Quality changes in sea urchin (Strongylocentrotus nudus) during storage in artificial seawater saturated with oxygen, nitrogen and air

BACKGROUND: Sea urchin gonads are highly valued seafood that degenerates rapidly during the storage period. To study the influence of dissolved oxygen concentration on quality changes of sea urchin (Strongylocentrotus nudus) gonads, they were stored in artificial seawater saturated with oxygen, nitrogen or air at 5 ± 1 °C for 12 days. RESULTS: The sensory acceptability limit was 11–12, 6–7 and 7–8 days for gonads with oxygen, nitrogen or air packaging, respectively. Total volatile basic nitrogen (TVB‐N) values reached 22.60 ± 1.32, 32.37 ± 1.37 and 24.91 ± 1.54 mg 100 g^?1 for gonads with oxygen, nitrogen or air packaging at the points of near to, exceeding and reaching the limit of sensory acceptability, indicating that TVB‐N values of about 25 mg 100 g^?1 should be regarded as the limit of acceptability for sea urchin gonads. Relative ATP content values were 56.55%, 17.36% and 18.75% for gonads with oxygen, nitrogen or air packaging, respectively, on day 2. K‐values were 19.37%, 25.05% and 29.02% for gonads with oxygen, nitrogen or air packaging, respectively, on day 2. Both pH and aerobic plate count values showed no significant difference (P > 0.05) for gonads with the three treatments. CONCLUSION: Gonads with oxygen packaging had lower sensory demerit point (P < 0.05) and TVB‐N values (P < 0.05), and higher relative ATP content (P < 0.01) and K‐values (P < 0.05), than that with nitrogen or air packaging, with an extended shelf life of 4‐5 days during storage in artificial seawater at 5 ± 1 °C. Copyright © 2011 Society of Chemical Industry     

Evaluation of Changes in Listeria monocytogenes Populations on Frankfurters at Different Stages from Manufacturing to Consumption

ABSTRACT: This study evaluated the fate of inoculated Listeria monocytogenes on frankfurters stored under conditions simulating those that may be encountered between manufacturing and consumption. Frankfurters with or without 1.5% potassium lactate and 0.1% sodium diacetate (PL/SD) were inoculated (1.8 ± 0.1 log CFU/cm²) with a 10‐strain composite of L. monocytogenes, vacuum‐packaged, and stored under conditions simulating predistribution storage (24 h, 4 °C), temperature abuse during transportation (7 h, 7 °C followed by 7 h, 12 °C), and storage before purchase (60 d, 4 °C; SBP). At 0, 20, 40, and 60 d of SBP, samples were exposed to conditions simulating delivery from stores to homes or food establishments (3 h, 23 °C), and then opened or held vacuum‐packaged at 4 or 7 °C for 14 d (SHF). Pathogen counts remained relatively constant on frankfurters with PL/SD regardless of product age and storage conditions; however, they increased on product without antimicrobials. In vacuum‐packaged samples, during SHF at 4 °C, the pathogen grew faster (P < 0.05) on older product (20 d of SBP) compared to product that was fresh (0 d of SBP); a similar trend was observed in opened packages. At 7 °C, the fastest growth (0.35 ± 0.02 log CFU/cm²/d) was observed on fresh product in opened packages; in vacuum‐packages, growth rates on fresh and aged products were similar. By day 40 of SBP the pathogen reached high numbers and increased slowly or remained unchanged during SHF. This information may be valuable in L. monocytogenes risk assessments and in development of guidelines for storage of frankfurters between package opening and product consumption.     

Shelf Life Determination of Sliced Portuguese Traditional Blood Sausage—Morcela de Arroz de Monchique through Microbiological Challenge and Consumer Test

Morcela de Arroz (MA) is a ready‐to‐eat blood and rice cooked sausage produced with pork, blood, rice, and seasonings, stuffed in natural casing and cooked above 90 °C/30 min. It is commercialized whole, not packed, with a restricted shelf life (1 wk/0 to 5 °C). The objective of this work was to establish sliced MA shelf life considering both the behavior of L. monocytogenes through a microbiological challenge test (MCT) and the consumer acceptability of MA stored: vacuum packed (VP), modified atmosphere packed (MAP: 80% CO₂/20% N₂), and aerobic packed (AP). The MCT was conducted inoculating ±3 log CFU/g of L. monocytogenes cell suspension on the MA slices. Packaged samples were stored at 3 ± 1 °C and 7 ± 1 °C until 20 d. At 3 ± 1 °C, L. monocytogenes behavior was not affected by packaging or storage time. At 7 ± 1 °C, the pathogen increased nearly 1 log CFU/g in the first 4 d. L. monocytogenes populations in AP were higher (P < 0.05) than in MAP. The pathogen may grow to hazardous levels in the 1st days if a temperature abuse occurs. Considering the acceptability by the consumers, the shelf life of MA stored at 3 ± 1 °C was 4.4 d for AP, 8.1 d for VP, and 10.4 d for MAP. The sensory shelf life established based on sensory spoilage is shorter than the shelf life to maintain the population of L. monocytogenes in safe levels.     

