Spoilage Level Research Articles

Determinants of fish catch and post-harvest fish spoilage in small-scale marine fisheries in the Bagamoyo district, Tanzania

The fisheries sector of Tanzania is dominated by small-scale fishers who produce up to 95% of the total amount of fish caught in the country. The small-scale fisheries are constrained by inadequate infrastructure, including a lack of capacity for processing and cold storage facilities, poor transportation and fishing tools that increase post-harvest losses. Small-scale fishers lack sufficient capital and skills to invest in modern fishing technologies. Additionally, social-demographic aspects of the fishers, such as education level, gender, age, fishing experience and training influence access to fishing resources and capital, leading to variation in fish catch and post-harvest losses. Thus, this study examined factors that influence fish catch and spoilage in small-scale fisheries in the Bagamoyo District, Tanzania. Forty randomly selected fishers from the Mlingotini fishing village were interviewed. The results show that after spending an average of 11 h per fishing session, the fishers catch an average of 18.5 kg of fish. The amount of fish captured differed with fishing experience, age and sex of the fisher, education level of the fisher, and the time spent selling the captured fish. On average, 10% of the weight of the fish captured per fishing session spoils. The level of spoilage varied according to the fisher's age and sex, education level, fishing experience, length of fishing session, and fishing gear used. Provision of training related to fish processing and handling and improvement of cold storage and transport facilities are recommended to reduce spoilage.

Evaluation of poly(L-lactic acid) (PLLA) rapid indicator film on deterioration degree of Refined, Bleached and Deodorised Malaysian Tenera palm olein oil (RBDPO) during long-term repetitive deep-fat frying

Palm olein oil is widely used as a medium for deep-frying purposes in the domestic and commercial sectors. However, repetitive usage beyond the recommended cycle leads to significant deterioration and spoilage of the oil. Therefore, this research investigated the effect of long-term repetitive deep-fat frying on the physicochemical properties of Refined, Bleached and Deodorised Malaysian Tenera Palm Olein oil (RBDPO) as well as the suitability of poly(L-lactic acid) (PLLA) film as a potential rapid indicator to determine the spoilage level of recycled palm olein oil. The study was carried out using three different RBDPO conditions; RBDPO without potatoes (RBDPO-1), RBDPO with potatoes (RBDPO-2), and RBDPO with Afdhal Oil (AO, an oil additive chemical) and potatoes (RBDPO-3). The deep-frying process was performed for 15 mins at 180 ± 5 °C for 15 cycles. Based on the results, the oil temperature fluctuation during the frying process was insignificant for every cycle ( p > 0.05). After 15 frying cycles, all oil samples demonstrated a considerably altered and deteriorated composition, both physically and chemically. The comparison between the 1st and 15th frying cycles showed a significant difference ( p < 0.05) in the decrease of moisture content and contact angle. Furthermore, the redness colour and viscosity for RBDPO-1, RBDPO-2 and RBDPO-3 increased significantly. The RBDPO-2 recorded the highest value for moisture content, contact angle, colour and viscosity after 15 frying cycles with 30.40 ± 0.2%, 26.01 ± 0.02°, 10.77 ± 0.15 Lovibond, and 133.5 ± 0.2 cP, respectively. However, the density value was insignificant ( p > 0.05) between the 1st and 15th frying cycles for all types of oil. Besides, the peroxides value (PV) was steadily increased within the safety limit of Food Act (1983) (Laws of Malaysia: Act 281), with the aldehyde (C O) functional group was detected in all oil samples throughout the 15 frying cycles. Hence, the high correlation between the contact angle and all parameters except density showed that contact angle analysis using PLLA film was a suitable technique for rapid oil spoilage indicator model.

Double-layer indicator films aided by BP-ANN-enabled freshness detection on packaged meat products

Anthocyanins can be used as a pH-sensitive material to indicate freshness of packaged meat products, which can nevertheless be easily degraded, the pigments should be encapsulated in an appropriate matrix. In this study, raspberry anthocyanins were proposed as a novel freshness indicator and were incorporated into low-acyl gellan to improve its stability. Chitosan was used to form an outer layer of a double-layer indicator film. The results showed that the anthocyanin had response to the change of pH value, the double-layer indicator film had strong mechanical properties, low water vapor permeability and good structural compatibility, and the stability of raspberry anthocyanin was improved. To explore the applicability of the developed film system, pork patties and fish balls were selected as test meat products. Back propagation artificial neural network model was established using color of the films as the input and total volatile nitrogen (TVB-N) content as the output. TVB-N contents of pork patties and fish balls increased to spoilage levels after 6- and 3-day storage at 4 ℃; color of the films changed from pink to brown and finally to dark green as storage proceeded. Neural network model well predicted the freshness of packaged meat products based on color change of the films, with R2 of 0.94–0.98.

