uma das principais e mais consumidas fontes de carotenóides na dieta humana
Irradiation can serve as a hurdle step in an overall safety plan that enhances safety while preserving quality of fresh-cut fruits and vegetables. Extension of shelf-life using irradiation is primarily due to the decrease in spoilage organisms, thus the effectiveness of irradiation depends on initial quality of the product. Irradiation at the levels optimal for shelf-life extension is also effective against pathogens found in fresh produce. Vegetative pathogens are destroyed while background flora is reduced but not eliminated. Combining irradiation with other technologies such as calcium treatment, warm water dips, and modified atmosphere packaging can further enhance shelf-life and mitigate adverse effects on quality.
Fresh-cut (minimally processed) fruit and vegetable sales have grown to approximately $12 billion per year in the North American foodservice and retail market and account for nearly 15% of all produce sales. Modified atmosphere packaging (MAP) systems are used extensively for fresh-cut fruit and vegetable products to extend shelf-life by reducing; water loss, respiration rates, cut surface browning, microbial growth, ethylene (C2H 4) biosynthesis and C2H4 action. Effective and efficient design of MAP systems for fresh-cut produce requires prerequisite information such as; produce respiration rates among various temperature ranges and atmospheres, determination of what atmospheres will provide benefit and what atmospheres may induce accelerated physiological or microbial decay. Since the CA '97 conference, a significant amount of information has been generated for fresh-cut fruit products, which are perceived to be the next great business opportunity in fresh-cut produce. This paper summarizes the published scientific information related to the use of MAP and fresh-cut produce. The recommendations contained in this paper are a starting point for fresh-cut MAP system design and must be tailored to the unique processing, storage, distribution and marketing for a specific product.
This chapter reviews the application of irradiation alone or in combination with other treatments to preserve some fruit and vegetables, fish, poultry, and meat. Irradiation processing is a safe and effective process to control food-borne disease. This process has the advantage that it can be applied under fresh conditions and on packed foods. The development of combined treatments with irradiation is attractive because it will enhance product safety and offer a higher quality product. It will also provide the opportunity to introduce new food products to the food market. However, more research is needed to evaluate the mechanism of action of each treatment on the most important pathogens found in each type of food to optimize the treatment. The use of irradiation for decontamination of foods is a promising technology that can be applied to the product. This technology can also be applied to fresh, frozen, or cooked products. It is a physical, safe, environmentally clean, and efficient technology.
Minimal processing allows consumers to have fresh like quality fruits and vegetables with convenience. Minimal processing operations like cutting, slicing, chopping, peeling, etc. cause injuries to the plant tissues and initiate enzymatic changes. As the tissues are still living these operations cause ethylene production, respiration, accumulation of secondary metabolites and water loss from tissues and make them more susceptible to microbial spoilage. The tissue response to cutting depends on the type of cultivar, physiological maturity of the fruit or vegetable and pre-harvest crop management. However, due to continued respiration and enzymatic activity, minimally processed fruits and vegetables suffer changes in nutritional value and sensory quality like loss of texture, appearance and flavour during storage. Minimally processed fruits and vegetables offer a good media for the growth of microorganisms and a number of pathogenic microorganisms are reported to grow over them. A number of preservative methods have been used for minimally processed fruits and vegetables like addition of texture improvers, antibrowning agents, acidulants, antimicrobial agents, reduction in aw and mild heat treatments combined with modified atmospheric packaging and refrigerated storage. Use of ionizing radiation and novel non-thermal preservative technologies like high pressure and pulsed electric field have shown promising results in producing high quality and safe minimally processed products.
