Blast Chilling Research Articles

Thermoeconomic model for diagnostic techniques to evaluated vapor compression refrigeration system performance

In recent years, it has been possible to observe a significant expansion of the refrigeration and air conditioning industry. Considering that food refrigeration systems (blast chilling or freezing, cold storage, retail display, etc.) and air conditioners are large energy consumers, this work presents a methodology for evaluating the performance and behaviour of these systems using the thermoeconomic diagnosis concept. The thermoeconomic model used allowed the definition of the condenser and expansion device products, which is not trivial for these components. With that, the thermoeconomic diagnosis was used to evaluate the degradation of refrigeration system components, together with the influence of individual component degradations on efficiency, cooling capacity, operating parameters, and power consumption of the whole system. Through this analysis, a prognosis of system behaviour was obtained, which can be used for maintenance scheduling, as well as for the comprehensive energetic and exergetic analysis of a refrigeration system and each of its components.

Effects of cooking methods on the quality and safety of crayfish ( Astacus leptodactylus Eschscholtz, 1823) during chilled storage

The aim of this study was to investigate the effects of three different cooking methods on the quality and shelf life of crayfish during chilled storage. The changes in the physical, chemical, microbiological and sensory qualities of three different cooked crayfish (boiled: BC: sous vide cooked: SVC and microwaved: MC) were monitored during chilled storage (2±0.7°C). Crayfish were cooked by three cooking methods were cooled by blast chiller. After cooking process, the lowest cooking loss was the SVC group as 1.25 g. The yield percentage was observed for cooked crayfish different cooking methods (sous vide, microwaved, and boiling) was 97.29, 96.27, and 94.40% respectively. Results demonstrated that the microbial and chemical safety of all cooked crayfish were not overall satisfactory for human consumption on the 28 days. However, after 21 days of storage, only the SVC and BC groups, except MC, had acceptable sensory scores from the cooked crayfish.

A Preliminary Color Study of Different Basil-Based Semi-Finished Products during Their Storage.

Basil-based semi-finished products, which are mainly used as an intermediate to produce the typical pesto sauce, are prepared and exported all over the world. Color is a fundamental organoleptic requirement for the acceptability of these semi-finished products by the manufacturers of the pesto sauce. Some alternative formulations, which adjust the typical industrial recipe by both changing the preservative agent (ascorbic acid, citric acid, or a mixture of both) and introducing a preliminary thermic treatment (blast chilling), were evaluated. In this work, a fast and non-destructive spectrophotometric analysis, to monitor the color variations in these food products during their shelf-life, was proposed. The raw diffuse reflectance spectra (380–900 nm) obtained by a UV–visible spectrophotometer, endowed with an integrating sphere, together with the CIELab parameters (L*, a*, b*) automatically obtained from these, were considered, and elaborated using multivariate statistical analysis (principal component analysis). From this preliminary study, blast chilling, together with the use of ascorbic acid, proved to be the best solution to better preserve the color of these products during their shelf-life.

Salmonella enterica e enterobactérias em carcaças suínas processadas em diferentes dias de abate

Abstract The objective of this work was to evaluate the contamination by Salmonella sp. and enterobacteria in pig carcasses from the first and last batches slaughtered in a same week, at different stages of the slaughtering line. Samples were collected from the first and last batches slaughtered on Monday and Friday of each week, respectively, during five weeks, totaling ten batches. From each batch, ten carcasses were collected in eight stages of the slaughter line: bleeding, scalding, singeing/evisceration, inspection, spinal cord removal, final washing, blast chilling, and after cooling. A total of 800 samples were analyzed for Salmonella sp. and enterobacteria quantification. The last batch of the week showed twice the chances of the pig carcasses being contaminated with Salmonella sp. and, consequently, a greater amount of enterobacteria (1.00 log10 CFU per square centimeter) than the first batch (0.88 log10 CFC per square centimeter). A higher count of enterobacteria was also observed in the stages of bleeding (2.37 log10 CFU per square centimeter) and scalding (2.36 log10 CFU per square centimeter). The last batches slaughtered in the week show a greater contamination than the first ones, and there is a greater contamination of carcasses by Salmonella sp. and enterobacteria in the initial stages of pig slaughter, i.e., at bleeding and scalding.

