Evaluating the ability to measure pork fat quality for the production of commercial bacon.

This study was conducted to evaluate three fat quality measures to characterize the suitability of pork bellies for commercial bacon production. Bellies from six sources (A to F) and two weight ranges (4.5/5.5 kg and 5.5/6.4 kg) were sampled by randomly selecting 50 belly sets from commercial combos of pork bellies from each source. The fat on these 50 individual bellies was assessed for quality using three methods: an FTNIR spectrophotometer to predict iodine (IV) value, a Durometer to assess fat firmness, and a subjective fat quality score (FQS) to assess integrated values of fat color, firmness, oiliness, and wetness. Data show that the fat quality measures differed (P<0.05) by pork belly source and weight class with significant interactions between the two. Bellies were subsequently manufactured into bacon and bacon slicing yield index varied significantly (P<0.05) by belly source, weight class, and their interaction. Durometer and FQS results were significantly (P<0.05) correlated with bacon slice yield. The 50 belly subsamples obtained from each source/weight class also allowed the prediction of frequency distribution-based values based on fat quality measures (proportion IV>74, proportion Durometer value <50, and proportion FQS>3. These were also correlated with slice yield. The data lead to a new paradigm model that is useful to describe both the uncertainty in fat quality measures and the relationships observed from pork bellies from different sources.

Inhibition of Listeria monocytogenes growth in cured ready-to-eat meat products by use of sodium benzoate and sodium diacetate.

The effect of sodium benzoate (0.08 to 0.25%) in combination with different concentrations of sodium diacetate (0.05 to 0.15%) and NaClI (0.8 to 2%) and different finished product moisture (55 to 75%) on the growth of Listeria monocytogenes in ready-to-eat meat products was evaluated using a central composite design over 18 weeks of storage at 4 degrees C. The effects of these factors on time to growth were analyzed using a time-to-failure regression method. All main effects were significant except product moisture, which was significant when included in the two- and three-way interactions (P < 0.05). Sodium benzoate was more effective (lengthening time to growth) when used with increasing concentrations of sodium diacetate and salt and decreasing finished product moisture. The model indicated that low-moisture products, e.g., bologna or wieners, could have time-to-growth values longer than 18 weeks if they were formulated with 0.1% sodium benzoate and 0.1% sodium diacetate. Time to growth in high-moisture products, e.g., ham or cured turkey breast at 75% moisture, was predicted to be much shorter for the same basic formulation (0.1% sodium benzoate and 0.1% sodium diacetate). Consequently, high-moisture ready-to-eat products in which sodium benzoate is limited to 0.1% (current standard for generally recognized as safe) may need additional ingredients to effectively inhibit growth of L. monocytogenes.

Modeling the growth boundary of Listeria monocytogenes in ready-to-eat cooked meat products as a function of the product salt, moisture, potassium lactate, and sodium diacetate concentrations.

A central composite response surface design was used to determine the time to growth of Listeria monocytogenes as a function of four continuous variables: added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (60% [wt/wt]; 0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) in ready-to-eat cured meat products. The design was repeated for ready-to-eat uncured meat products giving a fifth categorical variable for cure status. Products were stored at 4 degrees C. The results were modeled using a generalized regression approach. All five main effects, six two-factor interactions, and two quadratic terms were statistically significant. The model was used to show the boundary between growth and no-growth conditions at 4 degrees C using contour plots of time to growth. It was validated using independent challenge studies of cured and uncured products. Generally, the model predicted well, particularly for cured products, where it will be useful for establishing conditions that prevent the growth of L. monocytogenes. For uncured products, there was good agreement overall between predicted and observed times to growth, but the model is less thoroughly validated than for cured products. The model should initially only be used for screening of formulations likely to prevent growth of Listeria monocytogenes in uncured products, with recommendations subject to confirmation by challenge studies.

Modeling the growth of Listeria monocytogenes in cured ready-to-eat processed meat products by manipulation of sodium chloride, sodium diacetate, potassium lactate, and product moisture content.

A central composite second-order response surface design was employed to determine the influences of added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) on the predicted growth rate of Listeria monocytogenes in cured ready-to-eat (RTE) meat products. Increased amounts of both sodium diacetate (P < 0.11) and potassium lactate (P < 0.001) resulted in significant reductions in the growth rate constants of L monocytogenes. Increased finished-product moisture (P < 0.11) significantly increased growth rate constants. The nfluence of sodium chloride was not statistically significant. The second-order statistical factor for lactate was significant (P < 0.01), but all two-way interactions were not. In general, predicted growth rates exceeded actual growth rates obtained from inoculation studies of four cured RTE meat products (wieners, smoked-cooked ham, light bologna, and cotto salami). The final model will be useful to food technologists in determining formulations that will result in finished cured RTE meat products in which L. monocytogenes is not likely to grow.

Seasonal variation in venison quality of mature, farmed red deer stags in New Zealand.

Two studies involving 20 red deer (Cervus elaphus) stags were conducted to determine the effects of season on venison quality. In each study, five sexually mature red deer stags were slaughtered immediately preceding the rut (autumn) and five were slaughtered after the rut. Stags slaughtered postrut had lower carcass weights (25 to 30%) than those slaughtered prerut. Average bodywall thickness measurements above the 12th rib (an indicator of fat thickness) were approximately 31 mm prerut compared with 3 to 7 mm postrut. Individual muscles and retail cuts (which included subcutaneous and intermuscular fat) were heavier in prerut carcasses. There were significant decreases in intramuscular fat in both the longissimus muscle and the semimembranosus muscle. Postrut longissimus muscle steaks appeared brighter and(or) fresher than the other groups; color acceptability was negatively correlated (P less than .05) with fat content. Prerut streaks from both muscles were more tender than postrut steaks from those muscles. Overall desirability and tenderness were highly correlated (r = .94 and .82 for longissimus muscle and semimembranosus muscle, respectively).

Influence of packaging method and length of chilled storage on microflora, tenderness and colour stability of venison loins.

Sections of venison loins (LD) weighing approximately 300 g from 12 red deer (Cervus elaphus) were packaged using four packaging methods: (a) vacuum packaging, (b) CO(2) flushed using a nylon containment film (CO(2)-Nylon), (c) CO(2) flushed using an ultra-high barrier containment film (CO(2)-UHB), and (d) CO(2) flushed using an aluminium foil laminate containment film (CO(2)-Foil) and stored for 1, 6, 12 and 18 weeks at 0°C. Meat pH values were lower in all CO(2) flushed meat packages (P<0·05) than in vacuum packaged meat. Lactic acid bacteria and total anaerobic counts increased over storage time in all packages regardless of treatment up to values of log(10) 7·8 and 7·6 g(-1), respectively. Tenderness tended to increase as meat was stored for up to 18 weeks. Colour scores taken during simulated retail display indicated that colour deteriorated more rapidly when meat was stored for 12 and 18 weeks than for 1 and 6 weeks. Vacuum packaging and gas flushing (CO(2)-Foil) resulted in higher initial colour scores than venison packaged in the CO(2)-Nylon or CO(2)-UHB materials. Venison stored for 18 weeks also exhibited a higher proportion of packages containing off odours, lower flavour desirability and flavour intensity scores as well as higher off flavour scores than meat stored for shorter times. The implications of these effects are discussed. Although there were few significant differences in microbial growth and sensory characteristics due to packaging method or containment film, vacuum packaging appeared to be the most economic and produced meat of better colour stability.