Effect of Thermal Processing on the Survival of Foot-and-Mouth Disease Virus in Ground Meat

Foot-and-mouth disease virus was examined for its stability during cooking in tissues from infected cattle. The 0₁ (CANEFA 2) serotype of foot-and-mouth disease virus survived in lymph node tissues after heating for 2 hr at 69°C, for 1 hr but not for 2 hr at 82°C, and for 15 min but not for 0.5 hr at 90°C. Incorporation of 1% NaCl into suspensions of infected lymph nodes enhanced viral survival after heating for 0.5 hr but not for 1 hr at 90°C. The virus did not survive in either ground beef or meatballs contaminated with infected lymph node tissue, when processed to internal temperatures of 93.3, 96.1 or 98.8°C using commercial thermal processing procedures. Accurate temperature measurements were achieved with a temperature sensitive indicator disc developed in this study.     

Ingredient Effects on the Thermal Inactivation of Foot-and-Mouth Disease Virus in Formulated, Comminuted Meat Products

The stability of foot-and-mouth disease (FMD) virus after thermal processing of formulated comminuted beef products, such as, Salisbury steak, beef loaf and cured beef prepared from FMD-infected cattle, was examined. Virus survival after product processing in flexible plastic tubes varied with the ingredient present in the product formulation. The virus was completely inactivated in those products containing inorganic salts (sodium chloride, tripolyphosphate or nitrite), farinaceous material or spices after thermal processing to a core temperature of 79.4°C. In those formulated products that contained either FMDV virus-positive milk or heart tissue from infected cattle, the virus survived the above processing conditions. However, the virus was inactivated in these same products after processing to a core temperature of 93°C.     

Studies on the toxicity of phosphine to tolerant stages of Trogoderma granarium Everts (Coleoptera: Dermestidae)

Tests were conducted at 20 and 30°C at 60% r.h. to find the dosages of phosphine needed for control of diapausing larvae and eggs of Trogoderma granarium. At 20°C, 60% r.h., some larvae from each of four recently acquired field strains of T. granarium survived a 5-day exposure period at a concentration-time (Ct) product of 164 g hr/m³. Under these conditions laboratory stock larvae were killed by a 4-day exposure period of about 120 g hr/m³, and eggs by a 3-day exposure of about 50 g hr/m³. Eggs, aged 0–1 days, proved the most tolerant stage at 30°C, 60% r.h., surviving a Ct-product of 16 g hr/m³ over a 2-day exposure period. At 30°C the diapause of larvae became unstable and their tolerance of phosphine was low. Adults emerging after fumigation of larvae appeared normal and if sufficient numbers emerged together a second generation was produced.Complete control of larvae of several stocks (about 20 weeks in diapause) was achieved within a 4-day exposure at 20°C with a mixture of methyl bromide (2.0 g/m³) and phosphine (1.4 g/m³), whereas 6 days were required for these stocks using phosphine alone. To ensure elimination of all stages of non-resistant T. granarium, exposures to phosphine should last 7 days at 20°C and 4 days at 30°C.     

Thermal Properties of Beef Loaf Produced in Foodservice Systems

There is a lack of information on thermal and other properties of foods, especially food mixtures. Physical properties of beef loaf prepared following formula and procedures used in alternate foodservice systems were determined: heat capacity (0.88 cal/g°C uncooked, 0.91 heated to 60°C) moisture content (72.1% uncooked, 66.2% heated), thermal conductivity (0.40 w/cm°C uncooked, 0.47 heated), fat (17.6% uncooked, 13.0% heated) and density (1.00 g/cm³ uncooked and 0.70 heated). The surface heat transfer coefficient for a forced convection oven was also determined (62 w/ m²°C.) Times to heat beef loaves to specified ending temperatures in a forced convection oven at 163°C and 176°C were calculated. There was less than 1 min difference in calculated heating time required to reach the desired end temperature. The actual times to reach ending temperature show very good agreement with the calculated times.     