Se realizó una investigación bibliográfica que se trazó como objetivo general evaluar el estado de las investigaciones, la producción y el consumo de alimentos vegetales listos para consumir en el mundo. Para la recopilación de la información se hizo uso de bases de datos de alimentos, sitios web y publicaciones de revistas especializadas en el tema. Los resúmenes y artículos científicos publicados desde 1996 a 2006 fueron clasificados por períodos y temáticas de investigación. Para el almacenamiento de la información se hizo uso del programa Endnote para la creación de una biblioteca virtual. Se evaluaron los autores e instituciones líderes, las revistas de impacto y los países que marchan a la cabeza en la investigación, producción y mercado de productos vegetales mínimamente procesados. Se concluyó que los vegetales mínimamente procesados más consumidos en el mundo son la lechuga, la zanahoria, el brócoli, la col y el espárrago. Los principales autores e instituciones dedicados a la investigación en este campo pertenecen a países que presentan un alto desarrollo económico y tecnológico, siendo Estados Unidos el principal rector en la investigación, la producción y comercio de estos productos. Esta investigación dio como producto una biblioteca virtual en el campo de los vegetales mínimamente procesados la cual se encuentra disponible en el sitio http://bives.mes.edu.cu
O trabalho foi desenvolvido com o objetivo de avaliar o efeito da irradiação gamasobre as características físicas e químicas pós-colheita da cenoura da cultivar Nantes. Segundo a Pesquisa de Orçamento Familiar (POF, 1991) realizada na região Sudeste do Brasil, no grupo de raízes e tubérculos, a cenoura é amplamente consumida. Sabe-se, ainda que, a cenoura representa uma das melhores fontes de carotenóides provitamínicos A (alfa e beta caroteno) na dieta. As cenouras foram tratadas com a irradiação ionizante gama, fonte de Césio, nas doses de 0.25, 0.50, 0.75 e 1.0kgy, atendendo a dose máxima permitida pela FDA (1995). Os diferentes tratamentos da cenoura e o grupo-controle foram avaliados através das análises de pH, sólidos solúveis totais (SST), acidez total titulável (ATT), relação SST/ATT, perda de peso, firmeza, cor, carotenóides totais, ácido ascórbico (vitamina C) e voláteis. A análise de variância (tratamento estatístico F de Fisher) dos resultados obtidos mostrou que não houve diferença significativa ao nível de 5% entre os tratamentos e o grupo controle nas diversas análises realizadas, exceto na diferença total de cor, onde houve uma diminuição da mesma com o aumento da dose de irradiação; na acidez total titulável e na relação SST/ATT devido ao decréscimo dos ácidos orgânicos que geralmente ocorrem após a colheita. O processo de irradiação em baixas doses mostra-se promissor na manutenção da qualidade e apresenta-se como uma medida alternativa na redução de perdas pós-colheita.
Salmonella contamination of tomatoes is a recurrent food safety concern.
Irradiation inactivates pathogens on fresh and fresh cut produce.
However, the interaction of time in refrigerated storage and modified
atmosphere packaging (MAP) may influence the response of pathogens to
irradiation. Roma tomatoes were sliced and inoculated with a cocktail of
outbreak strains of Salmonella. The inoculated tomatoes were packaged
under one of four atmospheres: air, 10/90 O2/N2,
5/95 O2/N2 or 100% N2. The packages
were kept in refrigerated storage (10 °C) for various times after
inoculation, to simulate the potential time delay between packaging and
irradiation treatment. Tomatoes were irradiated immediately (0 h), or
after 24 or 48 h in storage. The surviving populations were recovered
and enumerated. Irradiation effectively reduced Salmonella at all times.
Estimated D10 value (the dose necessary for 1 log reduction)
varied significantly among the combinations of time and MAP, ranging
from 0.165-0.335 kGy. Tomatoes packaged in air, irradiated at 0 h,
had a D10 of 0.165 kGy; all other combinations showed
significantly higher D10. Reduced oxygen generally resulted
in higher D10 values, with the highest D10 of
0.335 kGy obtained for 100% N2, 0 h. Time in storage
pre-irradiation tended to increase D10 for air and 5/95
O2/N2, but not for 10/90
O2/N2 or 100% N2. These results suggest
that time required for refrigerated holding of processed Roma tomatoes
or shipment to an off-site irradiation service provider may alter the
efficacy of irradiation if reduced oxygen MAP is used.
This study was carried out to evaluate the shelf life of minimally processed (MP) watercress exposed to gamma radiation with doses of 1.0; 3.0; 4.0 kGy. Packaged irradiated and non-irradiated MP watercress was subject to sensory analysis. A panel consisting of 25-30 non-trained members, aged 20-55 years, was used. Sensory evaluation was carried out on days 0, 2, 5, 7, 9 and 12 after treatment with packages maintained at 7 degrees C. The members of the panel rated each sample for overall liking on a hybrid 10 hedonic scale (0 = extremely dislike; 10 = extremely like). Microbiological analyses were also conducted. Compared to the non-irradiated sample, I kGy irradiated watercress increased its shelf life by one day (16 days). Shelf lives of samples exposed to higher doses were reduced to 9 days (3 kGy) and 6 days (4 kGy) due to changes in appearance. The microbiological quality was good throughout the experiment.
The effects of irradiation on microorganisms and physiological quality of fresh-cut lettuce were evaluated during storage at 4°C. The total bacterial counts on fresh-cut lettuce irradiated with 1.0kGy were reduced by the order of 2.35 Log CFU/g, and the total coliform group were lowered to less than 30 MPN (most probably number)/100g. The polyphenoloxidase activity of fresh-cut lettuce was significantly inhibited by irradiation. In addition, the loss of vitamin C of fresh-cut lettuce irradiated with 1.0kGy was significantly (α=0.05) lower than that of non-irradiated. The best treatment of maintaining quality of fresh-cut lettuce appeared to be 1.0kGy irradiation.