Development of peanut milk–based fermented curd

Fermented milk product (Indian curd) was developed by using peanut milk. The level of incubation period (IP), skimmed milk powder (SMP), carboxymethyl cellulose (CMC) was optimised using response surface methodology (RSM). Central composite rotatable design was used with three independent variables i.e. IP (16–20 h), SMP (3–5%) and CMC (0.1–0.3%). SMP had significant (P ≤ 0.05) positive effect on overall acceptability (OAA) of curd because of increase in the total solids that ultimately increased firmness of the curd. CMC was found effective in reducing the synersis of curd samples. The developed curd samples had moisture 84.8 ± 0.28%, protein 3.2 ± 0.12%, fat 3.5 ± 0.10%, ash 0.5 ± 0.05%, carbohydrate 8.0% (wb), peak viscosity 291.4 ± 3.52 cP, firmness 1.3 ± 0.15 N, synersis 32.1 ± 0.2 mL 100 g^?1 and acidity (as % lactic acid) 0.58 ± 0.02. It had OAA score of 7.8 ± 0.2 on nine‐point hedonic scale. Based on compromise optimisation, the conditions recommended were IP as 18 h, SMP, 4.24% and CMC, 0.19% for making peanut milk–based fermented curd with 83.4% desirability.     

Culture Filtrates from a Fermented Rice Product (Lao-Chao) and Their Effects on Milk Curd Firmness

To develop a new Oriental-style dairy product, the characteristics of culture filtrate from lao-chao with Rhizopus oryzae, used as a milk-clotting agent, and factors (heat-treatments, calcium, sucrose, and curdling temperature) affecting curd firmness were determined. The optimal conditions for proteolytic activity were around 40°C and pH 3. No activity was detected over the range of pH 8 to 11. After high-heat treatment (121°C, 15 min) on skim milk, no clotting was observed. Sucrose resulted in the retardation of milk-clotting. Ca⁺⁺ could be used to increase curd firmness which also increased from 29. 2–2.8g to 80. 3–4.7g when the curdling temperature was increased from 25°C to 45°C.     

Application of Lactobacillus plantarum in Functional Products Based on Fermented Buckwheat

In this work, 12 plant‐based potential probiotic mashes were produced by fermenting buckwheat with lactic acid cocci of the Fresco DVS 1010 culture and the human‐derived isolate Lactobacillus plantarum HM1. The effect of single and coculture fermentation was studied at 30 and 37 ± 0.5 °C for 8 hr (5% CO₂), followed by a storage period of 21 days (6 ± 0.5 °C). Although milk is the typical growth medium for lactic acid bacteria (LAB), presumably viable counts of Fresco reached levels of 10⁸ to 10⁹ CFU/mL (specific growth rates ranging from 1.07 to 1.40 hr^?1) with higher counts in coculture fermentation (13%) that differed statistically significantly (P < 0.05). After storage, 194 to 4700 mg/kg lactic acid was found in the mashes, with significantly higher contents after cocultivation (11% to 96%). Based on the overall acceptance of the designed products, milk‐based mashes right after the fermentation were evaluated as the most satisfactory (3.3 to 3.6). Those after the storage period (21 days) exhibited an attractive sensory acceptability (2.2 to 3.2).     