Evaluation of 54° and 60°C Holding Temperatures on Aerobic Plate Counts and Coliform Determinations of Control and Post Cooking Contaminated Beef Roast

Fabricated beef roasts were cooked to an internal temperature of 60°C and the surface inoculated with a suspension of Escherichia coli at a level of lo⁶ cells/cm². Roasts were then stored in a warming oven at 54° and 60°C for 1, 2, 6, and 12 hr. Under these conditions the destruction of this strain of E. coli is quite rapid (less than 6 hr) at the 60°C holding temperature. The holding temperatures do allow the growth of thermoduric organisms naturally present in the product to initiate exponential growth after 6 hr at 54°C. The higher holding temperature reduced the rate of multiplication of the thermoduric organisms.     

Preconcentration of Apple Juice by Reverse Osmosis

Single strength apple juices (10° Brix) were processed by reverse osmosis to 20-25°Brix, primarily at 20°C. A pilot scale plate and frame UF-RO system equipped with cellulose acetate (CA) membranes, CA-865 and/or CA-990, or high resistance (HR) membranes, HR-95 and/or HR-98, was operated at pressures of 35-45 bar. At 45 bar, the larger pore-sized CA-865 possessed the highest processing capacity of 26.9 L/m²/hr (from 10°Brix to 20°Brix) and concentration limits of 35° Brix, but had low recovery of solutes and flavor volatiles. The HR-95 and HR-98 had similar processing capacities of 15-16 L/m²/hr and concentration limits of 20-25° Brix at 45 bar. The recoveries of 97% solutes and 87% apple flavor volatiles were obtained using either the HR-95 or the HR-98.     

Packaging Film Permeability in Conjunction with Sodium Nitrite, Potassium Sorbate or Lactic Acid Starter Culture for Control of Clostridium sporogenes (PA3679) Growth in Sliced Bologna

A sliced bologna was prepared and inoculated with Clostridium sporogenes (PA3679), packaged in films ranging in oxygen permeability from 0.1 cc/m²/24 hr to 120 cc/m²/24 hr and stored at 5°C, 15°C or 25°C. Subsequent bologna preparations included either 156 ppm sodium nitrite, 0.26% potassium sorbate or a lactic acid starter culture. Water activity, pH, TBA number and PA3679 counts were monitored during 28 days of storage. TBA numbers increased in packages with over 60 cc/m²/24 hr permeability but PA3679 counts did not change as a function of packaging film. Nitrite and sorbate were equally effective as inhibitors. At 15°C and 25°C, the lactic acid culture allowed the least PA3679 growth. Oxygen permeability did not alter any inhibitory effects even when increased TBA numbers resulted from using an oxygen-permeable film.     

Apple Quality as Influenced by Fumigation with Methyl Bromide

The use of methyl bromide (MeBr) did not detract from the firmness or skin color of‘Delicious’, ‘Golden Delicious’ or ‘Granny Smith’ apples. Fruit fumigation with MeBr resulted in a darkening of the objective and subjective internal flesh color of ‘Delicious apples, particularly unwaxed apples treated with 48g MeBr/m₃ at 20°C for 2 hr. Internal flesh color of ‘Golden Delicious’ apples was not influenced at 48g MeBr/m³ at 6°C for 2 hr. Fumigation with 32g MeBr/ m³ at 20°C or 56g MeBr/m³ at 6°C for 2 hr did not detract from the firmness or internal color quality of ‘Delicious’, ‘Golden Delicious’ or ‘Granny Smith’ apples after 60 days in storage. MeBr-treated apples displayed greater acidity and less ethylene production than control fruit. Higher MeBr treatment temperature and the use of wax on fruit directly influenced the reaction of apples to MeBr fumigation.     

Moisture Transfer Properties of Dry and Semimoist Foods

Equilibrium moisture content, mass diffusion coefficients, and densities were collected for wheat flour, shredded wheat, raisins, nonfat dry milk, and freeze-dried apple, turnip, and ground beef at 25 ± 1°C. Flour adsorbing to 0.75 a_w had the largest mass diffusion co-efficient, 1.15 × 10^?7 m²/hr and raisins had the smallest value of 0.015 × 10-⁷ m²/hr. Two of the food uroducts. flour desorbing to 0.11 a_w, and the freeze-dried turnip, exhibited diffusion coeffcients which were dependent on the moisture content. Most of the foods reached equilibrium within 1 wk based on an objective criterion of no more than a 0.5% dry basis moisture difference over three successive readings at 1 wk interval.     