Purpose of the review: Postharvest losses of fruits and vegetables can amount to as much as 40% of the harvested mass of produce. Even before harvest, significant insect damage can occur, resulting in even higher crop losses. In addition, disease-causing pathogens that are present at harvest pose a threat to consumers. Food irradiation technology offers a potential solution to these problems. When used in combination with other technologies, irradiation reinforces the overall efficacy of the treatment through synergistic effects. Furthermore, irradiation treatments can stimulate the biosynthesis of bioactive compounds. This paper focuses on the use of irradiation on fruits and vegetables and the associated effects, and examines the potential for using combined treatments to maintain quality.Main findings: Irradiation is a highly effective treatment that is performed at ambient temperature. It is considered a viable sanitary and phytosanitary treatment for food and agricultural products. Although irradiation is the most extensively studied food processing technology, it is still considered a relatively new technology. It can take a long time for innovative approaches to achieve wide acceptance. Humans fear the unknown and are inclined to resist change. Considerable efforts need to be devoted to public education in this area.Directions for future research: Although a great deal of progress has been made during the last few decades, new and more efficient irradiation technologies and combined treatments still need to be developed, particularly for sensitive fruits and vegetables, in order to ensure their safety while also reducing process energy consumption.
Minimally processed carrots have a short shelf-life because of white blush formation (caused primarily by surface dehydration) and microbiological spoilage (caused mostly by lactic acid bacteria). The use of polymeric packaging films combined with edible coatings might have an additive or synergistic effect to extend the shelf-life of minimally processed carrots because of the formation of a double barrier to gases and water vapour. A 3 × 3 factorial experiment using a polymeric packaging film of three different levels of permeability and a cellulose-based edible coating (Nature Seal®) at different concentrations was conducted on minimally processed carrots to investigate any possible synergistic effect over 12 days of storage at 10 °C. No such effect was found. The polymeric packaging film effectively prevented microbiological growth and spoilage but was unable to control white blush formation. On the other hand, the edible coating partially controlled white blush formation but enhanced microbiological spoilage. The polymeric packaging film functioned primarily as a gas barrier, whereas the edible coating probably functioned as a moisture barrier. White blush formation was found to be the most important shelf-life determinant for minimally processed carrots. Copyright © 2003 Society of Chemical Industry
Introduction Produce Microbiology and Irradiation Treatment Irradiation to Enhance Microbial Safety of Produce Shelf-Life and Quality Changes Conclusion
The primary method to eliminate, or significantly reduce, pathogens on produce is strict adherence to Good Agricultural Practices (GAPs), Good Manufacturing Practices (GMPs), Hazard Analysis Critical Control Points (HACCP), and other relevant strategies that prevent contamination from occurring. This includes the concept of "good management practices" as described in the Guide to Minimize Microbial Food Safety Hazards for Fresh Fruits and Vegetables (FDA 1998). Although the frequency of produce contamination by pathogens is thought to be very small, there are no known mitigation strategies that will completely remove pathogens after contamination has occurred while maintaining produce freshness. A variety of mitigation regimens and sanitizers are available to reduce microbial populations depending upon the type of produce involved. Washing and sanitizing efficiencies depend on several factors, including characteristics of the produce surface, water quality, cleaner/sanitizer used, contact time, and presence and type of scrubbing action. Based on reported data, it is likely that different sanitation mitigation strategies are needed for different produce items.
Introduction Physiology Sensory Quality Phytonutrients Microbiology Treatments to Maintain Quality Conclusions Literature Cited
The preservation of foods, an important manufacturing step that is used to provide food safety, maintain quality, extend shelf-life, and prevent spoilage, has long been called “food processing.” In the context of this book “process” is an operation or treatment, and especially in manufacture, a procedure for forward movement such as cutting, slicing, dicing, washing, etc. (Anon., Webster’s 1987). To “preserve” is the act or process of preserving, by canning, pickling, or similarly preparing food for future use (Anon., Webster’s 1987). Preservation methods then are the “actual” acts of preserving to reduce spoilage. Nicolas Appert in 1810 was probably the first person to explain preservation methods primarily by heating in his treatise “The Art of Preserving Animal and Vegetable Substances.” He originally stated (before the completion of his work) that preserving foods could be reduced to two principal methods, “one in which desiccation is employed and the other in which more or less of a characteristic foreign substance is added to prevent fermentation and putrefaction.” In his book the latter treatment refers to the use of sugar, vinegar, or salt.