An Artificial Intelligence Approach Toward Food Spoilage Detection and Analysis.

Aiming to increase the shelf life of food, researchers are moving toward new methodologies to maintain the quality of food as food grains are susceptible to spoilage due to precipitation, humidity, temperature, and a variety of other influences. As a result, efficient food spoilage tracking schemes are required to sustain food quality levels. We have designed a prototype to track food quality and to manage storage systems at home. Initially, we have employed a Convolutional Neural Network (CNN) model to detect the type of fruit and veggies. Then the proposed system monitors the gas emission level, humidity level, and temperature of fruits and veggies by using sensors and actuators to check the food spoilage level. This would additionally control the environment and avoid food spoilage wherever possible. Additionally, the food spoilage level is informed to the customer by an alert message sent to their registered mobile numbers based on the freshness and condition of the food. The model employed proved to have an accuracy rate of 95%. Finally, the experiment is successful in increasing the shelf life of some categories of food by 2 days.

Multipurpose Fruit Juice Machine for Preventing Fruit Wastage in Nigeria Villages

Fruits are produced in large quantities in developing countries because of the favourable climatic conditions but the level of spoilage is high. It is essential to extract and preserve fruit juice to have a regular supply throughout the year. Therefore, it was necessary to develop a machine that could be used to extract juice from several fruits. Thus, the objective of the research work was to develop a multipurpose small scale fruit juice machine that could be adopted by an average farmer in the rural regions to increase their juice intake. A fruit juice extractor was designed, developed and tested. The machine utilised a serrated auger for crushing the fruits before squeezing out the juice. The performance evaluation showed that the machine has an extraction capacity of 88.4 kg h-1 and 84.5 kg h-1 for pineapple and sweet orange respectively. The efficiencies of the juice extractor for pineapple and sweet orange were 91.13% and 85.96% respectively. The average production cost of the machine was estimated as 390 US dollars.

닭고기 저장기간에 따른 품질 변화와 휘발성 황화합물 발생량 분석

This study aimed to evaluate quality changes and generation of sulfur volatiles of different chicken parts (whole-chicken, breast, and leg), according to the storage period (1, 3, 5, 7, and 9 days). All samples eventually exceeded 6 log CFU/mL of total viable counts (TVC) after storage for 9 days (whole chicken), 7 days (breast), and 5 days (leg). pH of the whole chicken, breast, and leg significantly increased with the storage period. The volatile basic nitrogen (VBN) value of whole chicken was 16.70 mg% on day 9, whereas that of the breast and leg exceeded 20 mg% on day 9. The thiobarbituric acid reactive substance (TBARS) values of the whole chicken and leg exceeded 0.30 mg MDA/kg on the 9th and 7th day, respectively, but the breast had not exceeded 0.30 mg MDA/kg even after 9 days. The amounts of sulfur volatiles from spoiled chicken samples, including hydrogen sulfide (HS), methyl mercaptan (MM), dimethyl disulfide (DMDS) and dimethyl sulfide (DMS), increased during storage. In particular, among these four compounds, DMS increased most markedly. When TVC exceeded 7 log CFU/g, the amount of generated DMS increased rapidly. Thus, the presence of DMS was characteristics of potential spoilage bacteria on chilled chicken; therefore, it could be adopted as a potential indicator to monitor freshness based on whether the number of microorganisms on chicken has reached the level of spoilage.