Thermophysical Properties of Extruded Beef/Corn Flour Blends

Thermal properties, specific heat, and thermal conductivity of three beef/corn meal blends extruded to reach end product temperatures of = 91°C and 109°C were analyzed. Density was also measured and used to calculate thermal diffusivity. The extruded products had densities of 1,054 to 1,091 kg/m³; specific heat was 2.944 to 3.055 kJ/ kgK; and thermal conductivity, 0.26 to 0.39 W/mK. Calculated values of thermal diffusivity were 0.831 to 1.200 (xl0^-7m7sec). With the exception of specific heat, extrusion conditions and formulation affected some of the products physical characteristics and thermal properties.     

The Effects of a Beef‐Based Meal Compared to a Calorie Matched Bean‐Based Meal on Appetite and Food Intake

Protein and fiber have strong satiety‐inducing potential. Beef is a high quality, protein‐rich food. Beans contain moderate levels of protein as well as fiber. To determine the effects of a high protein meal (beef) compared to a moderate protein, high fiber meal (beans) on subjective appetite and energy intake at a subsequent meal twenty‐eight adults, 14 men (ages 24 ± 5 y, BMI 23 ± 2 kg/m²) and 14 women (ages 25 ± 5 y, BMI 22 ± 2 kg/m²) consumed 2 test lunches containing a “meatloaf” made from either beef or beans. The beef meal provided 26 g of protein and 3 g of fiber while the bean meal provided 17 g of protein and 12 g of fiber. An ad libitum snack was given 3 h after the test meal. Visual analogue scales were used to assess hunger, satiety, fullness, and prospective food intake. Gastrointestinal (GI) tolerance was assessed over 24 h. No difference between the beef and bean was observed for appetite ratings over 3 h, food intake at the subsequent meal (632 ± 75 kcal compared with 611 ± 75 kcal, respectively), or sum of GI score (2.2 ± 0.5 compared with 2.9 ± 0.5, respectively). Gas and bloating were reported more often after the bean meal than the beef meal (2.0 ± 0.4 compared with 1.3 ± 0.4, P value 0.057). A beef‐based meal with high protein and a bean‐based meal with moderate protein and high fiber produced similar satiety, while the bean‐based meal resulting in higher, yet moderate, gas and bloating.     

Consumption of oxygen by the muscles of beef animals and related species and its effect on the colour of meat. I. Oxygen consumption in pre-rigor muscle

The oxygen consumption rate (o.c.r.) of pre-rigor beef muscle has been studied in relation to temperature and to the rates of ATP-turnover (a.t.r.) and of mitochondrial oxidation (m.r.). The o.c.r. of strips of muscle has a constant enthalpy of activation (Δ H*) of 10–11 kcal/mol (Q¹⁰ °C = 1.8) over the range of 2–38 °C. From 15–38 °C, the rate-determining reaction is the resting turnover of ATP (a.t.r.) due to slow, undefined ATP-hydrolases, which have an identical ΔH* value of about 10.5 kcal/mol. Below 11 °C, the phenomenon of cold-shortening sets in, due to partial activation of the “contractile” myofibrillar ATPase as the temperature is lowered, with the result that the a.t.r. passes through a minimum at 5 °C, and at 1 °C has become as high as at 15 °C. Under these conditions the a.t.r. is too high for mitochondrial respiration to cope with the ADP produced, so that the m.r. increasingly becomes rate-limiting. The o.c.r. and a.t.r. of pre-rigor muscle are both increased by damage, strips showing rates about 2 times and minces about 4 times those given by intact tissue. The r.q. of beef muscle is 1, the substrate almost certainly being the pyruvate derived from glycolysis. The P:O ratio, derived from the observed a.t.r. and o.c.r., has a mean value of 2.8 in beef muscle and of about 2.3 in the muscles of the rabbit, sheep and pigeon. The latter is significantly lower than the theoretical ratio of 3.08.     

