NUTRITIONAL, PROXIMATE, AND MICROBIAL CHARACTERISTICS OF PHOSPHATE PROCESSED SEA SCALLOPS (PLACOPECTEN MAGELLANICUS)

Sea scallop adductor muscles were used to evaluate six scallop processing methods with regards to changes in moisture content, nutritional equivalency, and total plate counts. Sodium tripolyphosphate (STP) reduced the rate of moisture incorporation, enhanced scallop moisture binding capacity and maintained a degree of antimicrobial capacity. Scallop moisture content increased with processing time. Short processing times using a higher concentrated STP solution performed as well, or better, in binding moisture and reducing bacteria than longer processing times using a lower concentrated STP solution. Increasing moisture content decreased nutrient levels on a per weight basis. Nutrients most affected by increasing moisture content were protein, niacin, calcium, and vitamin B₁₂. Moisture loss due to freeze/thaw or cooking concentrated some nutrients (protein and minerals), while contributing to the loss of water-soluble nutrients. The use of STP lowered scallop drip loss, which in turn, reduced nutrient loss.     

MICROBIAL, CHEMICAL AND PHYSICAL CHANGES IN CHILL WATER TREATED WITH ELECTROCHEMICAL METHOD

A three‐zone (anode, neutral, and cathode) electrochemical treatment chamber was designed and built to evaluate the inactivation of Salmonella typhimurium in poultry chill water. The chill water in the three‐zone chamber containing ～10⁶ CFU/mL S. typhimurium and 0.5% or 1.0% NaCl was treated at 15 or 25 mA/cm², and a temperature of 5–10C for up to 10 min. The Salmonella were inactivated within 0.5 to 4 min in the anode zone depending on the salt concentration and current density, slower inactivation rate in the cathode zone, and almost no inactivation in the neutral zone. The pH decreased to ～ 2 in anode zone, but increased to ～ 10 in the cathode zone. Temperature increased by 2–6.5C in the three zones depending on current density and salt concentration. The conductivity increased in the anode and cathode zones but little change in the neutral zone. The generated chlorine was proportional to the current density and the treatment time.     

SODIUM LACTATE AND SODIUM TRIPOLYPHOSPHATE EFFECTS ON OXIDATIVE STABILITY AND SENSORY PROPERTIES OF PRECOOKED REDUCED-FAT PORK SAUSAGE WITH CARRAGEENAN

One 40%-fat, three 10%-fat, and three 17%-fat ground pork sausage products were manufactured. Within each reduced-fat level, these products contained 0.5% carrageenan, carrageenan and 3% sodium lactate (SL), and carrageenan, SL and 0.25% sodium tripolyphosphate (SP). Precooked patties packaged with oxygen-permeable PVC film were stored at 4C and −20C for up to 6 days and 252 days, respectively. Vacuum-packaged patties were stored up to 84 days and 252 days at the respective temperatures. All reduced-fat products were harder, more dense, and less juicy than the 40%-fat product. Total aerobic microbial plate counts determined on PVC-packaged samples stored at 4C were similar among the 7 products. SL acted as a prooxidant as evaluated by 2-thiobarbituric acid values. SP used with SL tended to overcome the prooxidive effect of SL but increased springiness, hardness, and fracturability sensory scores.     

MICROBIAL, INSTRUMENTAL COLOR AND SENSORY CHARACTERISTICS OF GROUND BEEF PROCESSED FROM BEEF TRIMMINGS TREATED WITH POTASSIUM LACTATE, SODIUM METASILICATE, PEROXYACETIC ACID OR ACIDIFIED SODIUM CHLORITE AS SINGLE ANTIMICROBIAL INTERVENTIONS

Beef trimmings, inoculated with Escherichia coli (EC) and Salmonella typhimurium (ST), were treated with 3% potassium lactate (K-L), 4% sodium metasilicate (NMS), 0.1% acidified sodium chlorite (ASC) or 0.02% peroxyacetic acid (PAA) prior to grinding. The ground beef packages were sampled at 0, 1, 2, 3 and 7 days of simulated retail display. All treatments reduced ( P <  0.05) EC, coliforms and aerobic plate counts up to and some in excess of 1 log and ST count  ≥  1.5 logs. Sensory panelists found ground beef from all treatments to generally be similar ( P >  0.05) to the control in odor and similar ( P >  0.05) in color for the K-L and NMS treatments during initial display. Instrumental color results indicated that K-L, NMS and PAA were similar ( P >  0.05) in redness ( a* ) to the control. These findings indicated that use of tested antimicrobial agents can reduce microbial numbers with little impact on sensory odor and color characteristics.