Antioxidant properties and shelf‐life extension of fresh‐cut tomatoes stored at different temperatures

BACKGROUND: The feasibility of using modified atmosphere packaging (5 kPa O₂ + 5 kPa CO₂) to maintain the antioxidant properties of fresh‐cut tomatoes during shelf‐life was assessed through storage at different temperatures (5, 10, 15 and 20 °C). Health‐related compounds, antioxidant capacity, microbiological counts, physicochemical parameters and in‐package atmosphere of tomato slices were determined. RESULTS: Initial lycopene, vitamin C and phenolic contents and physicochemical parameters of tomato slices were well maintained for 14 days at 5 °C. Lycopene and total phenolic contents were enhanced over time in tomato slices stored at 15 and 20 °C. However, this increase in antioxidant compounds of fresh‐cut tomatoes during storage may be associated with excessive amounts of CO₂ (R² = 0.5679–0.7328) in the packages due to microbial growth. Although keeping tomato slices at temperatures above 10 °C increased their antioxidant content, the shelf‐life of the product was reduced by up 4 days. CONCLUSIONS: A storage temperature of 5 °C is appropriate for maintaining the microbiological shelf‐life of fresh‐cut tomatoes for up to 14 days and also allows the antioxidant properties of tomato slices to be retained over this period, thus reducing wounding stress and deteriorative changes. Copyright © 2008 Society of Chemical Industry     

The development of a goat's milk yogurt

This study sought to establish conditions suitable for a small‐scale yogurt process using goat's milk and to examine the physicochemical properties (pH, titratable acidity, solids‐not‐fat (SNF), viscosity, texture) and organoleptic acceptability (preference by Filipino panellists) of the resultant product. Goat's milk was concentrated by heating (80 °C, 1 h), which resulted in an increase in SNF from 85 to 110 g kg^?1. To further improve the curd of goat's milk yogurt, two hydrocolloids were used: carrageenan (1.5 and 3 g l^?1) and pectin (50 g l^?1). The addition of dehydrated pineapple and banana cubes (50 and 100 g l^?1) in a sundae‐style formulation increased the SNF by an additional 2.5% and produced a curd that was firmer than the control, plain set yogurt. The use of carrageenan appeared to be a convenient way of controlling product viscosity. In terms of product preference and firmness the fruit‐flavoured sundae‐style yogurts were ranked higher by sensory panellists. Copyright © 2005 Society of Chemical Industry     

E‐Beam Irradiation for Improving the Microbiological Quality of Smoked Duck Meat with Minimum Effects on Physicochemical Properties During Storage

This study was performed to evaluate the effect of different doses (0, 1.5, 3, and 4.5 kGy) of e‐beam irradiation on the quality parameters (pH, Hunter's parameter, and heme pigment) and stability qualifiers (peroxide value [POV], thiobarbituric acid reactive substances [ TBARSs], and total volatile basic nitrogen [TVBN]) of smoked duck meat during 40 d of storage under vacuum packaging at 4 °C. The initial populations of total bacteria (7.81 log CFU/g) and coliforms (5.68 log CFU/g) were reduced by approximately 2 to 5 log cycles with respect to irradiation doses. The results showed that pH, myoglobin, met‐myoglobin, L^*, a^*, and b^* showed significant differences with respect to different doses and storage intervals; a^* and b^* did not vary significantly because of storage. Higher pH was found in samples treated with 4.5 kGy at 40 d, while the minimum was observed in nonirradiated samples at day 0 of storage. Higher POV (2.31 ± 0.03 meq peroxide/kg) and TBARS (5.24 ± 0.03 mg MDA/kg) values were found in 4.5 kGy‐treated smoked meat at 40 d and the lowest was reported in 0 kGy‐treated meat at initiation of storage (0 d). However, irradiation suppressed TVBN during storage and higher TVBN (7.09 ± 0.32 mg/100 mL) was found in duck meat treated with 0 kGy at 40 d. The electronic nose (e‐nose) effectively distinguished flavor profiles during the different storage intervals. The results showed that different sensory attributes did not vary significantly with respect to the dose of irradiation. We conclude that low dose of e‐beam irradiation and vacuum packaging is beneficial for safety and shelf life extension without affecting the sensory characteristics of smoked duck meat.     

Influence of packaging strategy on microbiological and biochemical changes in high‐pressure‐treated oysters (Crassostrea gigas)