Development of predictive models evaluating the spoilage-delaying effect of a bioprotective culture on different yeast species in yogurt

Yeast spoilage of fermented dairy products causes challenges for the dairy industry, including economic losses due to wasted product. Food cultures with bioprotective effects are becoming more widely used to help ensure product quality throughout product shelf life. To assist the dairy industry when evaluating product quality throughout shelf life and the effect of bioprotective cultures, we aimed to build stochastic models that provide reliable predictions of yeast spoilage in yogurt with and without bioprotective culture. Growth characterizations of Debaryomyces hansenii, Yarrowia lipolytica, Saccharomyces cerevisiae, and Kluyveromyces marxianus at storage temperatures of 7, 12, and 16°C during a 30-d storage period were conducted in yogurt with and without a bioprotective culture containing Lacticaseibacillus rhamnosus strains. The kinetic growth parameters were calculated using the Buchanan growth model, and these parameters were used as baseline values in Monte Carlo models to translate the yeast growth into spoilage levels. The models were developed using 100,000 simulations and they predicted yeast spoilage levels in yogurt by the 4 yeast types. Each modeled yogurt batch was set to be contaminated with yeast at a concentration drawn from a normal distribution with a mean of 1 log10 cfu/mL and standard deviation of 1 log10 cfu/mL and stored for 30 d at a temperature drawn from a normal distribution with a mean of 6.1°C and a standard deviation of 2.8°C. Considering a spoilage level of 5 log10 cfu/mL, the predicted number of spoiled samples was reduced 3-fold during the first 10 d and by 2-fold at the end of shelf life when a bioprotective culture was added to the yogurt. The models were evaluated by sensitivity analyses, where the main effect factors were maximum yeast population, storage temperature, and yeast strain. The models were validated by comparing the model output to actual observed spoilage data from a European dairy using the bioprotective culture. When the model prediction, based on a mixture of the 4 specific yeast strains, was compared with spoilage data from the European dairy, the observed effect of bioprotective cultures was considerably higher than predicted, potentially influenced by the presence of contaminating strains more sensitive to a bioprotective culture than those characterized here. The developed Monte Carlo models can predict yeast spoilage levels in yogurt at specific production settings and how this may be affected by various parameters and addition of bioprotective cultures.

Storage stability of vacuum packaged turkey meat sausages incorporated with carrot and radish paste during refrigerated storage

The present study was intended to evaluate the shelf life of vacuum packed turkey meat sausages incorporated with raw carrot paste (RCP) and raw radish paste (RRP) each at 10% level under refrigeration (4±1 °C) for a period of 25 days. The sausages were evaluated for physico-chemical, microbiological and organoleptic quality at an interval of 5 days during refrigeration storage. The quality parameters were significantly (P< 0.05) affected due to the incorporation of raw carrot paste (RCP) and raw radish paste (RRP) and also due to refrigeration storage. The results revealed that there was a significant (P< 0.05) increase in the pH, TBARS value and Tyrosine value as storage progressed from 0-25 days. However, the values were well below the threshold level of spoilage. Standard plate counts increased significantly (P< 0.05) as storage period progressed from 0-25 days. Psychrophilic counts were not detected in the control and treated sausages at 0th day, afterwards the psychrophilic counts increased significantly (P< 0.05) as storage period progressed from 5-25 days. Yeast and mould counts were not detected in any of the products throughout the entire storage period. Sensory evaluation revealed a decrease in the sensory scores with the advancement of storage during entire storage period. Based on the results, it can be concluded addition of raw carrot paste (RCP) and raw radish paste (RRP) each at 10% level would not only extends the shelf life by protecting the product longer against oxidative rancidity but also had higher acceptability than control and their use in meat products can enhance the shelf life up to 25 days under refrigerated storage without undesirable changes.

Effect of Storage Conditions on Microbiological Characteristics, Biogenic Amines, and Physicochemical Quality of Low-Salt Fermented Fish

The present study was conducted to evaluate the effects of long-term storage at various temperatures (4, 25, and 35°C) on flavor and microbiological and physicochemical qualities of traditional Chinese low-salt fermented fish (Suanyu). Food spoilage and pathogenic bacteria (coliforms, Pseudomonas, and Salmonella) were inhibited during the 90 days of storage at all temperatures. Lactic acid bacteria, yeast, and total viable bacteria counts of samples stored at 35°C were reduced sharply, whereas other parameters were stable. Compared with refrigerated storage (4°C), higher storage temperatures (25 and 35°C) accelerated moisture migration, lipid oxidation, and proteolytic degradation. Storage time had a greater effect than storage temperature on the increase of volatile compounds in Suanyu. Refrigerated storage was better than higher storage temperatures (25 and 35°C) for maintaining the odor quality of Suanyu during the storage period. Total biogenic amine concentrations in all samples were ≪200 mg/kg. Suanyu can be consumed safely during 90 days of storage based on the levels of spoilage and pathogenic bacteria and concentrations of biogenic amines, but refrigerated storage effectively slows down the microbial and physicochemical changes, resulting in better organoleptic quality. The results of this study will be useful for processors controlling the safety and quality of fermented fish during transport and storage.