Effects of different stabilization techniques on the shelf life of cold brew coffee: Chemical composition, flavor profile and microbiological analysis

Cold brew coffee is a beverage prepared at low temperatures and over long brewing times resulting in particular physicochemical and sensory characteristics. This type of coffee is usually consumed immediately after preparation or after short storage in refrigerated conditions. However, in recent years many commercial coffee vendors started investing in ready-to-drink cold brew coffees packaged for extended storage. These products present the potential problem of microbial and sensorial alteration. In this study we evaluated five different stabilization techniques with the aim to extend the shelf life of the cold brew coffee while preserving its peculiar organoleptic properties, e.g. HPP (High Pressure Processing), microfiltration, UV irradiation, pasteurization and blast chilling process. The effects were investigated over four months, evaluating the caffeine and the chlorogenic acids contents by HPLC-DAD analysis and carrying out anevaluation of selected volatile compounds by HS-SPME-GC-MS. After four months of storage, the samples treated with pasteurization and HPP maintained a stable content of caffeine and chlorogenic acids, guaranteeing also the microbiological safety of the beverage. At the same shelf-time, the pasteurized samples showed an unaltered flavor profile, while a decrease of about 25% of the total content of volatile compounds was registered for the HPP sample.

Discrimination between Fresh and Frozen-Thawed Fish Involved in Food Safety and Fraud Protection.

This study aims to discriminate fresh fish from frozen/thawed by identification of the key metabolites that are altered during the freezing/thawing processing. Atlantic salmon (Salmo salar) and bullet tuna (Auxis rochei) were selected as they are representative of broad consumption, and susceptible to pathogen contamination. Atlantic salmon samples were subjected to the following regimes: −20 °C (24h) and −35 °C (15 h) freezing, then thawed respectively in the blast chiller and in the cold room and analyzed immediately or after 10 days; (2) bullet tuna samples were frozen at −18 °C and thawed after 15, 30 and 90 days. High resolution mass spectrometry based on untargeted metabolomic analyses and statistical data treatment confirmed significant variations in the quantity of certain metabolites: the amount of l-phenylalanine in salmon increased immediately after thawing while that of anserine decreased. The concentration of l-arginine and its metabolites was altered at the 10th day after thawing rendering them promising markers of salmon freezing/thawing. As regards bullet tuna, compounds resulting from lipid degradation (l-α-Glyceryl-phosphoryl-choline and N-methyl-ethanolamine phosphate) increased notably during the storage period. This approach could be used to reveal common fraudulent incidents such as deliberate replacement of fresh fish with frozen/thawed, with food safety risks as the primary implication.

Disaggregation models for the thermoeconomic diagnosis of a vapor compression refrigeration system

The demand for chilled or frozen pre-cooked food and also for conditioned air has increased significantly in the last years. It is also well known that food refrigeration systems (blast chilling or freezing, cold storage, etc.) and air conditioners are important energy consumers in the tertiary sector. Thus, proper diagnosis techniques are important to avoid excessive energy consumption and to assure that the cooling demands will be met. In order to predict the performance of these systems under off-design conditions, mathematical models of refrigeration and air conditioning systems are presented. Besides that, four malfunctions are simulated and the equilibrium condition for each one of them is calculated. Two thermoeconomic methodologies are used to evaluate the fuel impact of each degradation. It was revealed that different values of degradations and dysfunctions were calculated even though the same fuel impact was obtained. One of the productive structures assessed presented more suitable results for the diagnosis of anomalies due to its use of fewer fictitious flows, which are known to incorrectly influence in the magnitude of exergy flows leading to improper results. Further studies regarding the structure of the malfunctions (intrinsic and induced components) are needed for more accurate diagnosis in refrigeration systems.

