Simulated Retail Conditions Research Articles

Disinfection effects of electrolyzed oxidizing water on suppressing fruit rot of pear caused by Botryosphaeria berengeriana

Chlorination presents one of the few chemical options available to help manage postharvest decay. Electrolyzed oxidizing (EO) water, containing free chlorine, is the product of a new concept developed by scientists in Japan. The effectiveness of pear ( Pyrus communis L.) immersion in EO water on the control of Bot. rot on European pear, cv. La-France, was investigated. Four independent experiments were carried out. A wound was found necessary for infection. Wounded fruit were inoculated with 20 μl spore suspension of 5×10 5 conidia/ml of Botryosphaeria berengeriana, incubated for 4 h, immersed in EO water, and held at 20 °C, ⩾90% relative humidity (simulated retail conditions) for ripening and disease development. No chlorine-induced phytotoxicity was observed on the treated fruit. EO water suppressed the incidence and disease severity. The minimum incidence and severity were recorded for a 10-min immersion period. This study revealed that EO water is an effective surface sanitizer.

Reduction of E. coli, Salmonella typhimurium, coliforms, aerobic bacteria, and improvement of ground beef color using trisodium phosphate or cetylpyridinium chloride before grinding

The impact of 10% trisodium phosphate (TSP) or 0.5% cetylpyridinium chloride (CPC) applied to beef trimmings either aerobically or under vacuum before grinding on Salmonella typhimurium (ST), Escherichia coli (EC), coliform (CO), aerobic plate count (APC), color and sensory attributes of ground beef through display was studied. For this, beef trimmings were inoculated with ST and EC then treated with either TSP or CPC in vacuum or aerobic conditions. Trimmings were ground, packaged, displayed under simulated retail conditions and sampled on days 0, 1, 2, 3 and 7 for microbial, instrumental color, and sensory color and odor characteristics. Aerobic and vacuum antimicrobial application methods were equally effective ( P>0.05) for reducing microorganisms in ground beef. Trisodium phosphate and CPC reduced ( P<0.05) all bacterial types monitored. In addition, TSP and CPC improved ( P>0.05) ground beef redness ( a*), oxymyoglobin stability (630 nm/580 nm) and sensory overall color throughout display without adversely affecting odor characteristics.

Fungicidal Effectiveness of Electrolyzed Oxidizing Water on Postharvest Brown Rot of Peach

The fungicidal effectiveness of electrolyzed oxidizing (EO) water on peach [Prunus persica (L.) Batsch.] fruit was studied. Fruit were inoculated with a spore suspension of 5 × 105 conidia/mL of Monilinia fructicola [(G. Wint.) Honey] applied as a drop on wounded and nonwounded fruits, or by a uniform spray-mist on nonwounded fruits. Fruit were immersed in tap water at 26 °C for 5 or 10 minutes (control), or treated with EO water varying in oxidation-reduction potential (ORP), pH, and free available chlorine (FAC). Following treatment, fruit were held at 20 °C and 95% relative humidity for 10 days to simulate retail conditions. Disease incidence was determined as the percentage of fruits showing symptoms of the disease, while severity was expressed as lesion diameter. EO water did not control brown rot in wound-inoculated fruits, but reduced disease incidence and severity in nonwound-inoculated peach. Symptoms of brown rot were further delayed in fruit inoculated by a uniform-spray mist compared with the nonwounded-drop-inoculated peaches. Fruit treated with EO water held for 8 days at 2 °C, 50% RH, did not develop brown rot, until they were transferred to 20 °C, 95% RH. The lowest disease incidence and severity occurred in fruit immersed in EO water for up to 5 minutes. EO water having pH 4.0, ORP 1,100 mV, FAC 290 mg·L-1 delayed the onset of brown rot to 7 days, i.e., about the period peach stays in the market from a packing house to consumer. No chlorine-induced phytotoxicity was observed on the treated fruit. This study revealed that EO water is an effective surface sanitizer, but only delayed disease development.

The influence of packaging methodology on the microbiological and fatty acid profiles of refrigerated African catfish fillets.