Microbiological Stability and Overall Quality of Ready-to-Heat Meals Based on Traditional Recipes of the Basilicata Region

The quality of ready meals is affected by several factors that may impair stability and nutritional value. In this work, we evaluated the overall quality of four traditional meals (Basilicata region) prepared according to the cook&chill method, packaged in air or modified atmosphere packaging (MAP; 70% N2 and 30% CO2), and stored at 4 °C for seven days. The shelf-life was determined by Listeria monocytogenes challenge testing and inactivation by microwave (MW) heating was assessed. The counts at the production day were excellent in three meals out of four, whereas one had high levels of spoilage and pathogens both as soon as the preparation and after seven days. MAP was partially effective only against the growth of the aerobic mesophilic species, whereas sensory analysis revealed that MAP may preserve many of sensory attributes. The average shelf-life of the meals ranged from 11 to 13 days, however, the potential shelf-life was undetectable in one out four meals, as L. monocytogenes growth was inhibited two days after the inoculum. In the inoculated meals, MW heating provided a partial inactivation (25%) of the pathogen. The overall quality of type the meals was partially satisfactory; post-cooking contaminations may affect the microbial load and reduce the palatability over the storage period and, above all, may involve biological hazards which consumers’ habits may not be able to eliminate.

Microbiological and physicochemical parameters for predicting quality of fat and low-fat raw ground beef during refrigerated aerobic storage.

The aim of the current study was to identify quality indicators of fat (14.50±0.75%) and low-fat (4.79±0.63%) raw ground beef by monitoring changes in physicochemical and microbiological parameters during aerobic refrigerated storage, such as water-holding capacity, pH, thiols, carbonyl compounds, thiobarbituric acid reactive substances (TBARS), metmyoglobin, deoxymyoglobin, oxymyoglobin color indices, pseudomonads, Brochothrix thermosphacta, and total viable counts. Meat packaged in air-permeable polyethylene plastic film was stored under controlled isothermal conditions (0, 5, 10, and 15 °C). A population level of pseudomonads equal to 7.0±0.5 log10 colony forming units (CFU)/g was considered as the potential spoilage level. Using principal component analysis, samples were distinguished on the basis of their microbial load. A significant positive correlation between microbial population and carbonyls, metmyoglobin, TBARS, water-holding capacity, and a negative correlation with thiols and color parameters (L* , chroma) were observed. Two different approaches were followed to estimate the quality status of samples: (i) the partial least square (PLS) regression with R2 of 0.93 and root mean square error prediction of 0.44 for pseudomonads, using the above physicochemical characteristics as the dominant input variables, which allowed prediction of the microbiological status of ground beef regardless of time-temperature storage profile and fat content, and (ii) a square-root-type model (adjusted R2 of 0.952) that satisfactorily predicted the growth of spoilage pseudomonads under isothermal and dynamic conditions, regardless of the above physicochemical changes. The above results suggest that depending on the available input data, the two modeling approaches can accurately (and complementarily) assess quality of aerobically stored ground beef. PRACTICAL APPLICATION: Changes in appearance and quality of fat and low-fat raw ground beef are associated with physicochemical alteration and/or microbial growth. The study provides two different modeling approaches that can be integrated in an intelligent interface of the refrigerator having specific colorimetric and/or temperature sensors, to evaluate in a convenience way the quality of stored meat thus reducing domestic waste: the partial least square model was based on physicochemical parameters (particularly chroma, metmyoglobin, and thiobarbituric acid reactive substances), while the square root model was based on the time-temperature conditions during storage.