In-flight Catering Service and Food Safety: Implementation of Hazard Analysis and Critical Control Point System in PT Aerofood ACS Surabaya

Hazard Analysis Critical Control Point (HACCP) is a system of quality assurance and food safety in preventing the emergence of problems ranging from materials, processes, and products. HACCP is a form of risk management system that is developed to ensure food safety with a preventive approach. This system is adopted to provide food safety assurance in food production process for consumers. The in-flight catering company service observed in this study is PT. Aerofood ACS Surabaya. The implementation of HACCP system in every production process has been applied by this company. However, there is still limited study to explore the implementation of the system in the company and identify any potential impediment of the system. This research is descriptive with observation method on production process of chicken oyster sauce menu. The control points used in the process of chicken oyster sauce production is by controlling the temperature upon receiving raw materials, storage system, cooking process, blast chilling, until portioning. One out of the ten of HACCP implementation stages, monitoring activity was found has not met SNI 01-4852-1998 requirement standard. Monitoring process was not implemented while checking the core temperature of the food during the cooking process. Nine other of HACCP implementations stages including of HACCP team formation, product description, drafting flow chart, hazard identification, critical conrol point determination, critical boundary determination, correction action, verification, and documentation were already in accordance with SNI requirement standard.

The Effect of Rapid Chilling of Pork Carcasses during the Early Postmortem Period on Fresh Pork Quality

The objective was to investigate the effects of blast chilling on pork quality in cuts from the Longissimus thoracic et lumborum (LM), Psoas major (PM), Semimembranosus (SM; both superficial [SMS] and deep [SMD] portions) and the Triceps brachii (TB). Forty carcasses (10 carcasses per replication) were split and sides were assigned to either blast chill (BC, –32°C for 90 min, followed by spray chill at 2°C for 22.5 h) or conventional chill (CC, spray chilled at 2°C for 24 h) regimens. The LM from BC sides had lower (P < 0.05) temperature at 2 h postmortem (CC 21.8°C, BC 9.7°C), 4 h (CC 13.3°C, 3.8°C BC), 22 h (CC 4.2°C, BC 1.4°C), and 30 h (CC 0.4°C, BC –0.2°C). The LM pH in BC sides was higher at 4 h (CC 6.09, BC 6.34), 22 h (CC 5.81, BC 5.89), and 30 h (CC 5.68, BC 5.74) postmortem. The BC resulted in higher (P < 0.05) 30 h postmortem pH in the SM compared to the CC regime (CC 5.68, BC 5.74). The BC sides had increased (P < 0.05) purge in the PM (CC 0.48%, BC 0.74%) and increased (P < 0.05) cook loss in chops from the LM (CC 22.37%, BC 24.24%). The PM from BC sides were more juicy (CC 7.50, BC 8.30), less chewy (CC 2.80, BC 2.10), and more tender (CC 7.90, BC 8.60). Chops from the LM of BC sides had greater Warner-Bratzler shear force (CC 2.00, BC 2.30). Color was affected in the SM with BC sides showing darker color score (CC 3.00, BC 3.20) and redder Hunter a value (CC 16.35, BC 16.02). Chilling treatment did not affect sarcomere length in the LM. Treatment did not affect postmortem proteolysis in any cut. The response to chilling regimen is different across different muscles which may be caused by location, rate of chilling, and fiber type.

Failure analysis of a plate heat exchanger used in a blast chiller

Abstract A stainless steel plate heat exchanger (PHE) was received to investigate the cause of its perforation in service leading to mixing of the fluids (water and refrigerant) circulating in the system. The heat exchanger was employed in a blast chiller using seawater subjected to a reverse osmosis process followed by salinization and sanitizing treatments. This study includes the analysis of water samples in different points of the system, a metallurgical characterization of the material of the plates, a study of the composition of corrosion products and an evaluation of the electrochemical behaviour of the material in the water samples extracted from the system. The study revealed that the material of the plates was perforated by a corrosion process due to the high level of chlorides present in the water employed in the blast chiller. Moreover, the localized attack of the stainless steel plates is enhanced by the peculiar geometry of the heat exchanger that leads to crevice corrosion in the region of the joint between overlapping plates. The results obtained in this work indicate that the failure is associated to the water treatment process performed upstream of the heat exchanger.

National survey of Salmonella prevalence in lymph nodes of sows and market hogs.