The influence of temperature on the susceptibility to eight organophosphorus insecticides of susceptible and resistant strains of Tribolium castaneum,Oryzaephilus surinamensis and Sitophilus granarius

Susceptible strains of adult Tribolium castaneum, Oryzaephilus surinamensis and Sitophilus granarius were exposed for 24 hr to a range of deposits (from 10 to 5000 mg/m²) of eight organophosphorus insecticides (bromophos, chlorphyrifos-methyl, fenitrothion, jodfenphos, malathion, phoxim, pirimiphos-methyl and tetrachlorvinphos) at 10, 17.5 and 25°C. Based upon knockdown and kill, the effectiveness of all insecticides was greater at 25°C than at 17.5°C and was markedly lower at 10°C. At 10°C tetrachlorvinphos, bromophos and jodfenphos were virtually ineffective to S. granarius even at 5000 mg/m². By contrast at 25°C, 100 mg/m² was adequate to give complete knockdown of all species with most insecticides, the exceptions being malathion and tetrachlorvinphos. The three most effective insecticides, chlorphyrifos-methyl, pirimiphos-methyl and fenitrothion were also tested, in comparison with malathion, against a known malathion-resistant strain of each of the test species. Chlorpyrifos-methyl and pirimiphos-methyl were the most effective materials against both susceptible and resistant strains of all species. Knockdown was inevitably followed by mortality although at the lower temperatures this took several days.     

DETERMINATION OF FLUID-TO-PARTICLE HEAT TRANSFER COEFFICIENTS FOR ROTATING PARTICLES1

Fluid-to-particle heat transfer coefficients (h_fp) were determined for stationary and rotating potato-alginate cubes heated by carboxymethylcellulose solutions in an aseptic processing system. Fluid temperature, fluid average velocity, CMC concentration, and particle size were varied. In the stationary particle case, the slip generalized Reynolds numbers (Re_gs) ranged from 1.3 to 6.7. For the rotating particles, Re_gs ranged from 0.91 to 5.0 and the generalized rotational Reynolds numbers (Re_gr) ranged from 6.0 to 33. The h_fp ranged from 120 W/m²°C to 2400 W/m²°C and from 360 W/m²°C to 4300 W/m²°C for stationary and rotating particles, respectively. Particle rotation significantly increased h_fp. Fluid temperature, particle size, fluid average velocity, and CMC concentration had significant effects on h_fp for both stationary and rotating particles. Using Re_gs in the dimensionless correlation gave a better prediction of h_fp for the rotating particles than using Re_gr.     

Thermal transition and thermo-physical properties of potato (<Emphasis Type="Italic">Solanum tuberosum L</Emphasis>.) var. Russet brown

Potatoes are an important food in many regions of the world and are commonly used in a variety of food products. Thermal transition and thermo-physical properties of potatoes are important in order to design efficient food processes and select appropriate storage conditions. In this study, we determined the thermal transitions and thermophysical properties of raw and blanched/par-fried potato for a temperature range of ??32 to 21.1 °C. Using differential scanning calorimetry, we found an initial freezing point (T_f) at ??1.8?±?0.1 °C, an onset of melting (T_m^′) at ??9.9?±?0.2 °C and an unfreezable water content (X^′_w) for maximally freeze-concentrated raw potato at 0.21 kg water/kg potato. Corresponding values for blanched/par-fried potatoes were ??0.9?±?0.1 °C, ??11.0?±?0.2 °C and 0.18 kg water/kg potato. Results show that an increase in solids content decreased T_f of both raw and blanched potatoes. We modelled the relationship between them using the Chen model. The apparent specific heat (C_app) increased around T_f to 31.7?±?1.13 kJ/kg K for raw potato and 26.7?±?0.62 kJ/kg K for blanched/par-fried potato. For frozen raw potato at ??32 °C, thermal diffusivity (α) was 0.89?±?0.01?×?10?^?6 m²/s and thermal conductivity (k), 1.82?±?0.14 W/m K, respectively. These values were higher for frozen raw potato than for the unfrozen raw potato (0.15?±?0.01?×?10?^?6 m²/s and 0.56?±?0.08 W/m K, respectively at 21.1 °C). The apparent density (ρ) of frozen raw potato (992?±?4.00 kg/m³ at ??32 °C) was less than that for unfrozen raw potato (1053?±?4.00 kg/m³ at 21.1 °C), and a similar trend was obtained for blanched/par-fried potato (993?±?2.00 kg/m³ at ??32 °C and 1188?±?7.00 kg/m³ at 21.1 °C, respectively). This study established a correlation between thermo-physical properties and temperature. Findings may be used to inform the design and optimization of freezing processes and frozen storage for potato products.     