The shelf-life of refrigerated catfish fillets was determined at 2 degrees C, to simulate retail conditions, using two types of packaging materials, vacuum packing (VP) and oxygen permeable packaging (OPP). Representative samples (n=5) from both types of packaging methods were drawn at random every 2 d until a microbiological count of 106 cfu g-1 was reached. Samples were pooled and screened microbiologically using standard methods. Fatty acid analyses of total lipids, neutral lipid, glycolipid and phospholipid fractions were also conducted, to determine at which point the fish was regarded as spoiled and which packaging method provided a longer shelf-life. OPP limits storage to a maximum of 4 d (aerobic plate count of 8.2 x 105 cfu g-1), whereas VP extends the shelf-life of the fillets to between 6 and 8 d (aerobic plate count of 9.2 x 104 cfu g-1 and 1.66 x 106 cfu g-1, respectively). Similarly, coliform counts increased with time; however, packaging material had no statistical influence thereon. Until d 13, when the experiment was terminated, no deterioration in lipid composition of the various fractions was noted. An extended shelf-life microbiologically-speaking, for potential processors, could thus be obtained by using VP instead of OPP.

SHELF‐LIFE AND QUALITY OF‘NAVAHO’ AND ‘SHAWNEE’ BLACKBERRY FRUIT STORED UNDER RETAIL STORAGE CONDITIONS1

ABSTRACTThe quality of soft‐fruited (‘Shawnee’) and firm‐fruited (‘Navaho’) blackberry cultivars held under simulated retail conditions was determined. Leakage and decay increased during storage and exceeded 20% in 'Shawnee’ fruit after 14 days at 2C or 7 days at 5C, while ‘Navaho’ held under similar conditions was still marketable (&lt;10% decay). Transferring fruit to 20C for 2 days after low temperature storage intervals was detrimental to fruit quality, resulting in increased weight loss, leakage, decay and softening in both cultivars. After retail warming, ‘Shawnee’ fruit lost 25% of marketable fruit while‘Navaho’ had a 10% loss. Soluble solids concentration did not change significantly during storage, but titratable acidity declined 40–50%. Anthocyanin content increased from 20–100% depending on cultivar, storage temperature and storage intervals. The sugar composition of blackberries before storage was about 10, 260 and 260 mg/g dry weight, glucose, and fructose, respectively. Sucrose and glucose decreased and fructose increased slightly during storage. Warming fruit after low temperature storage did not accelerate loss of total sugars. If held constantly at 2C, ‘Navaho’ could be held 21 days.

The effect of dietary vitamin E and controlled atmosphere packaging on the storage life of beef

The effects of dietary vitamin E upon colour, bacteriology and case life of beef was examined following extended storage of longissimus thoracis (LT) muscle in vacuum or in anoxic atmospheres containing 100% CO2 The diets of treated steers were supplemented with 1000 IU of vitamin E animal−1 d−1 for 100 d. Animals were slaughtered in a research abattoir and after 24 h of postmortem aging the LT muscles were removed and assignedto a packaging treatment for storage for up to 11 wk at 2 °C. Rib-eye steaks were cut and displayed under simulated retail conditions to give a surface temperature of 6 °C after storage intervals of 0, 3, 6, 9 and 11 wk. Feeding treatment had no effect (P &gt; 0.05) upon standard carcass and muscle quality traits or bacterial growth but increased carcass α-tocopherol levels from 2.89 µg g−1 in control animals to 5.18 µg g−1 in carcasses supplemented with vitamin E (P &lt; 0.0001). The α-tocopherol concentration in LT muscles was unaffected (P &gt; 0.05) by storage time for up to 11 wk in either packaging treatment. Dietary vitamin E increased a* values and reduced metmyoglobin accumulation after LT storage for up to 11 wk irrespective of package atmosphere. However, dietary vitamin E had no significant effect (P &gt; 0.05) on the colour case life of steaks derived from the LT muscle after vacuum storage for 3 to 11 wk. Contrarily, vitamin E acted synergistically with the CO2 packaging treatment to produce an increase in colour case life from 2.7 (control) to 5.4 d (vitamin E) after 6 wk of LT storage and from 2.4 (control) to 4.0 d (vitamin E) after 9 wk of LT storage (P &lt; 0.0001). In combination with anoxic, CO2 packaging, dietary vitamin E may play a role in assuring beef colour stability following extended periods of storage necessary for fresh beef export. Key words: Vitamin E, packaging, beef storage