Livestock are known to harbor Salmonella in their gastrointestinal (GI) tract and lymphatic tissues. Pathogens may be transferred from the GI tract to external carcass surfaces during normal harvest procedures but can be mitigated by antimicrobial carcass interventions. Lymph nodes (LNs) are typically encased in fat and are protected from antimicrobial carcass surface treatments, thus serving as a possible root cause of foodborne illnesses attributed to Salmonella in meat products. Members of the pork industry are committed to food safety and want to better understand Salmonella as a potential contaminant in pork products. To establish a baseline of Salmonella prevalence in porcine LNs across the United States, 21 commercial pork harvest facilities, representing northern (n = 12) or southern (n = 9) geographical regions, participated in this study. As processing volumes allowed, 25 carcasses were selected from each establishment. From each carcass, left and right superficial inguinal LNs (n =1,014 LNs) were removed and pooled to yield one sample per animal or n = 507 total LN samples. Salmonella prevalence rates differed (P < 0.05) between hog types in both regions. Specifically, 6.4% of market hog and 37.0% of sow samples were Salmonella positive in the northern region. This was reversed in the southern region as 13.0% of market hog and 4.8% of sow samples were Salmonella positive. There also was a difference (P < 0.05) in prevalence rates between northern and southern regions for sows, but not market hogs (P > 0.05). Type of chilling method (conventional, blast, or other) used at each market hog facility (n = 12) was documented. In the northern region, prevalence rates of Salmonella across chilling types were as follows: 20.0%, 2.7%, and 1.3% positive samples for conventional, other, and blast chill methods, respectively. In the southern region, 20.0% of samples were positive for conventional, 0.0% for blast, and 12.0% for other chilling methods. In both regions, samples from conventionally chilled carcasses returned more (P < 0.05) positive results than any other chill method. Overall, the higher rate of Salmonella prevalence in northern sows warrants further investigation, and members of the pork industry would benefit from the identification of possible methods to address the presence of Salmonella in porcine LNs.

PENERAPAN HACCP DALAM PROSES PRODUKSI MENU DAGING RENDANG DI INFLIGHT CATERING

HACCP is one of the food safety systems which is done by analyzing materials, processes, and food products. HACCP analysis can be used as an effort to control the quality of the fi nal product in order to meet the requirements of healthy, safe and halal food products. PT X is a catering company for aircraft service users (infl ight catering). This company has implemented HACCP in every food production. This is a descriptive research by observing the process of rendang meat production. The application of HACCP in PT. X is done by controlling temperature and time during production process to prevent microbes growth. From ten application of HACCP according to SNI No. 01-4852-1998 about HACCP there is a point that has not been accordance with SNI monitoring. Monitoring activities are not routinely performed on blast chilling and dishing process. Pieces of coconut milk’s pack fall in to the pan when cooking process because the cutting of coconut milk pack is done on the cooking pan. Other HACCP principles like HACCP team determination, product description, fl ow chart reaction, hazard identifi cation, critical point determination, critical boundary determination of each CCP, corrective action, microbiological verifi cation, and documentation are well implemented.

Salmonella Prevalence in Lymph Nodes of Sows and Market Hogs in the United States

ObjectivesAntimicrobial interventions are applied to carcass surfaces to mitigate pathogens transferred during harvest. While highly effective, carcass surface interventions are unable to reduce pathogens located within fat-encased lymph nodes (LNs). For this reason, LNs have been identified as a potential cause of Salmonella in beef and pork products. The objectives of this study were to (1) establish a baseline for Salmonella prevalence in LNs of sows and market hogs in the United States, and (2) to determine the impact of carcass chilling methods on Salmonella prevalence in surveyed LNs.Materials and MethodsA total of 21 commercial pork harvest facilities were categorized by region and hog type (n = 8 northern market hog, n = 4 northern sow, n = 4 southern market hog, and n = 5 southern sow). As processing volumes allowed, 25 carcasses were selected from each establishment. From each carcass, left and right superficial inguinal LNs were removed, pooled (n = 507 total LN samples), and subjected to Salmonella prevalence determination. Additionally, type of carcass chilling method (conventional, blast chill, or other) used at each facility was recorded.ResultsSalmonella prevalence rates differed (P < 0.05) between hog types in both regions. Specifically, 6.4% of market hog and 37.0% of sow LN samples were found to be Salmonella-positive in the northern region; in the southern region, 13.0% of market hog and 4.8% of sow samples were Salmonella-positive. There was a difference (P < 0.05) in prevalence rates between regions (northern and southern) for sows, but not market hogs (P > 0.05). In the northern region, prevalence rates of Salmonella across chilling types were as follows: 20.0, 2.7, and 1.3% positive for conventional, other, and blast chill methods, respectively. Additionally, in the southern region, there were 20.0% positive samples for conventional, 0.0% for blast chill, and 12.0% for other chill methods. In both regions, samples from conventionally chilled carcasses returned more (P < 0.017) positive results than any other chill method.ConclusionThe higher rate of Salmonella prevalence in northern sows warrants further investigation. Members of the pork industry would benefit from the identification of subsequent research needs or possible process improvements to address the presence of Salmonella in porcine LNs.