PRACTICAL APPLICATIONS

Although antimicrobial interventions have shown promising results in decontaminating meat products, there are only a limited number of antimicrobial products that can be used without causing adverse effects on quality characteristics of the final product. Consumers often discriminate against discolored meat products, and thus any deleterious effects on color and other quality attributes in decontaminated products will lead to a negative economic impact. The outcome of this research will provide information on selection of antimicrobial agents that will maximize ground beef safety without causing deleterious effects on quality attributes. Application of suitable antimicrobial interventions at the end of a production line will be advantageous to supply ground beef with increased shelf-life and decreased or no risk for illnesses caused by pathogens.     

SODIUM LACTATE EFFECTS ON MICROBIAL, SENSORY, AND PHYSICAL CHARACTERISTICS OF VACUUM-PACKAGED PORK SAUSAGE

Vacuum-packaged fresh meat products held at refrigeration temperatures have limited shelf-life expectancies, often due to growth of anaerobic lactic acid-producing bacteria. Agents that can suppress the growth of this group are beneficial. Fresh pork sausage, formulated to contain 0%, 1%, 2%, or 3% sodium lactate (SL), was vacuum packaged and stored at 4C for 0, 10, 17, 24, and 31 days. A trained sensory panel evaluated pork, salty, sour, and bitter flavors. Aerobic total plate counts (APC), anaerobic total plate counts (AnPC), aerobic lactic acid producers (ALC), anaerobic lactic acid producers (AnLC), TBA values, and pH were determined. SL depressed APC, AnPC, and AnLC. Addition of 1% SL extended shelf-life of vacuum-packaged fresh pork sausage by 1 week compared to controls; samples containing 2% and 3% SL had not reached spoilage level (log₁₀ 7.0 CFU/g) at the conclusion of this study. Addition of SL increased salty taste and prevented loss of pork flavor over time, but had no effect on sour or bitter flavors.     

QUALITY CHANGES IN ICE-STORED TROPICAL WIRE-NETTING REEF COD (EPINEPHELUS MERRA)

The sensory, bacteriological and biochemical qualities of tropical wire‐netting reef cod (Epinephelus merra) stored in melting ice were studied. The total bacterial load in immediately iced (II) fish was 10 ⁶ cfu /g on the 17th day of storage. The histamine formers were 10 ¹ cfu /g on the initial day, whereas the total lactics was 10 ¹ cfu /g on the third day. The total coliforms decreased from MPN 35 to 0 per gram, while the anaerobic sulfite reducers did not exhibit any consistent trend. The fish delayed for 6 h before icing or delayed iced (DI) fish exhibited bacterial loads of 10 ⁶ cfu /g on the third day, while the total lactics ranged from 10 ¹to 10 ² cfu /g and the histamine formers ranged from 10 ²to 10 ⁴ cfu /g. The total coliforms declined and the anaerobic sulfite reducers increased over a period of 5 days. The pH and hypoxanthine increased during the storage. Both the total volatile base nitrogen and trimethylamine nitrogen attained the maximum limit of acceptability at the end of the storage. The fatty acid content was 0.17% as oleic acid even on the 17th day in II fish. The II fish exhibited a longer shelf life (17 days) when compared to the shorter shelf life (3 days) exhibited by the DI fish.     

POSTMORTEM CHANGES IN QUALITY INDICES OF ICE-STORED FLOUNDER (PARALICHTHYS PATAGONICUS)

The characteristics of flounder (Paralichthys patagonicus) were evaluated during a 12‐day period of storage in ice by monitoring the biochemical, microbiological and sensory parameters. The adenosine‐5′‐triphosphate and adenosine‐5′‐diphosphate were not detected, and the initial content of adenosine‐5′‐monophosphate (AMP) rapidly decreased to zero. Inosine‐5′‐monophosphate (IMP) but not adenosine (Ado) was present in muscle extracts. The AMP deaminase activity was found in the muscle. Conversely, the Ado deaminase activity was not detected. A 55% decrease in IMP concentration occurred during the first 2 days of storage. The inosine content was barely detectable (<0.1 μmol/g), probably because of the high nucleoside phosphorylase activity in the muscle. Hypoxanthine significantly (P < 0.01) increased up to the seventh day and then remained approximately constant. The muscle pH fluctuated between 6.6 and 7.0. The iced flounder was microbiologically acceptable for up to 7 days with aerobic plate counts reaching <10⁷ cfu/g. The sensory score, determined by the Quality Index Method, linearly increased (r² = 0.96) with the keeping time. All the parameters, including the K‐value, indicated that the shelf life of iced flounder was 7 days.     