Minimally processed refrigerated (MPR) fruits and vegetables have always been an important food group in the diet. However, consumers have recently become more aware of the importance of these products in maintaining health. Consequently, consumers are purchasing and eating more fresh produce and demanding a greater variety of these products in the marketplace. This has led food processors to take advantage of modern technology and transportation to satisfy the consumer’s demand. Despite improved methods of maintaining quality and shelf-life of MPR produce, a limiting factor to optimum quality is the same as before. That component is the role of microorganisms in the spoilage and safety of MPR produce.
Shredded carrots were either chlorinated, rinsed, and spin-dried as in industrial processes, or irradiated (2 kGy), replacing the three steps. Several factors defining the quality of minimally processed vegetables were monitored during storage at 10°. Atmospheres inside micro-porous plastic bags stabilized at 7–15% O2 and 10–15% CO2. Sugar levels in tissues were twice as high in irradiated samples as in chlorinated ones. Irradiation also prevented losses of orange color and carotenes. Growth of aerobic mesophilic and lactic microflora was strongly inhibited by irradiation. Sensory analysis demonstrated preferences for irradiated vegetables. Irradiation, avoiding three potential denaturing steps preserved “ready-to-eat” shredded carrots with better quality than those prepared by conventional industrial processes.
The oxygen effect has been studied in Escherichia coli B/r irradiated with high-intensity pulsed electrons as a function of oxygen concentration. The dose to the cells was delivered in single pulses of time duration 30 nanoseconds. As was observed previously at low oxygen concentrations, survival measured under pulsed conditions for higher concentrations is greatly different from that obtained under relatively low-dose-rate conditions. Typically, the survival curve for cells which are pulse-irradiated follows the oxygenated response to a point dependent on concentration before breaking away to parallel the slope of the survival curve measured under conditions of pure nitrogen. A plot of the "break-point dose" versus oxygen concentration appears linear. The data can be interpreted as further support for a hypothesis based on oxygen depletion within the cell by the first part of the electron pulse previously proposed for Serratia marcescens pulse-irradiated at low oxygen concentrations. The data can also provide a basis for the direct measurement of oxygen diffusion time in cells.
Minimally processed fresh (MPF) fruits and vegetables are good media for growth of microorganisms. They have been involved in outbreaks because of the consumption of products contaminated by pathogens. They are also sensitive to various spoilage microorganisms such as pectinolytic bacteria, saprophytic Gram-negative bacteria, lactic acid bacteria, and yeasts. Contamination of MPF fruits and vegetables occurs at every stage of the food chain, from cultivation to processing. Polluted environments during cultivation or poor hygienic conditions in processing increase the risk of contamination with foodborne pathogens. Although MPF fruits and vegetables may harbor psychrotrophic microorganisms such as fluorescent pseudomonads or Listeria monocytogenes, good control of refrigeration temperature limits growth of spoilage and pathogenic microorganisms. Modified atmospheres are often efficient to maintain or improve visual organoleptic quality of MPF fruits and vegetables, but their effects on microorganisms are inconsistent. Chemical disinfection can partially reduce the initial bacterial contamination; irradiation seems to be more efficient. The applications of legislations and quality assurance systems to control contamination, survival, and growth of foodborne pathogens in MPF fruits and vegetables are discussed.
Effet de l'ionissation sur le maintien de la qualite des legumes de quatrieme gamme
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Essentials of the Microbiology of Foods Radurization and radicidation: fruits and vegetables. Ch. 3 in Preser-vation of Food by Ionizing Radiation The microbiology of minimally processed fresh fruits and vegetables
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Colony count meth-ods. In Compendium of Methods for the Microbiological Examination of Foods Public Health Service and FDA. 1995. Section 3-502.12: Reduced oxygen pack-aging criteria
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Section 179.26: Ionizing radiation for the treatment of food
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FDA. 1995. Section 179.26: Ionizing radiation for the treatment of food. In Code of
Federal Regulations: Food and Drugs, Title 21, p. 389-390. U.S. Gov. Printing Office, Washington, DC.
Radurization and radicidation: fruits and vegetables. Ch. 3 in Preservation of Food by Ionizing Radiation
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Colony count methods
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75-95. APHA, Washington, DC.
Barmore for analytical methods for headspace CO 2 and O 2
- Charles R We
We thank Charles R. Barmore for analytical methods for headspace CO 2 and O 2.
Section 3-502.12: Reduced oxygen packaging criteria
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DC.