Enumeration of Escherichia coli in swab samples from pre- and post-chilled pork and lamb carcasses using 3M™ Petrifilm™ Select E. coli and Simplate® Coliforms/E. coli

The aim of the study was to compare two analytical methods; 3M Petrifilm™ Select E. coli and SimPlate® Coliforms &E. coli, for detection and enumeration of E. coli using swab samples from naturally contaminated pork and lamb carcasses that were collected before and after chilling. Blast chilling was used for pork carcasses. Swab samples (n=180) were collected from 60 warm and 60 chilled pork carcasses, and 30 warm and 30 chilled lamb carcasses, and analysed in parallel. The concordance correlation coefficient between Petrifilm and SimPlate was 0.89 for pork and 0.81 for lamb carcasses. However, the correlation was higher for warm carcasses (0.90) than chilled carcasses (0.72). For chilled lamb carcasses, the correlation was only 0.50, and SimPlate gave slightly higher results than Petrifilm (P=0.09). Slower chilling gave slightly lesser agreement between methods than for blast chilling, however, both Petrifilm and SimPlate methodologies are suitable and recommended for use in small laboratories in abattoirs.

Investigation on temperature fields in industrial chilling of pork legs for PDO Parma ham production and coupled temperature/microbial growth simulation.

In the present work, temperature distribution within an industrial blast chiller with pork leg for Protected Designation of Origin Parma ham production was studied and the slowest cooling zone and the fastest cooling zone were recognized. Moreover, apparent heat transfer coefficients in both positions were calculated and resulted equal to 27.1 and 15.6Wm-2°C-1, respectively. A finite element method model by distinguishing the three main components (skin, lean meat and bone) of the leg for the unsteady heat transfer during cooling was developed and validated against industrial chiller data. Good agreement between experimental and simulated data was obtained with RMSE value for thermal centre equal to 0.81°C. Furthermore, in order to introduce CCP limit in the HACCP plan, a microbial growth model of the most important pathogens in meat was developed starting from the heat transfer model results. Temperature as well as pathogen growth were estimated in the case of different plant breakdowns. Defined CCP limit was represented by reaching 11 °C at 5 mm of depth within 2 h from the beginning of the cooling process, moreover a different cooling program was simulated and established as the alternative one.

Effects of pork differentiation strategies in Canada on pig performance and carcass characteristics

Performance and quality traits were measured in carcasses from combinations of genotype, diet supplement, slaughter weight, and carcass chilling regime. Iberian-crossed pigs had lower live animal performance than Duroc and Lacombe. From 70 to 115 kg, Lacombe pigs grew slightly faster than Duroc. Duroc carcasses had a higher lean percentage, heavier ham and picnic primals, and lighter loins and bellies, compared with Lacombe and Iberian. Heavier carcasses had lower lean yield, except those from Iberian-crossed pigs, and bigger bellies. Meat from Duroc-crossed pigs was lighter in colour and higher in marbling, with intermediate values for fat hardness. Iberian carcasses displayed dark meat with intermediate marbling and the hardest fat. Meat from Lacombe pigs was the leanest although, like in all three breeds, marbling scores were higher in heavier carcasses. Generally, supplementing with canola and flax decreased and blast chilling increased fat hardness values. Dietary canola also seemed to affect meat colour traits, but these effects were not consistent among breeds and slaughter weights. The commercial combination of Duroc breed, control diet, and 115-kg slaughter weight showed a balance in terms of performance, carcass, and quality traits. Other combinations evaluated in this study showed potential to efficiently produce differentiated pork.