Storage stability of turkey meat sausage incorporated with carrot and radish under refrigerated storage

The present study was aimed to evaluate the antioxidant and antimicrobial efficacy of raw carrot paste (RCP) and raw radish paste (RRP)each at 10 % level on aerobic packaged turkey meat sausages under refrigeration (4±1°C) for a period of 25 days. The stored sausages were evaluated for physico-chemical, microbiological and sensory characteristics at an interval of 5 days. The pH of the turkey meat sausages increased significantly (P<0.05) in both control and treated sausages under aerobic packaging. The results revealed that there was significant (P<0.05) increase in the physico-chemical parameters viz., Tyrosine value and TBARS value, as storage progressed from 0-25 days. However, the values were well below the threshold level of spoilage at the end of storage period. Standard plate counts, increased significantly (P<0.05) as storage period progressed from 0-25 days. Psychrophilic counts were not detected in the control and treated sausages at 0th day, afterwards the psychrophilic counts increased significantly (P<0.05) as storage period progressed from 5-25 days. Yeast and mold counts were not detected in any of the products throughout the entire storage period. A reduction in the sensory scores of turkey meat sausages were found as the advancement of storage. Based upon the results, it can be concluded that addition of raw carrot paste (RCP) and raw radish paste (RRP) each at 10 % level would not only extends the shelf life by protecting the product longer against oxidative rancidity but also had higher acceptability than control.

Supply-Side Analysis of the Market for Tomato in Bauchi State, Nigeria

The benefits of tomato to human health among the vegetable family cannot be overemphasized. Tomatoes are grown for home consumption in the backyard of many households across sub-Saharan Africa. They are important sources of vitamins as well as essential cash crop for both smallholders and medium-scale commercial farmers. A number of studies have shown that tomato is grown in commercial quantity anywhere agronomic conditions allow. In Nigeria and many countries of the world, tomato has become one of the most important crops in agriculture for smallholder farmers both for processing and fresh market. This paper analyses the supply side of the market for tomato in Bauchi State, Nigeria. The data employed were purposively obtained from farmers, wholesalers and retailers from agricultural areas in 7 Local Government Areas of Bauchi State. These include Bauchi, Alkaleri, Toro, Kari, Shira, Darazo, and Ganjuwa. Analysis is mainly predicated on the weighted least squares regression in order to address the problems that may arise from having heteroskedastic errors in the models. The findings show that farm characteristics majorly affect supply of tomatoes while handling costs and cooperative membership are mainly responsible for loss of tomatoes across the marketing chain. Also, cooperative membership does not play a significant role in improving the situations of neither the farmers nor the middlemen in terms of increased profitability and supply. In addition, socioeconomic and farm characteristics are found to be key factors affecting tomatoes’ profitability. Therefore, farmers should be encouraged to embrace a competitive market setting in order to achieve a free flow market interaction in the determination of price. A favourable farm-land ownership and acquisition policy should be made by government in order to increase output of tomatoes and consequently, higher profitability. This is most likely to have a positive influence on employment generation as more rural populace would be engaged in the production of farm products. Besides, infrastructural development, specifically in the area of transportations needs to be enhanced by the government in order to ease movement of agricultural produce from the point of harvest to their final destinations. Attention should also be given to government investment in storage facilities to minimize the spoilage level of farm produce in Nigeria. Farm cooperatives should be reformed so as to promote profitability of the agricultural firms.

Pemanfaatan Lengkuas (Alpinia galanga L. Swartz) Untuk Mengawetkan Ikan Pindang Tongkol (Euthynnus pelamis L.)

The objective of this research was to prove that galangale rhizome (Alpinia galanga L. Swartz) can be used to preserved “pindang” tuna fish (Euthynnus pelamis L.). The fish were cooked by galangale rhizome solution (the concentration were 0, 50, 100, 150, 200 mg/l b/v) for15 minutes. Then, the fish were stored in box, three fishes /box, and stored at room temperature for 6 days. Every day, The quality of fish were measured as colour, rubberness, taste, odor, total of bacteria and fungi. The result showed that there were decreased of the fish quality, spoilaged, and many fungi and bacteri growth after two days, and the level of spoilage of fish was influenced the increasing of galangale rhizome concentration. It concluded that the galangale rhizome can not use as “pindang” tuna fish preservative.

