coli O157:H7 in dry fermented sausages

Dry fermented sausages (DFS) have been subject to numerous validation studies, as pathogen reduction heavily relies on both ingredients and processing. In this study the effect of product caliber size (32, 55, 80mm), and fat level (low, 9.67%; high, 18.46% wt/wt) on the inactivation of E. coli O157:H7 during DFS production was examined. Sausages containing a five-strain cocktail of E. coli O157:H7 at 10⁷CFU/g were manufactured and monitored for changes in physicochemical properties and inoculated E. coli O157:H7 numbers were enumerated during the DFS production stages and log reduction rates were calculated. Significant (P<0.01) reduction in pH from 5.9 to 4.9 was observed in all sausages within 72h of fermentation; however, the observed pH reduction was not significantly (P>0.05) different among sausages of different caliber size or fat levels. No significant (P>0.05) reduction in a_w was observed during fermentation of the sausages. However, during the drying phase, sausages with larger caliber sizes required a significantly longer duration of drying to achieve the same a_w of smaller caliber size sausages. For instance, to achieve an a_w of ≤0.9, following 5days of fermentation/curing, 80mm caliber sausages required up to 27days of drying compared with 13 and 6days for 55 and 32mm caliber size sausages, respectively. Fat levels on the other hand did not significantly (P>0.05) effect the reduction of a_w during drying of the sausages. During the fermentation stage there was a significant and rapid reduction in E. coli O157:H7 counts by about 1.1- to 1.4-log units, but was not significantly different among sausages of different caliber size and fat levels. Considering the whole process, only caliber size had a significant effect on log reduction of E. coli O157:H7. ANOVA of log reduction rates of E. coli O157:H7 among sausages of different caliber size and fat levels revealed no significant differences during the fermentation, however, during the drying of the sausages, log reduction rate of E. coli O157:H7 was significantly (P<0.01) lower in sausages with larger caliber sizes and higher fat levels. For instance, log reduction rates for E. coli O157:H7 in high fat large caliber sausages was the lowest at -0.082±0.004 log CFU/g/day compared to all other fat and caliber size combinations. These results suggest that DFS manufacturers producing higher fat and large caliber size products need to consider longer drying periods to achieve the required 5-log inactivation of E. coli O157:H7.

Optimization of compositional and structural properties in probiotic sausage production

In this study, the effects of different fat levels and different particle sizes on compositional and structural characteristics of probiotic fermented sausage were investigated. In order to obtain probiotic character, Lactobacillus casei CRL431 was added. The physicochemical, microbiological and sensory analysis were done. The effect of fat level x mincer hole diameter interaction on hardness values were statistically significant (p < 0.005). At the end of the fermentation-ripening period, L.casei CRL-431 count has reached to sufficient microbial count (10(6) cfu/g of probiotic bacteria) to demonstrate the character of probiotic food. A significant positive correlation was found between L.casei CRL431 count and surface appearance, texture and overall acceptability scores (r = 0.60, 0.52, 0.53). The values of TBARS number of probiotic sucuk samples increased during fermentation-ripening. A significant correlation between taste-aroma scores and fat level was detected (r = -0.61,p = 0.0008). Consiquently, the best sensorial quality was determined in L3 samples and the worst sensorial quality was determined in H8 samples.

Sensory evaluation of tender beef strip loin steaks of varying marbling levels and quality treatments

The palatability of tender [Warner-Bratzler shear force values <33.34N (3.4kg)] beef strip loins of 10 different treatments [USDA Prime, High Choice (upper 1/3 Choice), Low Choice (lower 1/3 Choice), Select, Standard, Australian Wagyu, American Wagyu, Holstein Select, Holstein Top Choice (upper 2/3 Choice) and Grass-finished] was evaluated by consumers and a trained flavor panel. In general, tenderness, juiciness, flavor, and overall liking ratings as well as acceptability percentage for each trait, increased with increased fat levels. Moreover, overall liking was highly correlated (P<0.01) with flavor liking (r=0.96) as well as fat percentage (r=0.79). Beef flavor scores were positively associated (P<0.01) with fat-like (r=0.67) and umami (r=0.59) flavors. Fat level was the primary driver of beef flavor acceptability in all samples when no undesirable off-flavors were present.

Effect of different fat level on microwave cooking properties of goat meat patties

The study was carried out to evaluate the effect of various fat levels on the cooking and sensory properties of goat meat patties cooked by microwave energy. Goat meat patties were prepared with refined vegetable oil to get fat level of 5, 10, 15 and 20%. Each patty was cooked in a microwave oven with full power (700 W) operating at 2450 MHz to an internal temperature of 75-80 °C. pH value of raw patties with 5% fat level were lower compared to patties with 10, 15 and 20% fat level. Fat level did not affect emulsion stability of batter but it decreased as fat level increased. Microwave cooking time decreased as fat levels increased. With an increase in fat contents, protein and moisture in raw patties decreased and in cooked meat patties with 5% fat had higher protein and moisture content than those with more fat. Patties with 5% level showed lower cooking loss than other fat level. Water activity of patties was affected by fat level and patties with 15 and 20% fat had lower water activity than patties with 5 and 10% fat. As fat level increased, shear force value decreased indicating soft texture. Subjective colour evaluation indicated that 5% patties were darker and redder than patties with more fat. Sensory analysis revealed that goat meat patties with 5 and 10% fat had less flavour and juicer than patties with 15 and 20% fat. Goat meat patties with 20% fat were the juiciest. Tenderness and oiliness increased significantly with an increase in fat level. Patties with 15% fat were rated higher overall palatability than others.

Effect of fat level on physicochemical, volatile compounds and sensory characteristics of dry-ripened "chorizo" from Celta pig breed

A traditional Spanish dry-ripened sausage "chorizo" from Celta pig breed was formulated with 10, 20 and 30% of back fat (LF, MF and HF, respectively). An increase in fat content significantly affected the chemical composition of the sausages at the end of ripening (higher fat content and lower protein content and moisture) and physico-chemical parameters (lower pH, aw, hardness, springiness and chewiness and higher TBARS index, L*, a* and b* values). With the increase of fat in the sausage formulation a higher total content of free fatty acids (FFA) was also obtained, showing a greater lipolysis than in LF sausages. All these parameters were significantly affected by ripening time. A lower total content of volatile compounds were found in HF sausages, being detected 3 alcohols, 4 aldehydes, 12 esters, 3 ketones, 7 aliphatic and 4 aromatic hydrocarbons. Sensorial analysis showed differences for fat level and fat-lean cohesiveness within appearance attributes; odour intensity and spices odour within odour attributes and hardness within texture attributes.