Research Accomplishment Reports 2009

Development of Peptides to Enhance Cheese Production and Bio-active Probes

C.L. Hicks
Department of Animal and Food Sciences

 

Non-Technical Summary

Bacteriophage (virus) often interfere with the cheese making process. The purpose of this project is to develop peptides that block the receptors on host cells to inhibit phage proliferation.

2009 Project Description

Results from this project have been disseminated to stakeholders through two primary avenues. The first is through scientific publications (there was one presentation that generated an abstract). Secondly, results have been presented at national meeting to interested parties. In this case we have presented results of our findings at the annual meeting of the Institute of Food Technologist in July 2008 where attendees from both industry and academia were present. This research was also showcased internationally in conferences in Indonesia in 2009.

2009 Impact

A method to prevent the settling of bacterial cells was explored so that accurate optical density (OD) measurements could be determined throughout the log and stationary phases of cell growth. Earlier experiments had shown that agitation only provided temporary dispersal of settled cells but appeared to enhance cell agglutination, size of cell complexes, and speed of settling after agitation. Thus, hydrocolloids were added to trypic soy broth (TSB) to enhance medium viscosity to inhibit cell settling problems that frequently occur when growing Escherichia coli. Xanthan, Kappa Carrageenan, Kappa/Lambda Carrageenan, Guar, Sodium Carboxymethyl Cellulose, and Sodium Alginate were tested. Loss of viscosity upon autoclaving, ease of solubility, and change in translucency were problems encountered with some hydrocolloids. However, none of these problems were encountered with Sodium Alginate, thus all further research was conducted with sodium alginate. Concentrations ranging 0.8 to 1.5% of Sodium Alginate were tested in TSB with E. coli strain B (ATTC 11303) as the growth organism at 37° C. Apparent viscosities of all solutions were measured using a Brookfield viscometer. The optimal level of Sodium Alginate added to the growth medium was determined to be between 1.0 to 1.1%. Levels below or above this range did not prevent cell settlement. Growth curves of E. coli, as measured by OD, in TSB broth containing 1.0 to 1.1% Sodium Alginate were very uniform and final OD readings were approximately 30% greater than when cell settling occurred. TSB assays modified in this manner will more accurately enumerate E. coli cultured from various food products.

2009 Publications

Nicolaescu, M., C. Savo, C.L. Hicks, M. Militard, G. Garriel, and V. Butean. 2008. Research Concerning Fluctuations of Free Fatty Acids and Acidity levels in Romanian Traditional Cheese Burduf, Associated Changes in Listeria spp. and Lactobacillus ssp. Populations During Ripening. 5th Synposium on Cheese Ripening. Bern Switzerland, 9-13 March 2008.
www.cheese2008.ch/download.phpfilename=Nicolaescu 1.pdf

Yokel, R. A., C. L. Hicks and R. L. Florence. 2008. Aluminum bioavailability from basic sodium aluminum phosphate, an approved food additive emulsifying agent, incorporated in cheese. J. Food Chem. Toxicol. 46: 2261-2266.