BACKGROUND: High‐pressure (HP) treatment is being increasingly employed for commercial processing of oysters, but there is relatively limited information on the microbiological quality and enzymatic activity of HP‐treated in‐shell oysters. The objective of this research was to study the influence of packaging strategy on microbiological and biochemical changes in oysters HP treated at 260 MPa for 3 min or 400 MPa for 5 min at 20 °C and stored at 0 °C either aerobically on ice, in vacuum packaging (VP) or under modified atmosphere packaging (MAP; 40% CO₂, 60% N₂), compared with changes in untreated oysters. RESULTS: Both HP treatments reduced the microbiological load to below the detection limit (<100 colony‐forming units g^?1). MAP and VP also delayed subsequent microbial growth compared with aerobically stored samples. After 21 days of storage, total volatile base levels remained lower than the proposed acceptability limits for all samples; however, after 28 days, only oysters HP treated at 400 MPa, irrespective of the packaging system used, did not exceed this limit. HP increased the thiobarbituric acid‐reactive substance (TBARS) values of oysters, indicating increased lipid oxidation. During storage, TBARS values of all MAP and VP oysters remained lower than those of aerobically stored oysters. CONCLUSION: HP treatment, in combination with adequate chilled storage and MAP, can extend the shelf‐life and safety of oysters. Copyright © 2008 Society of Chemical Industry     

An integrated strategy to control post-harvest decay of Embul banana by combining essential oils with modified atmosphere packaging

Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control post‐harvest diseases, packed under modified atmosphere (MA) using low‐density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 ± 1 °C, 90% RH) or at ambient temperature (28 ± 2 °C). The effects of the essential oils on post‐harvest diseases; physico‐chemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost‐effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 ± 2 °C without affecting the organoleptic and physico‐chemical properties.     

Effect of Hops Beta Acids on the Survival of Unstressed‐ or Acid‐Stress‐Adapted‐Listeria Monocytogenes and on the Quality and Sensory Attributes of Commercially Cured Ham Slices

This study evaluated the antilisterial activity of hops beta acids (HBA) and their impact on the quality and sensory attributes of ham. Commercially cured ham slices were inoculated with unstressed‐ and acid‐stress‐adapted (ASA)‐L. monocytogenes (2.2 to 2.5 log CFU/cm²), followed by no dipping (control), dipping in deionized (DI) water, or dipping in a 0.11% HBA solution. This was followed by vacuum or aerobic packaging and storage (7.2 °C, 35 or 20 d). Samples were taken periodically during storage to check for pH changes and analyze the microbial populations. Color measurements were obtained by dipping noninoculated ham slices in a 0.11% HBA solution, followed by vacuum packaging and storage (4.0 °C, 42 d). Sensory evaluations were performed on ham slices treated with 0.05% to 0.23% HBA solutions, followed by vacuum packaging and storage (4.0 °C, 30 d). HBA caused immediate reductions of 1.2 to 1.5 log CFU/cm² (P < 0.05) in unstressed‐ and ASA‐L. monocytogenes populations on ham slices. During storage, the unstressed‐L. monocytogenes populations on HBA‐treated samples were 0.5 to 2.0 log CFU/cm² lower (P < 0.05) than control samples and those dipped in DI water. The lag‐phase of the unstressed‐L. monocytogenes population was extended from 3.396 to 7.125 d (control) to 7.194 to 10.920 d in the HBA‐treated samples. However, the ASA‐L. monocytogenes population showed resistance to HBA because they had a higher growth rate than control samples and had similar growth variables to DI water‐treated samples during storage. Dipping in HBA solution did not adversely affect the color or sensory attributes of the ham slices stored in vacuum packages. These results are useful for helping ready‐to‐eat meat processors develop operational procedures for applying HBA on ham slices.     

Stability of betacyanin from red pitahaya (Hylocereus polyrhizus) and its potential application as a natural colourant in milk

The effects of temperature (30, 50, 85 and 100 °C) treatment and 10 weeks of refrigerated storage (4 °C) on the betacyanin content and colour stability of betacyanins from red pitahaya (Hylocereus polyrhizus) were investigated and compared to red beet (Beta vulgaris; E‐162) which was used as a control. Temperature treatment at 50 and 85 °C caused a greater reduction in betacyanin content (BC) in E‐162 compared to red pitahaya by inducing changes in betacyanin profile. The 10 weeks of refrigerated storage at 4 °C induced colour changes in betacyanins from red pitahaya and E‐162. In milk, betacyanins from red pitahaya presented a lower loss of BC and total colour changes (ΔE*) compared to E‐162. The microbial onset in milk containing betacyanins from red pitahaya and E‐162 was delayed up to day 5 of refrigerated storage at 4 °C compared to day 3 in plain milk. Milk containing betacyanins from red pitahaya showed better colour acceptability (3.89 ± 1.89) compared to E‐162 (6.10 ± 1.71). Hence, betacyanins from red pitahaya may be a potential natural functional colourant to simulate strawberry colour in milk.     

