Electrostatic powder coating of sodium erythorbate and GDL to improve color and decrease microbial counts on meat Sheryl A. Barringer T , Jareer Abu-Ali, Hai-Jung Chung Department of Food Science and Technology, The Ohio State University, 100 Parker Food Science and Technology, 2015 Fyffe Rd, Columbus, OH 43210, USA Received 6 January 2004; accepted 4 January 2005 Abstract Powdered sodium erythorbate (SE) and a 3:1 mixture of glucono-delta-lactone and sodium erythorbate (GDL:SE) were coated electrostatically onto the surface of meats to extend the shelf life. The total number of microorganisms after refrigerated storage was reduced an average of 2 logs, with little difference by type of powder. Coliforms, mesophiles and psychrotrophs showed equivalent reductions. The color, as measured by the a value, was better for the treated samples than the control. GDL:SE samples were redder than SE. Electrostatic coating produced better results than nonelectrostatic coating due to the increased transfer efficiency of the process. Electrostatic coating also reduced the dust that is produced when powder is coated nonelectrostatically. D 2005 Elsevier Ltd. All rights reserved. Keywords: Electrostatic; Sodium erythorbate; GDL; Meat Industrial relevance: Sodium erythorbate and glucano-delta-lacton have been shown to extend the shelf life of meat products. This paper offers an interesting processing variable via electrostatic surface application of the powder. Electrostatic coating proved effective likely due to increased transfer efficiency and evenness of the process. 1. Introduction Processed meat products undergo deterioration from oxidative and microbial processes during storage. Oxymyo- globin oxidizes to metmyoglobin and gives a color change from bright red to unattractive brown, which limits the shelf life of meat. In a shopping market test, the redder the meat, the more likely consumers were to buy it (Hood & Riordan, 1973). Microbial growth of spoilage and pathogenic bacteria is another critical factor in quality deterioration of meat products. Both color and microbial deterioration in meat products are major concerns to meat producers and consumers. Sodium erythorbate has been shown in a number of studies to extend the shelf life of meat products. It helps to stabilize color in sausages and ground beef (Kovatscheva, Dantschev, Popova, Angelova, & Ivanova, 1987; Phillips, Mancini, Sun, Lynch, & Faustman, 2001). It increases color stability in turkey hams and turkey franks, possibly due to interaction with nitrite (Hasiak, Chaves, Sebranek, & Kraft, 1984; Wesley, Marion, & Sebranek, 1982). Its addition decreases microbial counts and maintains color in beef (Zuckerman & Mannhein, 2001) and it decreases the counts of Campylobacter jejuni in turkey meat (Juven, Kanner, Weisslowicz, & Harel, 1988). Glucono-delta-lactone (GDL) is another acidulant that has been used to extend the shelf life of meat. It has been used in bologna to inhibit growth of Listeria monocytogenes (Quist, Sehested, & Zeuthen, 1994). In a beef and pork product, it reduced total microbial counts (Farkas & Andrassy, 1993). Combined with lactate, it increases color and inhibits L. monocytogenes during storage (Juncher et al., 2002). A number of studies, as well as reports by the distributor, have shown a synergistic effect when GDL is combined with other acids. Mixed with sodium erythorbate, GDL inhibits the growth of Bacillus cereus in liver sausage better than sodium erythorbate alone (Asplund, Nurmi, Hill, & Hirn, 1988). 1466-8564/$ - see front matter D 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.ifset.2005.01.003 T Corresponding author. Tel.: +1 614 688 3642; fax: +1 614 292 0218. E-mail address: barringer.11@osu.edu (S.A. Barringer). Innovative Food Science and Emerging Technologies 6 (2005) 189– 193 www.elsevier.com/locate/ifset