Toxin Production by Clostridium botulinum in Pasteurized Milk Treated with Carbon Dioxide

Abstract

The addition of carbon dioxide to milk at levels of <20 mM inhibits the growth of selected spoilage organisms and extends refrigerated shelf life. Our objective was to determine if the addition of CO2 influenced the risk of botulism from milk. Carbon dioxide was added to pasteurized 2% fat milk at approximately 0, 9.1, or 18.2 mM using a commercial gas-injection system. The milk was inoculated with a 10-strain mixture of proteolytic and nonproteolytic Clostridium botulinum spore strains to yield 10(1) to 10(2) spores/ml. Milk was stored at 6.1 or 21 degrees C for 60 or 6 days, respectively, in sealed glass jars or high-density polyethylene plastic bottles. Milk stored at 21 degrees C curdled and exhibited a yogurt-like odor at 2 days and was putrid at 4 days. Botulinal toxin was detected in 9.1 mM CO2 milk at 4 days and in all treatments after 6 days of storage at 21 degrees C. All toxic samples were grossly spoiled based on sensory evaluation at the time toxin was detected. Although botulinal toxin appeared earlier in milk treated with 9.1 mM CO2 compared to both the 18.2 mM and untreated milk, gross spoilage would act as a deterrent to consumption of toxic milk. No botulinal toxin was detected in any treatment stored at 6.1 degrees C for 60 days. At 6.1 degrees C, the standard plate counts (SPCs) were generally lower in the CO2-treated samples than in controls, with 18.2 mM CO2 milk having the lowest SPC. These data indicate that the low-level addition of CO2 retards spoilage of pasteurized milk at refrigeration temperatures and does not increase the risk of botulism from treated milk stored at refrigeration or abuse temperatures.

The use of carbon dioxide in the processing and packaging of milk and dairy products: A review

“…Werner and Hotchkiss (2002) advocated that the addition of moderate levels of CO 2 (11.9 mM) did not have either stimulatory or inhibitory effect on the initiation of germination and subsequent outgrowth of B. cereus spores over long‐term storage and did not increase the risk of food borne illness. Similar conclusions were made regarding C. botulinum (Glass et al. 1999).…”

Addition of Carbon Dioxide to Dairy Products to Improve Quality: A Comprehensive Review

“…We have investigated the effect of added CO 2 on B. cereus and C. botulinum growth and toxigenesis in milk (Glass and others 1999; Werner and Hotchkiss 2002). While CO 2 at levels of <20 mM inhibits the growth of selected spoilage organisms and extends refrigerated shelf life, CO 2 could influence the risk of botulism from milk.…”

“…While CO 2 at levels of <20 mM inhibits the growth of selected spoilage organisms and extends refrigerated shelf life, CO 2 could influence the risk of botulism from milk. In the latter study (Glass and others 1999), pasteurized 2% fat milk was modified with approximately 0, 9.1, or 18.2 mM CO 2 and inoculated with a 10‐strain mixture of proteolytic and nonproteolytic C. botulinum spore strains to yield 10 1 to 10 2 spores mL ‐1 . The milk was stored at 6.1 °C for 60 d or 21 °C for 6 d in sealed glass jars or high‐density polyethylene (HDPE) plastic bottles.…”

Culture-independent bacterial community profiling of carbon dioxide treated raw milk

“…Studies to date on the effect of CO 2 on the growth of Listeria monocytogenes, Bacillus cereus and Clostridium sporogenes in milk or cottage cheese and toxingenesis of Clostridium botulinum in milk have shown that CO 2 treatment does not pose increased risk with regard to these factors (Chen and Hotchkiss, 1993;Glass et al, 1999;Werner and Hotchkiss, 2002). In addition, culture-independent studies on the native bacterial composition of carbonated raw milk during cold storage have found no evidence of selection of harmful bacteria (Rasolofo et al, 2011;Rasolofo et al, 2010).…”