Range-extended wireless food spoilage monitoring with a high energy efficient battery-free sensor tag

In this study, we developed a smart sensor tag without a battery for monitoring spoilage in packaged foods. To give our smart sensor tag a compact structure for inserting into food packaging, we designed a double PCB structure with two 6-turn rectangular antennas. The first PCB includes several low power sensors for monitoring food spoilage, a transceiver IC for communication with a reader, a microcontroller for the smart sensor tag operations, and a 6-turn rectangular antenna at the edge of the PCB. The second relay PCB contains another 6-turn rectangular antenna (that is the same size as the first antenna) and is parallel to the first board. This second PCB is designed as a relay resonator to improve the RF energy harvesting efficiency from the reader side. The antenna on the first board transmits data to the reader and simultaneously operates as a receiver resonator for RF energy harvesting. To evaluate the food spoilage, the proposed smart sensor tag was designed to have several low power sensors that monitor factors including humidity, temperature, total volatile organic compounds, and equivalent carbon dioxide. Validation results showed that the proposed smart sensor tag with the sensor module is able to collect the sensing data on food spoilage without a battery, at a maximum distance of 50 cm from a reader. The collected sensing data were analyzed with a personal computer to evaluate spoilage level in food packages.

Online Feature Selection for Robust Classification of the Microbiological Quality of Traditional Vanilla Cream by Means of Multispectral Imaging.

The performance of an Unsupervised Online feature Selection (UOS) algorithm was investigated for the selection of training features of multispectral images acquired from a dairy product (vanilla cream) stored under isothermal conditions. The selected features were further used as input in a support vector machine (SVM) model with linear kernel for the determination of the microbiological quality of vanilla cream. Model training (n = 65) was based on two batches of cream samples provided directly by the manufacturer and stored at different isothermal conditions (4, 8, 12, and 15 °C), whereas model testing (n = 132) and validation (n = 48) were based on real life conditions by analyzing samples from different retail outlets as well as expired samples from the market. Qualitative analysis was performed for the discrimination of cream samples in two microbiological quality classes based on the values of total viable counts [TVC ≤ 2.0 log CFU/g (fresh samples) and TVC ≥ 6.0 log CFU/g (spoiled samples)]. Results exhibited good performance with an overall accuracy of classification for the two classes of 91.7% for model validation. Further on, the model was extended to include the samples in the TVC range 2–6 log CFU/g, using 1 log step to define the microbiological quality of classes in order to assess the potential of the model to estimate increasing microbial populations. Results demonstrated that high rates of correct classification could be obtained in the range of 2–5 log CFU/g, whereas the percentage of erroneous classification increased in the TVC class (5,6) that was close to the spoilage level of the product. Overall, the results of this study demonstrated that the UOS algorithm in tandem with spectral data acquired from multispectral imaging could be a promising method for real-time assessment of the microbiological quality of vanilla cream samples.

Domestic refrigerator temperatures in Spain: Assessment of its impact on the safety and shelf-life of cooked meat products.

Temperature is one of the main factors governing the growth of microorganisms. The aim of the present study was to provide temperature conditions representative of the food products stored in domestic refrigerators and to assess the impact of the temperature (fluctuation) on the shelf-life of refrigerated cooked meat products, from the safety and the spoilage point of view. The analysis of the time-temperature profiles recorded from 160 domestic refrigerators of households from small (28%) and large (72%) municipalities in Catalonia (Spain) showed that the 24 h-mean temperature could be described by a normal distribution (mean = 5.4 °C, standard deviation = 2.3 °C) with a mean value within the upper limit of the appropriate storage temperature of refrigerated products (i.e. ≤6 °C). The impact of door openings or day and night was not significant. Temperature distribution showed differences depending on the season, being higher in the cold season than in the warm one. Noteworthy, refrigerators of elderly (≥ 65 years old) households showed a higher percentage of time at temperatures >8 °C in comparison with those of the general population. Overall, the 75th percentile of the distribution of the 24 h-mean temperature values was 6.7 °C. This study can be used as a scientific evidence of the consumer storage stage when food business operators or laboratories conduct shelf-life studies. According to the simulation of the growth of Listeria monocytogenes and lactic acid bacteria in cooked meat products, risk scenarios were identified in which the critical level of the pathogen could be reached before lactic acid bacteria achieved the spoilage level. The fluctuation of the refrigerator temperature ranged from 0.5 up to 12.2 °C within the 24 h-profile. The assessment of the safety of cooked meat products stored at constant temperature or under different time-temperature profiles showed that both the mean and the fluctuation of the profile had an impact on the shelf-life, which was higher at low temperatures. The improvement of the household refrigerated storage would be an effective way to increase food safety of refrigerated ready-to-eat food.