CHILLING RATE OF COOKED RICE AND RISK OF Bacillus cereus GROWTH IN RESTAURANT OPERATION

The emetic syndrome of B. cereus food poisoning is often connected with consumption of rice. When cooked rice is cooled slowly and stored between 10°C to 50°C B. cereus spores germinate and reach numbers high enough to cause illness. Cooked rice is often slowly chilled in most of the restaurants. In the absence of rapid cooling instruments such as blast chiller and cold room, cooked rice, as a common practice is kept at room temperature for cooling for a long time before putting into a refrigerator. In this study, cooked rice in 10 cm deep in a pan was chilled in a blast chiller, cold room, refrigerator and at ambient and the cooling rates between the temperature zone of 50oC to 10oC were determined. Except the chilling in a blast chiller, in no other chilling methods the instructed/recommended four hours chilling time was achieved. Chilling of rice from 50oC to 10oC in a refrigerator took 12.5-13.5 hours. Chilling time came down to around 10 hours when thickness of rice in the pan was reduced to 5 cm. Chilling time was much longer (15.5-16.5 hours) when the rice was held at ambient until the centre temperature was 30 oC before putting into the refrigerator. It is obvious that the commonly applied rice chilling in the restaurants is not safe. Some other practical ways other than reducing the thickness of rice should also be applied.

The right to food, food donation and microbiological problems of food safety: an experience in the territory of Florence.

The aim of this study is to understand whether the freezing without a rapid blast chiller represents a storage method for food at the end of shelf life that guarantees microbiological food safety, so to be considered an effective tool for the appropriate management of food in charitable organizations. The study has been performed on 90 food samples, among those that a charitable foodservice trust receives by the large-scale distribution. The products have been frozen using a domestic refrigerator. The indicators used were: total aerobic microbial count, Escherichia coli, Salmonella spp, Staphylococcus aureus, Campylobacter spp, sulphite reducing clostridia. The results show that the preservation of the chosen fresh products at the end of shelf life in refrigerators, frozen without the use of chillers, is a potential management strategy to avoid the loss of edible food, while maintaining the safety standards.

Effects of feeding high protein canola meal on dry cured and conventionally cured bacon

The aim of this study was to determine the effects of blast chilling of pig carcasses on the physiochemical and sensory properties of the longissimus lumborum muscle. To this end, right half-carcasses were blast-chilled for 70 min at − 24 °C and then for 22 h and 50 min at 1 °C, while left half-carcasses were chilled conventionally at 1 °C for 24 h. At 2 h and 6 h post mortem, blast chilling had significantly reduced the temperature of the carcasses, as well as the rate of pH decrease and the rate of increase in EC. It had no significant effect on the ultimate pH or its range, or on EC at 24 h post mortem, but it significantly lowered L*, b*, C* and drip loss compared to the conventionally chilled carcasses. Blast chilling adversely affected sensory characteristics such as tenderness and flavor. There were no significant differences between the effects of blast and conventional chilling systems on meat quality between conformation classes.

The effects of blast chilling on pork quality

The aim of this study was to determine the effects of blast chilling of pig carcasses on the physiochemical and sensory properties of the longissimus lumborum muscle. To this end, right half-carcasses were blast-chilled for 70min at −24°C and then for 22h and 50min at 1°C, while left half-carcasses were chilled conventionally at 1°C for 24h. At 2h and 6h post mortem, blast chilling had significantly reduced the temperature of the carcasses, as well as the rate of pH decrease and the rate of increase in EC. It had no significant effect on the ultimate pH or its range, or on EC at 24h post mortem, but it significantly lowered L*, b*, C* and drip loss compared to the conventionally chilled carcasses. Blast chilling adversely affected sensory characteristics such as tenderness and flavor. There were no significant differences between the effects of blast and conventional chilling systems on meat quality between conformation classes.