Influence of hot-processing and electrical stimulation on the bacteriology and retail case-life of vacuum packaged lamb

Carcasses from 48 wether lambs 6 to 9 months of age were utilized to evaluate the effects of hot-processing and electrical stimulation on bacterial numbers and types of bacteria on lamb cuts, following vacuum packaged storage and during simulated retail display. Carcasses were subdivided into groups of 16. One subgroup was processed conventionally or chilled for 24 h at 1 °C. Another subgroup was electrically stimulated (20; 2 s pulses interspersed with 1 s resting intervals; 550V, AC, 50–60 cycles/s) at approximately 45 min post mortem and then chilled conventionally at 1 °C until 24 h post mortem. The final subgroup was treated identically to the subgroup receiving electrical stimulation, but was hotboned immediately following stimulation, vacuum packaged, and chilled at 1 °C until 24 h post mortem. At 24 h post mortem the racks from conventional and electrically stimulated carcasses were removed and vacuum packaged. All vacuum packaged racks were then randomly allocated to four post mortem storage intervals (0, 14, 28 and 42 days) within processing treatments, so that four racks from each processing treatment were evaluated at each storage interval. Following storage for the designated intervals, racks were fabricated into chops. The two centre chops from each rack were placed into styrofoam trays, overwrapped with oxygen permeable film and displayed under simulated retail conditions for 5 days. Racks were sampled for bacteriological analyses before and immediately after storage and chops were sampled before and after 5 days of simulated retail display. Four bacterial groups were enumerated (psychrotrophs, pseudomonads, lactics and Brochothrix thermosphacta). Processing treatments were not found to have any consistent effects upon bacterial populations except for the absence of B. thermosphacta on hot-boned and electrically stimulated racks. Neither storage time nor processing treatment produced a significant effect on retail case-life. Consequently, lamb carcasses can be processed using electrical stimulation and hot-boning alone or in combination to increase processing efficiency; and cuts can be stored in vacuum for up to 42 days without reducing the case-life of retail cuts below an acceptable level of 2 to 3 days.

Storage response of cactus pear fruit to CaCl2preharvest spray and postharvest heat treatment

SummaryCactus pear fruit (Opuntia ficus-indica Mill. cv. Gialla) were treated ten weeks after full bloom with 2% CaCl2 solution and heated at 38°C for 24 h under saturated humidity after harvest. The two treatments were also combined before storage at 6°C for 42 d plus three additional days at 20°C to simulate retail conditions. Control fruit were untreated with CaCl2 and unheated. CaCl2 treatment delayed the appearance of the typical colour of ripe fruit, decreased the rate of fruit weight loss during simulated marketing and significantly inhibited pathogen development by the end of cold storage and subsequent simulated marketing period (SMP) but significantly promoted the appearance of chilling injury (CI) during SMP. Prestorage heat treatment (HT) reduced rot development during cold storage and after, reduced chilling injury incidence during storage and reduced the decline in overall appearance. The combined treatments (CaCl2 + HT) did not exhibit advantages in mould decay control as compared with HT applied separately. HT applied alone or in combination with CaCl2 significantly increased ethylene production rate by the end of SMP. The influence of treatments on respiration rate, pH of juice, titratable acidity, total soluble solids, acetaldehyde and ethanol concentrations in the juice was negligible, both during cold storage and SMP.

Color coordinates for assessment of dietary vitamin E effects on beef color stability.

Color stability was investigated in longissimus lumborum (LL), semimembranosus (SM), and gluteus medius (GM) muscles from Holstein steers fed diets including doses of alpha-tocopheryl acetate that were 0 (EO), 250 (E250), 500 (E500), and 2,000 (E2000) mg.steer-1.d-1 for 42 or 126 d. Longissimus lumborum was aged for 14, 28, and 56 d and GM and SM were aged for 14 d. Effects of vitamin E dose on retention of redness (a*), yellowness (b*), color saturation (chroma), and proportions of redness and yellowness (hue angle) following an aging period of 14 d were E2000 > E500 = E250 > EO (P < .01). Effectiveness of dose duration on the color parameters was 126 d > 42 d (P < .01). Dietary vitamin E supplementation stabilized redness and color saturation, decreased yellowness, and extended color display life of fresh beef. A technique for estimation of color display life based on hue angle measurements of fresh beef is described. Color display life estimates based on hue angle measurements were more consistent with vitamin E supplementation effects on metmyoglobin percentage and hue angle than were estimates obtained from the metmyoglobin threshold method. Color display life across LL, SM, and GM stored until d 14 and then displayed under simulated retail conditions was extended (P < .01) 2.0 (E250) to 5.0 d (E2000). Coefficients of determination for regressions of color display life on muscle alpha-tocopherol concentration were .81, .64, and .63 in LL, SM, and GM muscles aged 14 d, respectively. Supplementation of 500 mg of alpha-tocopheryl acetate per steer daily improved (P < .01) the mean color display life of these three muscles by 2.3 d, or 100%.