A gas Fourier transform infrared spectroscopy methodology for the rapid and accurate discrimination of chicken spoilage through volatiles analysis

AbstractThe discrimination of chicken spoilage is extremely important in order to guarantee the quality and safety of chicken before consumption, and requires an efficient and reliable method. We aimed to find a rapid and accurate method to discriminate the level of spoilage of chicken, and have developed a gas Fourier transform infrared spectroscopy (G‐FTIR) methodology based on analysing volatiles from chicken samples. In this method, the volatiles of chicken samples were first measured by the G‐FTIR spectrometer. After that, a chemometrics method combining principal component analysis (PCA) with support vector machine (SVM) was developed to encode the G‐FTIR spectra. With the combination of G‐FTIR spectra and the chemometrics method, a relationship between the spoilage levels of chicken and the G‐FTIR spectra of volatiles was established. As a result, the spoilage levels of chicken samples were accurately distinguished with a prediction accuracy of 100%, for samples stored at both normal (20 °C) and cold (4 °C) temperatures. The results obtained were correlated with the routine total volatile basis nitrogen (TVB‐N) method for validation. In addition, The G‐FTIR detection process for each sample could be performed within 3 min, requiring no chemical reagents. The G‐FTIR methodology performed well for the rapid discrimination of chicken spoilage, which could also be extended to the detection of other spoiled foods.

Wine quality rapid detection using a compact electronic nose system: Application focused on spoilage thresholds by acetic acid

It is crucial for the wine industry to have methods like electronic nose systems (E-Noses) for real-time monitoring thresholds of acetic acid in wines, preventing its spoilage or determining its quality. In this paper, we prove that the portable and compact self-developed E-Nose, based on thin film semiconductor (SnO2) sensors and trained with an approach that uses deep Multilayer Perceptron (MLP) neural network, can perform early detection of wine spoilage thresholds in routine tasks of wine quality control. To obtain rapid and online detection, we propose a method of rising-window focused on raw data processing to find an early portion of the sensor signals with the best recognition performance. Our approach was compared with the conventional approach employed in E-Noses for gas recognition that involves feature extraction and selection techniques for preprocessing data, succeeded by a Support Vector Machine (SVM) classifier. The results evidence that is possible to classify three wine spoilage levels in 2.7 s after the gas injection point, implying in a methodology 63 times faster than the results obtained with the conventional approach in our experimental setup.

Aroma Profile Characterization of Mahi-Mahi and Tuna for Determining Spoilage Using Purge and Trap Gas Chromatography-Mass Spectrometry.

Alcohols, aldehydes, ketones, amines, and sulfur compounds are essential aroma compounds related to fish flavor and spoilage. Gas chromatography-mass spectrometry (GC-MS) is an instrument that is widely used to identify and quantify volatile and semi-volatile compounds in fish products. In this research, a simple and accurate GC-MS method was developed to determine the aroma profile of mahi-mahi and tuna for chemical indicators of spoilage. In the developed GC-MS method, trichloroacetic acid (TCA) solution was used to extract analytes from homogenized fish samples. The purge and trap system was used for sample introduction, and the GC-MS with an RTX-Volatile Amine column was able to separate compounds without a derivatization procedure. The created purge and trap gas chromatography-mass spectrometry (PT-GC-MS) method could identify and quantify twenty aroma compounds in mahi-mahi (Coryphaena hippurus) and 16 volatile compounds in yellowfin tuna (Thunnus albacares) associated with fish spoilage. The amines (dimethylamine, trimethylamine, isobutylamine, 3-methylbutylamine, and 2-methylbutanamine), alcohols (2-ethylhexanol, 1-penten-3-ol and isoamyl alcohol, ethanol), aldehydes (2-methylbutanal, 3-methylbutanal, benzaldehyde), ketones (acetone, 2,3-butanedione, 2-butanone, acetoin), and dimethyl disulfide strongly statistically correlated with poorer quality tuna and mahi-mahi and were considered as the key spoilage indicators. PRACTICAL APPLICATION: A simplified and rapid purge and trap gas chromatography-mass spectrometry (PT-GC-MS) method developed in this research was able to identify and quantify important spoilage compounds in mahi-mahi and yellowfin tuna. This method is an efficient analytical method for determining volatile profiles of fish samples for industry analytical labs or the government. The identified analytical quality markers can be used to monitor the spoilage level of tuna and mahi-mahi.