Storage temperature and packaging condition affect the total phenolic content and antioxidant activity of black soybeans and koji

In this study, powders of steamed black soybeans and the Aspergillus awamori‐fermented black soybeans (koji) were subjected to storage at 4 °C and 25 °C with or without deoxidant and desiccant for 120 days. It was found that total phenolic content and the antioxidant activity including the DPPH radicals scavenging effect, Fe²⁺‐chelating ability and reducing activity of the methanol extracts from black soybeans and koji decreased as the storage period was extended. Furthermore, storage temperature and packaging condition affected the antioxidant activity of the methanol extracts of black soybeans and koji. After 120‐day storage, extract from black soybeans holding at 4 °C with deoxidant and desiccant exhibited the highest residual of DPPH radicals scavenging effect, Fe²⁺‐chelating ability and reducing activity of 71.78%, 72.66% and 70.04%, respectively. Meanwhile, the highest residual of 77.78%, 81.71% and 85.05% respectively, was noted with extract from koji held at 25 °C with deoxidant and desiccant.     

Development of vacuum‐dried probiotic milk powder with Bacillus coagulans

The present study explored the possibilities of using Bacillus coagulans as a probiotic culture in vacuum‐dried milk powder. The operational drying temperature at 63 ± 2 °C under 0.7 kg/cm² pressure emerged as the best temperature at which to prepare dried milk powder within 4.5 h with a mean (±SEM) Bacillus coagulans B37 spore count of 8.78 ± 0.03 log cfu/g and moisture content of 4.82 ± 0.12%. The total spore counts in vacuum‐dried milk powder did not change (P > 0.10) at storage temperatures of 7 °C, 37 °C or 45 °C over a three‐month period.     

Effect of nano‐TiO2‐LDPE packaging on microbiological and physicochemical quality of Pacific white shrimp during chilled storage

Nano‐TiO₂‐modified low‐density polyethylene (NTLDPE) packaging was prepared by blending LDPE with nano‐TiO₂. The effects of NTLDPE packaging on quality of Pacific white shrimp during storage at 4 °C were investigated. Results showed that NTLDPE lowered the K value by 28.50%, while increased sensory score by 30.77% in comparison with the control. NTLDPE packaging retarded the decrease of whiteness and water holding capacity and the increase of melanosis score based on the signs of freshness and deterioration of shrimp. Furthermore, NTLDPE packaging reduced total viable counts (TVC) by 6.42% and total volatile basic nitrogen (TVB‐N) contents were 14.82% lower than that of control. TVB‐N content and TBARS value, as well as polyphenol oxidase activity and TVC, were maintained and shrimp remained a commercial acceptability for 8 days. The overall results indicated that NTLDPE packaging could preserve the quality and extend the shelf‐life of Pacific white shrimp.     

Influence of Injection, Packaging, and Storage Conditions on the Quality of Beef and Bison Steaks

The combined effects of injection, packaging (modified atmosphere packaging [MAP] with 70% O₂/ 30% CO₂ and vacuum packaging [VP]), storage temperature (‐1 °C and +4 °C), and storage time on the color, microbial and oxidative stability of beef and bison longissimus lumborum (LL) steaks were investigated. Beef LL steaks in MAP retained their bright red color longer than bison steaks. Bison steaks developed higher 2‐Thiobarbituric acid reactive substances (TBARS) during storage, and this might have influenced the resulting rapid loss of redness from the bloomed meat. Storage at ‐1 °C in MAP provided greater color stability and a longer storage life for both meat species studied. Injection of salt/phosphate had a beneficial effect on the color stability of steaks during retail display; however, this positive effect was more pronounced for bison steaks compared with those of beef. Steaks stored overnight under MAP before retail display maintained the highest a* values for up to 5 d compared with those stored under vacuum. MAP‐OV steaks generally maintained the highest OMB content for up to 5 d during retail display compared with those stored under vacuum. Nevertheless, OMB levels were significantly (P < 0.05) lower in bison steaks compared with those of beef irrespective of packaging treatments. Injected steaks and those stored at ‐1 °C had significantly (P < 0.05) higher OMB levels compared with non‐injected counterparts and those stored at +4 °C, respectively. MAP is an excellent option for short‐term storage due to its positive effects on meat color, but for longer storage, VP may be necessary. Storing meat under vacuum and then placing it under MAP just before retail display might be another option to increase shelf life.     