Dietary Supplementation of Vitamin E to Feedlot Cattle Affects Beef Retail Display Properties

ABSTRACTBeef products from carcasses (n = 20) of cattle fed supplemental vitamin E and beef products from commodity carcasses (n = 20), used as controls, were compared to determine effects of increased vitamin E tissue levels on display appearance of fresh beef held in supermarket and simulated retail conditions. Meat from cattle fed supplemental vitamin E contained higher levels of α‐tocopherol (P &lt; 0.05) and, over time, exhibited less lipid oxidation, brighter lean color and lower discoloration. Monitoring supermarkets for discounted retail meats showed increased levels of α‐tocopherol in beef extended caselife and decreased the incidence of discounted beef products.

Dietary α‐Tocopheryl Acetate Enhances Beef Quality in Holstein and Beef Breed Steers

ABSTRACTThe effect of long‐term feeding (252 days) of three supplemental levels of α‐tocopheryl acetate (actual 0, 360 and 1290 IU/head/day) on meat quality was evaluated in Holstein and beef breed steers. Tissue vitamin E concentrations were increased by each increment of supplementation. The color display life of fresh beef under simulated retail conditions was extended 2 to 5 days by vitamin E and lipid oxidation was markedly reduced. Microbial population was not affected by level of supplementation. No deterioration in sensory quality occurred for steaks from supplemented steers that were displayed until the time steaks from unsupplemented steers discolored.

Postharvest Performance of Southern Highbush Blueberry Fruit

The postharvest performance of early ripening southern highbush blueberries `Sharpblue' and `Gulfcoast' was evaluated under storage and simulated retail conditions. In general, `Gulfcoast' fruit were 28% heavier than those of `Sharpblue', which had a higher percent soluble solids concentration (SSC) and lower titratable acidity (TA). Quality loss, as indexed by fresh weight, percent decayed fruit, or changes in SSC, pH, or TA, was insignificant in first-harvest fruit of either cultivar when kept in storage (2C) for up to 7 days. Transfer of fruit stored at 2C for 3 days to simulated retail conditions at 21C for 4 days significantly increased fresh weight loss and decay, but not beyond levels deemed unmarketable. Second-harvest fruit were smaller than first-harvest fruit, and those of `Sharpblue' fruit were more prone to decay. However, storage quality of both cultivars was acceptable through 11 days at 2C. Retail quality, as influenced by decay incidence, was acceptable after 3 days at 2C plus 4 days at 21C, but not after 3 days at 2C plus 8 days at 21C. Overall, fruits of these early ripening southern highbush blueberry cultivars performed well under postharvest conditions and are suitable for expanding production of premium fresh blueberries by growers in the Gulf coastal plains.

Lean color characteristics of bullock and steer beef.

Twelve young bulls and 12 steers were slaughtered and the carcasses were fabricated at 48 h postmortem. Top rounds, bottom rounds, and rib eyes were vacuum-packaged and stored at 0 degrees C until 21 d postmortem. After subprimal storage, steaks were removed from each cut and displayed under simulated retail conditions for 3 d. Consumer panelists (n = 110) showed little difference in buying preference for top round, bottom round, and rib eye steaks from steers vs bullocks. Also, consumer panelists could not detect color differences between steaks from steers and bullocks. Experienced panelists (n = 6) detected brighter (P less than .05) muscle color for top round and rib eye steaks from steers but detected no difference in muscle color of bottom round steaks from bullocks and steers. Generally, overall desirability scores favored steaks from steer carcasses. This was particularly true of rib eye steaks. Sex-class of carcass did not affect aerobic plate counts of top round, bottom round, or rib eye steaks either before or after 3 d of retail display. Muscle pH was lower for top round and rib eye steaks from steer carcasses; however, the magnitude of this difference was not large enough to affect retail display stability. Muscle pH of bottom round steaks was not affected by sex-class. Although experienced panelists could detect differences in visual appearance of beef retail cuts from steers and bullocks, consumer panelists did not show a clear purchase preference for steer vs bullock beef. These data suggest that beef retail cuts from bullocks are acceptable in visual appearance.

