EFFECTS OF DIETARY SUPPLEMENTATION OF VITAMIN E ON FROZEN STORAGE STABILITY OF PRECOOKED BEEF CRUMBLES

Holstein steers supplemented for 122 days with 0, 300 or 1300 IU/day vitamin E (EO, E300, E1300) provided semimembranosus muscle for manufacturing crumbles processed with 1.5% salt and possessing either 10 or 20% fat. They were precooked, packaged (nonvacuum), frozen at -29C and stored at -18C. Following storage for 2, 90 or 180 days, lipid oxidation was measured by TBA and a trained flavor panel. TBA values at 2 days were higher (P < 0.01) for EO than E300 and E1300 crumbles. These values at 180 days for E1300 crumbles were similar to EO and E300 samples at 90 days. Lower TBA values were obtained for 10% vs 20% fat crumbles at 90 days for both E300 and E1300 treatments. Intensity ratings for rancid flavor at 90 days were highest for EO and lowest for E1300 (P < 0.001). Vitamin E exhibited antioxidant properties but additional protection is needed for this product.     

LOW-TEMPERATURE DESTRUCTION OF Trichinella spiralis USING LIQUID NITROGEN AND LIQUID CARBON DIOXIDE

The destruction of Trichinella spiralis by low temperature treatment has been demonstrated to be an effective tool in combatting this parasite in fresh pork products. Current procedures, however, require a holding period under varying times and temperatures to accomplish this destruction. Freezing with cryogenic materials offers the opportunity to attain ultra low temperatures and, thus, eliminate post–freezing holding periods. Four trials were conducted using trichina-infected fresh pork patties approximately 9 mm thick and 88 mm square. In trials 1, 2 and 3 the patties were frozen with LN, using a modified Heath freezing tunnel to final equilibrated temperatures of –12C, –14°C, –20°C, –23°C, –25°C, –28°C, –29°C, –39°C and −47°C. In trial 4 the patties were frozen in a Certified Multideck tunnel using liquid CO₂ as a refrigerant to −10°C, –17°C, –23°C, –29°C and –39°C. Patties were thawed immediately and checked for viable T. spiralis. No positive samples were found at temperatures of –29°C or below.     

QUANTITATIVE STUDIES OF PROTEOLYTIC AND LIPOLYTIC BACTERIA IN FROZEN MINCED BEEF AND HAMBURGER

Sixty frozen samples (30 hamburger patties and 30 minced meat) purchased from different retail markets in Ismailia, Egypt were examined for incidence of proteolytic and lipolytic bacteria. Mean values of proteolytic psychrophiles in the examined samples of hamburger and minced meat were 2×10⁵ and 6×10⁴, respectively. Lipolytic psychrophiles in hamburger were 8×10⁵ and 3×10⁵ in minced meat. Proteolytic mesophiles in hamburger and minced meat were 6×10⁵ and 5×10⁴, respectively. Mean values of lipolytic mesophiles were 5×10⁴ for hamburger and 5×10³ for minced meat. Proteolytic thermophiles in hamburger and minced meat were 3×10³ and 10³, respectively. Both proteolytic and lipolytic activities were exhibited by various bacteria that were identified.     

TIME-TEMPERATURE RELATIONSHIPS FOR IQF SHRIMP WITH LIQUID NITROGEN AND ITS QUALITY ASSESSMENT

Experiments were conducted to study the time temperature relationship during freezing of individual raw shrimp by dipping in Liquid Nitrogen. Four sets of experiments were conducted. The first set involved the assessment of the temperature profile of the gaseous nitrogen environment in a thermocole container with varying quantity of liquid nitrogen. The next two sets of experiments involved direct dipping of the raw shrimp in a liquid nitrogen bath in a thermocole container using perforated stainless steel tray suspended by means of a wire loop, one in a single tier and the other in a double tier. The fourth set was conducted in a laboratory model tunnel provided with immersion freezing facility. In each case, the dipping time was progressively increased from 5 s to 30 s at 5 s increments. The time‐temperature relationships obtained were compared with those from available literature and were found to exhibit similar trend. The quality of the frozen shrimp was also studied in terms of pH, TVB, TMA and Indole content. It was observed that dipping shrimp in liquid nitrogen for the specified period retained the quality well within the acceptable commercial limit.     

ACCEPTABILITY OF VARIOUS GROUND BEEF AND PORK PRODUCTS EXTENDED WITH MECHANICALLY SEPARATED BEEF

Six blends of ground beef and six blends of ground pork containing 0, 15, 30, 45, 60 or 75% mechanically separated beef (MSB) were prepared. Also five batches of fermented sausage and spiced luncheon loaf containing 0, 5, 10, 15 and 20% MSB were formulated. Level of MSB was not related to juiciness rating or mealiness scores of cooked beef/MSB or pork/MSB patties. The level of MSB significantly affected overall eating satisfaction ratings for each blend of MSB patties. MSB at levels of 15% or more had a negative effect on flavor acceptability of cooked ground beef or pork. Fermented sausage products could be extended with only 5% MSB without creating defects in visual appearance or sensory properties. However, the inclusion of 20% MSB yielded a spiced luncheon loaf which was higher in eating quality than an all-beef control. The beef/MSB patties, fermented sausage, and spiced luncheon loaves containing 15% MSB were acceptable for visual appearance. Based on this study, MSB produced from a press type machine, can be blended up to 15% with ground beef, ground pork and sausage products without significantly decreasing raw appearance, sensory properties or storage life. Since MSB is a red meat product available at a similar low cost as textured vegetable protein, the red meat industry would benefit from expanded use of this high protein extender.     

BEHAVIOR OF STAPHYLOCOCCUS AUREUS IN REFRIGERATED AND FROZEN GROUND BEEF AND IN TURKISH STYLE SAUSAGE AND BROTH WITH AND WITHOUT ADDITIVES

Staphylococcus aureus 42E was inoculated into raw ground beef which was stored at 4C and -27C. Turkish style sausage and Brain Heart Infusion broth (BHIB), with and without additives were also inoculated with S. aureus and held at 4C. Samples of ground beef and sausage were examined for S. aureus, aerobic plate count and pH values. The numbers of S. aureus cells were decreased by 1.64 and 2.02 log units in ground beef held at 4C after 7 days and -27C after 7 weeks, respectively. A decrease in the number of S. aureus cells was observed in sausage and BHIB with addition of 0.5% trisodium phosphate (TSP), 78 mg/kg sodium nitrate, 78 mg/kg sodium nitrate plus 156 mg/kg sodium nitrate and 78 mg/kg sodium nitrite plus 0.5% TSP. Overall, sodium nitrite either alone or in combination with sodium nitrate was more effective on S. aureus and aerobic bacteria than TSP either alone or in combination with sodium nitrite.