Rheological behaviour and colour changes of ginger paste during storage

Ginger paste was prepared from fresh ginger by addition of 8% common salt and citric acid. The paste was thermally processed and packed in glass, polyethyleneterephthalate or high‐density‐polyethylene containers and stored at 5 ± 1 and 25 ± 1 °C for 120 days. The rheological characteristics of the paste were studied by using a computer controlled rotational viscometer over the temperature range of 20–80 °C. Samples were subjected to a programmed shear rate, increasing linearly from 0 to 200 s^?1 in 3 min, followed by a steady shear at 200 s^?1 for 3 min and finally decreasing linearly from 200 to 0 s^?1 in 3 min. Ginger paste exhibited pseudoplasticity with yield stress and flow adequately described by the Herschel–Bulkley model. The yield stress decreased exponentially with process temperature and ranged between 3.86 and 27.82 Pa. The flow behaviour index (n) varied between 0.66 and 0.82 over the temperature range. Both consistency index and apparent viscosity decreased with increase in temperature and the process activation energies were found to be in the range of 16.7 to 21.9 kJ mol^?1. The effect of temperature was significant (P < 0.05) on the Hunter colour combination value of the paste during storage; however it was not affected by type of packaging material (P > 0.05). It is recommended that ginger paste is stored at 5 ± 1 °C in polyethyleneterephthalate or glass containers.     

Effects of Frozen Storage on Survival of Staphylococcus aureus and Enterotoxin Production in Precooked Tuna Meat

This study investigated the survival of Staphylococcus aureus in precooked tuna meat for producing canned products during frozen storage (?20 ± 2 °C) as well as its growth and enterotoxin production at 35 to 37 °C after the storage. Samples (50 ± 5 g) of precooked albacore (loin, chunk, and flake) and skipjack (chunk and flake) tuna were inoculated with 5 enterotoxin‐producing strains of S. aureus at a level of approximately 3.5 log CFU/g and individually packed in a vacuum bag after 3 h incubation at 35 to 37 °C. Vacuum‐packed samples were stored in a freezer (?20 ± 2 °C) for 4 wk. The frozen samples were then thawed in 37 °C circulating water for 2 h and incubated at 35 to 37 °C for 22 h. Populations of S. aureus in all precooked tuna samples decreased slightly (<0.7 log CFU/g) after 4 wk of storage at ?20 ± 2 °C, but increased rapidly once the samples were thawed and held at 35 to 37 °C. Total S. aureus counts in albacore and skipjack samples increased by greater than 3 log CFU/g after 6 and 8 h of exposure to 35 to 37 °C, respectively. All samples became spoiled after 10 h of exposure to 35 to 37 °C, while no enterotoxin was detected in any samples. However, enterotoxins were detected in albacore loin and other samples after 12 and 24 h of incubation at 35 to 37 °C, respectively. Frozen precooked tuna meat should be used for producing canned tuna within 6 to 8 h of thawing to avoid product spoilage and potential enterotoxin production by S. aureus in contaminated precooked tuna meat.     

Effect of dietary supplementation with vitamin E on characteristics of vacuum‐packed lamb

The effect of dietary vitamin E supplementation on lamb during vacuum‐packed storage was studied. Thirty‐six weaned male Manchego breed lambs were offered four dietary treatments (20, 270, 520 and 1020 mg vitamin E kg^?1 feed). Lambs were fed the vitamin E‐supplemented diet from 13 until 26 kg live weight. Pieces of M. longissimus dorsi were stored under vacuum at 2 ± 1 °C in the dark and meat quality was assessed after 5, 14 and 28 days of storage. Dietary supplementation significantly increased the α‐tocopherol concentration in the muscle (P < 0.001). Initially, lipid oxidation, meat colour and bacterial load were similar in all groups. In meat of non‐supplemented lambs the thiobarbituric acid reactive substance value increased throughout storage, whereas in meat of supplemented lambs it did not increase. Meat pigments and discolouration proportion were significantly affected by storage time (P < 0.001). The bacterial load was low initially, but after 28 days of storage it was close to 7 log₁₀ colony‐forming units (cfu) cm^?2 and Enterobacteriaceae surpassed the limit of acceptability of 2.5 log₁₀ cfu cm^?2, making the lamb unsuitable for human consumption. Meat of supplemented lambs displayed less lipid oxidation than that of their non‐supplemented counterparts, while meat colour and bacterial load were not affected by supplementation. Copyright © 2007 Society of Chemical Industry