Inability of a bacteriophage pool to control beef spoilage

The biological control of beef spoilage, with a bacteriophage (phage) pool, was evaluated under simulated retail conditions. A pool of seven phages was selected with the potential to lyse 78% of 86 Pseudomonas test strains. Subsequent host range studies with 1023 pseudomonads from three meat species (beef, pork, lamb) and five abattoirs showed that 585 (57.2%) isolates were susceptible to the phage pool. Depending on bacterial origin, bacterial sensitivity to lysis by the phage pool varied from 25 to 72%. When added to ribeye steaks, the phage pool produced a significant reduction in Pseudomonas growth but this was not sufficient to produce any significant effect upon the retail shelf life of beef. The inability of phages to control beef spoilage was not attributed to a loss of phage virulence since sufficient densities (log pfu/cm 2 = 5 to 6) of virulent phage could be re-isolated from beef, 14 days after treatment. It was concluded that the efficacy of the current phage pool was limited by a narrow range of specificity.

Shelflife Characteristics of Bacon Processed with Various Levels of Sodium Nitrite and Potassium Sorbate

Shelflife characteristics of lean color, lean surface discoloration and off-odor were evaluated on vacuum-packaged sliced bacon processed under commercial operations in four separate plants. In addition to the normal processing variations at each plant, three formulations with various levels of sodium nitrite and potassium sorbate were used: (a) 0 ppm sodium nitrite, (b) 40 ppm sodium nitrite-2600 ppm potassium sorbate and (c) 120 ppm sodium nitrite. Bacon was evaluated after 0, 2 and 4 d of simulated retail conditions following 10, 30, 50 and 70 d of storage under refrigerated dark conditions. Bacon processed with 0 ppm sodium nitrite underwent more lean surface discoloration than bacon processed with the other two formulations. The amount of lean surface discoloration, presence of undesirable colors and off-odor scores were similar between the 40 ppm sodium nitrite-potassium sorbate formulation and the 120 ppm sodium nitrite formulation except for the plant which employed a low salt-high sugar formulation. In this situation, especially with longer periods of storage and retail display, the 120 ppm sodium nitrite formulation yielded less surface discoloration, a lower frequency of undesirable colors and less off-odor than the 40 ppm sodium nitrite-2600 ppm potassium sorbate formulation. The occurrence of off-odor generally increased uniformly as a function of longer storage time regardless of sodium nitrite-potassium sorbate levels and processing plant variations.

Effect of Prerigor Pressurization on the Retail Characteristics of Beef

ABSTRACTLoin steaks were obtained from eight utility cows and ground beef from the bottom round of four choice steers. One side was randomly assigned to be prerigor pressurized (PRP) and the other side served as control (CON). Steaks and ground beef were displayed under simulated retail conditions for 5 and 3 days, respectively. PRP significantly improved lean color of the steaks for the first 4 days of display period. PRP steaks were significantly less discolored at the 5th day. No significant difference for any of the measured traits was observed for samples of ground beef. PRP had no detrimental effect on the case‐life of steaks or ground beef.

Growth of Staphylococcus aureus on Beef Steaks as Influenced by Type of Packaging

Beef loin steaks were inoculated with 105 cells of Staphylococcus aureus/cm2 in two separate trials to determine the effects of different packaging treatments upon the organism's growth. Each trial utilized 72 samples which were randomly assigned to four packaging treatments: (1) over-wrapped in oxygen-permeable film; (2) vacuum packaged; (3) packaged in barrier bags flushed with a 60% CO2 : 40% O2 gas atmosphere then evacuated and sealed; and (4) packaged in barrier bags filled with a 60%CO2 : 40% O2 gas atmosphere. In each treatment group, 12 samples were inoculated with S. aureus while 6 were uninoculated and used as controls. All samples were displayed under simulated retail conditions at 10 C and enumerated for S. aureus after 3, 6 and 9 days. Numbers of S. aureus remained relatively constant for all treatments throughout the 9 day period. Results from a comparison of treatments for Trials I and II were variable; however, no significant treatment effects were found when data from both trials were pooled.