Hyperfiltration of Tomato Juice during Long Term High Temperature Testing

A tubular hyperfiltration membrane system was studied with tomato juice in a recirculation mode. Two aromatic polyamide thin film composite membranes (ZF 99) (1.3 m²) were examined. After 52 hr of operation with tomato juice one membrane exhibited a flux of 39.7 Lm^?2hr^?1 (72°C, 55.2 bar). Another membrane, after 717 hr, gave a flux of 41 Lm^?2hr^?1 (78°C, 41.4 bar) and natural tomato soluble solids (NTSS) rejection of 94 to >98%.     

Virucidal Effectiveness of Flexible Pouch Processing of Meat Products Prepared from Foot-and-Mouth Disease-Affected Cattle

Thermal processing of ground beef, beef cubes or beef slices in commercially popular flexible pouches, effectively inactivated foot-and-mouth disease (FMD) virus that had resulted from infection of cattle. Cooking the meat products at 75°C for 20 min or 80°C for 15 min was virucidal; however, FMD virus survived in ground beef products processed for shorter time periods and/or at lower temperatures. The processing schema described were limited to 200g samples of these meat products. Postmortem decrease of pH due to electrical stimulation of carcasses inactivated the virus in skeletal muscle but not in lymph mode tissue.     

Improved Tenderness of Restructured Beef Steaks by a Microbial Collagenase Derived from Vibrio B-30

To reduce connective tissue toughness Vibrio B-30 collagenase was evaluated for its ability to degrade muscle collagen in a restructured beef (RSB) product. Dissected muscles pooled from clods of 4 USDA choice chucks were made into three RSB products: untrimmed control (C), hand trimmed of epimysium (T) and untrimmed and treated with 0.01% collagenase (E). RSB products were held for 24 hr at either 2°C or 11°C and were analyzed cither raw or after heating (40°C for 1 hr). Aerobic microbial load remained low (1–2X10² cfu/g) during the 24 hr 11°C incubation. Heated samples of enzyme treated RSB had lower Lee-Kramer shear values than controls. In both raw and heated samples enzyme treatment increased hydroxyproline solubility. An enzyme treatment of 24 hr at 11°C followed by heating produced maximum tenderization. Although optimum treatment conditions need to be defined by further research, Vibrio B-30 collagenase appeared to be efficacious for the tenderization of RSB products.     

Microbiology of a Ham-Type Product Made from Soy-Extended Cured Beef and Inoculated with Clostridium sporogenes PA3679

The microbiological stability of a new ham-type product made from soy-extended cured beef was examined under wholesale (2–4°C) and retail (5°C) refrigerated storage conditions, and during abuse-temperature holding for 24 and 48 hr at 24-25°C after inoculation with Closrridium sporogenes PA3679. No microbiological effects (P >0.05) could be attributed to the level of soy protein isolate in the injection brine (0, 5, 7.5 or 9%) on the basis of mesophilic, psychrotrophic, anaerobic and lactic bacterial counts. Samples held at 2-4°C did not exceed 10⁴ CFU/g after 4 wk for any bacterial type examined. Product shelf-life was > 3 wk at 5°C and 2 wk at 8–10°C. Inoculated PA3679 did not grow in the product during 24 or 48 hr simulated mishandling (24-2°C).     

Effect of temperature and bulk density on thermal conductivity of spray-dried whole milk powder

The thermal conductivity of whole milk powder was determined by a steady-state guarded hot-plate method at temperatures ranging from 11·8 to 43·2°C, at bulk densities 0·512 and 0·605 g cm^?3.It was found that thermal conductivity increased with increasing temperature and with increasing bulk density. Thermal conductivity increased from 0·036 W m^?1 K^?1 at 11·8°C to 0·077 W m^?1 K^?1 at 43·2°C for bulk density 0·512 g cm^?3, while for bulk density 0·605 g cm^?3 thermal conductivity increased from 0·058 W m^?1 K^?1 at 16·6°C to 0·093 W m^?1 K^?1 at 42·8°C.