SUMMARY— A method was developed to objectively measure the emulsifying capacity (ECJ of meat and fish protein extracts by electrical resistance. The method of Swift et al. (1967) was modified to deliver oil at a constinuous rate at the point of blender agitation, thus forming an emulsion for testing the validity of the electrical resistance method. This modification reduced the variance of the end‐point determination within samples. The precision of end‐point determinations by electrical resistance was equivalent to the modified visual method, and had the advantages of being objective, having a finite end‐point and providing a continuous record of the emulsion during formation and collapse. The EC of fresh muscle slurry extracts from fish were higher than those from beef and pork. However, the EC of fresh muscle supernatant extracts ranked from highest to lowest are beef, fish and pork, respectively. In all cases, the EC of supernatant and fresh muscle extracts was higher than the slurry and frozen muscle extracts, respectively.

Fresh poultry breasts were dipped in a solution containing either 0, 2.5, 5.0 or 10.0% potassium sorbate for 1 min. Another lot of fresh poultry breasts was dipped in a suspension of either 103 or 105 cells of three strains of Salmonella/ml before being dipped in one of the potassium sorbate solutions. Use of a potassium sorbate dip significantly reduced the total number of viable bacteria on the poultry parts when compared to the untreated control parts after 7 days of storage at 10 C and after 8 days at 6 C. Use of a 10.0% sorbate dip significantly reduced the total plate count as related to the total plate count of the control parts after 5 days of storage at 22 C. Application of a 10.0% sorbate dip resulted in a significantly lower Salmonella count than of the untreated parts after 7 days of storage at 10 C and a 5.0% or greater sorbate dip markedly reduced the growth rate of the Salmonella at 10 and 22 C when compared to the growth rate of the Salmonella on control parts.

Experiments to determine the effect of sorbic acid alone and in combination with low nitrite and phosphate on botulinal toxin production in inoculated perishable, canned, cornminuted, cured pork were conducted. Forty-eight test lots of product were inoculated with approximately 100 spores per gram of five strains each of type A and B Clostridium botulinum. Twenty-five cans of each test lot were incubated at 27°C for up to 110 days. The time of swelling was recorded for each can and the first 10 swells per test lot were tested for toxin. Multiple regression analysis of the time to first swell showed nitrite concentration had a significant linear effect on delaying outgrowth and toxin production of C. botulinum. Sorbic acid concentration was also significantly related to inhibition but through the fourth power of sorbic acid concentration. The use of either sodium acid pyrophosphate or sodium hexametaphosphate was synergistic with sorbic acid as indicated by their statistically significant positive interactions. Several test lots containing 0.2% sorbic acid and either phosphate had no toxic swells after 110 days of incubation with or without 50 ppm NaNO,. These data indicate that sorbic acid may be a potential alternative preservative to high levels of nitrite in canned, comminuted pork products.

In an effort to reduce the initial levels of nitrite used to cure bacon and still supply the botulinal inhibition expected in cured meats, bacon was produced at nitrite levels of 0 and 40 ppm NaNO2 with and without 0.13 and 0.26% potassium sorbate. This bacon was inoculated with 1100 spores per g of a mixture of five Type A and five Type B strains of Clostridium botulinum. The time for occurrence of the first swollen package and number of toxic swells were recorded over 110 days of incubation at 27 C. The above variables were compared to bacon containing 80 and 120 ppm NaNO2 as well as a commercial sample. Presence of potassium sorbate in the cure significantly reduced the number of toxic swollen packages occurring during incubation and lengthened the time before a toxic swollen package was observed. The presence or absence of 40 ppm NaNO2 appeared to have no significant effect on the sorbate inhibition of C. botulinum in bacon in this study. Microbial growth of uninoculated samples was also retarded by addition of potassium sorbate to the brine. Flavor panel evaluations indicated that potassium sorbate decreased preference slightly using experienced judges. Also, reduced occurrence of nitrosopyrrolidine with reduced nitrite was observed.

A laboratory technique for the preparation of small batches of sausage emulsion was developed for a comparative study of the effectiveness of fresh and frozen beef in achieving emulsion stability.The technique consisted of three basic steps: (I) low speed chopping and blending of ingredients at -2" to +20c; (2) low speed blending with the gradual addition of soybean oil at 2" -8°C; and (3) high speed chopping to a temperature of 15"16°C.The preparation and evaluation of emulsions with widely varying compositions revealed that the lean and fat percentages could be varied over wide ranges without significantly affecting emulsion stability, but the range for percentage of water was narrow and critical to stability.The relative stability for fresh and frozen lean was influenced by the amount of added water. For example, at 30% fat level, there was a sharp drop in stability as the added water was reduced below 16% for fresh beef; whereas, an equivalent drop in stability was found as the added water was reduced below 21% for frozen beef. The theory is proposed that emulsion instability is highly dependent upon the level of added water based on results of this investigation.