Packaging of Beef Loin Steaks in 75% O2 Plus 25% CO2. II. Microbiological Properties

Numbers and types of bacteria were determined on steaks after refrigerated storage (1 ± 1 C) in 75% O2 plus 25% CO2 for 9 days in the dark plus display at 2 ± 2 C for 4 days under simulated retail conditions. Steaks were prepared from strip loins (IMPS #180) as received from the supplier (trial 1) and also from the same or similar loins that were vacuum-packaged at day 0 (trial 1) and then stored under refrigeration for 14 (trial 2) or 28 days (trial 3). Initially (day 0, trial 1), the microflora of steaks consisted primarily of Micrococcus and Moraxella-Acinetobacter sp. Following refrigerated storage in vacuum packages for either 14 or 28 days, Lactobacillus and Leuconostoc sp. became dominant. Refrigerated storage and display of steaks in 75%O2 plus 25% CO2 shifted the microbial population in favor of Leuconostoc sp. Initial log counts of steaks (day 0, trial 1) ranged from 0.88 to 2.02. Counts of steaks stored for 9 or 13 days in 75% O2 plus 25% CO2 nearly always exceeded 106 per cm2 when steaks were prepared from loins which had been stored in vacuum packages for either 14 or 28 days. The pH values of steaks prepared from loins which had been stored under refrigeration for 14 days were lower (0.27–0.56) than those of steaks prepared from comparable loins as they were received from the supplier (day 0, trial 1). Refrigerated storage of vacuum-packaged loins for an additional 14 days did not cause marked changes in pH of the steaks. No consistent differences in microbial flora were detected between green- and normal-pigmented areas of steaks prepared from vacuum-packaged loins which had been stored refrigerated for 14–28 days.

RETAIL APPEARANCE OF ELECTRICALLY STIMULATED BEEF

ABSTRACTTop round steaks (adductor) and ground beef from the top round were obtained from both sides of ten U.S. Choice carcasses. Left sides were electrically stimulated (ES) with 17 impulses (1.8 set duration, 1.8 set interval) of 550 volts of alternating current at 5 amps. Steaks and ground beef from top rounds from nonstimulated right sides served as control (CON) samples. Steaks and ground beef were displayed under simulated retail conditions for 4 and 3 days, respectively. Steaks were weighed prior to and at the termination of the display interval to determine percentage weight loss. Samples for microbiological evaluation were obtained prior to and at the termination of the display interval. No significant differences were observed for muscle color, surface discoloration or overall appearance for samples of ground beef at any retail display interval. With one exception, muscle color was brighter and surface discoloration was reduced for round steaks from ES sides. Few significant differences in overall appearance were observed between ES and CON samples during the display period. No significant differences between ES and CON samples were observed for bacterial counts either initially or at the termination of the display period for either steaks or ground beef samples. Percentage weight loss was not significantly different between ES and CON steaks. These data suggest that electrical stimulation may enhance, and certainly does not detract from, the appearance of round steaks displayed under retail market conditions.

CHEMICAL COMPOSITION OF CHOPS FROM PALE, SOFT, EXUDATIVE (PSE) AND NORMAL PORK LOINS

ABSTRACTChops from normal or pale, soft and exudative (PSE) pork loins were displayed under simulated retail conditions, and drip was collected. During display, drip from chops was greater for PSE than normal loins, but the drip from both types of chops contained similar concentration of protein, free amino acids, total amino acids, sodium, potassium, calcium and magnesium. However, loss per kg lean was higher in the PSE chops for protein (P &lt; 0.01) and potassium, calcium and magnesium (P &lt; 0.05). The lean tissue from PSE chops contained more protein but less ether extract and energy than did lean from normal chops. Differences between PSE and normal chops were not significant for dry matter, ash, sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc, free amino acids or total amino acids.