MICROBIAL AND SENSORY CHARACTERISTICS OF A FERMENTED SAUSAGE EXTENDED WITH CARBOHYDRATE MATERIALS

Microbial and sensory properties of a fermented sausage, substituted 24% w/w with gelatinized corn starch were studied. The results showed no significant differences in lactic acid bacteria populations between extended samples and the controls, but higher counts of Brochothrix thermosphacta and pseudomonas in extended samples. Results did not indicate any significant differences in odor and flavor, but a difference in texture. A sensory profile diagram of both treatments was obtained, showing the main sensory notes of the products. From the sensory analysis, it was concluded that starch addition up to the levels applied only alter the texture.     

PROCESSING OF YOGURT-BASED PRODUCTS WITH PULSED ELECTRIC FIELDS: MICROBIAL, SENSORY AND PHYSICAL EVALUATIONS

Yogurt-based products similar to a dairy pudding dessert were formulated and processed by mild heat and pulsed electric fields (PEF) to investigate the effects of combined mild heat and PEF treatment on the microbial stability and quality of high viscosity foods. Commercial plain low fat yogurt was mixed with fruit jelly and corn syrup and processed by mild heat treatment at 60C for 30 s and 30 kV/cm electric field strength for 32 μs total treatment time using OSU-2C pilot plant scale PEF system. Control and processed products were aseptically packaged and stored at 4 and 22C. Mild heat combined with PEF treatment significantly decreased the total viable aerobic bacteria and total mold and yeast of yogurt-based products during storage at both 4 and 22C (P ≤ 0.05). Mild heat treatment alone without any PEF treatment did not prevent the growth of microorganisms in yogurt-based products. Sensory evaluation indicated that there was no significant difference between the control and processed products (P ≤ 0.05). Color, pH and °Brix were not significantly affected by mild heat and PEF processing conditions.     

SENSORY, CHEMICAL, AND PHYSICAL CHANGES IN INCREASED WATER ACTIVITY PEANUT BUTTER PRODUCTS

The effects of moisture, temperature, and storage time on the flavor characteristics of increased water activity peanut butter products were determined by sensory analysis. All three factors affected the sensory attributes of the products. At all temperatures and storage times, peanut butter products with 5.0% water added had lower roasted aroma and roasted flavor, with more off-odors and off-flavors than the 2.5% or 0.0% water added samples. Water activity and color were monitored throughout the study, and samples were evaluated for oxidation.     

COLOR, POLYPHENOLOXIDASE, AND SENSORY CHANGES IN BANANA JUICE AS AFFECTED BY HEAT AND ULTRAFILTRATION

A study was conducted to determine the effects of banana maturity (less mature; maturity stage 3, more mature; maturity stage 7), heat treatment of banana puree, heat pasteurization of juice, and ultrafiltration (UF) of juice on color, polyphenoloxidase (PPO) activity, and flavor of puree and juice. Heating puree to 90C inactivated PPO and reduced browning in puree and juice, especially in puree from more mature bananas which had greater PPO activity. PPO activity decreased considerably during cold-setting and filtration of juice, and was not detectable in unheated, pad-filtered juice from less mature bananas. UF of juice through a 10,000 mwco membrance, but not a 30,000, removed all PPO activity and reduced juice browning. Pasteurization of juice (hot fill at 90C) increased browning, but not as much as PPO activity in the puree. Pasteurization had no effect on juice flavor if the puree had been heated to 90C previously as puree, but altered the flavor (i. e., more cooked banana flavor) of juice that had not been previously heated to 90C. Pasteurized juice that had not been heated to 90C as puree had similar flavor (no significant difference) as pasteurized juice that had been heated to 90C as puree.     

SENSORY, NUTRIENT AND CHLOROPHYLL CHANGES IN BROCCOLI FLORETS DURING CONTROLLED ATMOSPHERE STORAGE

Sensory (color, turgor, decay) and nutritional (vitamin C, β-carotene) quality of broccoli florets were evaluated during storage at 4C in air or under a controlled atmosphere containing 2% O₂+ 6% CO₂ (CA). Shelf-life, green color and chlorophyll retention were greater under CA than in air, although loss of stem turgor was accelerated. All samples stored in air had decayed sufficiently by the fourth week to be unfit for consumption, while samples stored under CA showed a few spots of decay after five weeks. However, CA was associated with browning at the cut surface of the stem. Retention of vitamin C was slightly greater in CA than in air, while β-carotene content increased at the end of CA storage. Returning the samples to ambient conditions for 24 h after storage under either conditions resulted in chlorophyll and vitamin C losses, whereas β-carotene content remained stable.