Effect of Carbon Dioxide on the Growth of Bacillus cereus Spores in Milk During Storage

• Published in: Journal of dairy science Vol. 85; no. 1; pp. 15 - 18
• Main Authors: Werner, B.G., Hotchkiss, J.H.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.01.2002; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: Animals; Bacillus cereus - drug effects; Bacillus cereus - growth & development; Bacillus cereus spores, milk, carbon dioxide, shelf-life extension; Biological and medical sciences; Carbon Dioxide - pharmacology; Cattle; Colony Count, Microbial; Food Handling; Food industries; Food Microbiology; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Linear Models; Milk - chemistry; Milk - drug effects; Milk - microbiology; Milk and cheese industries. Ice creams; Spores, Bacterial - drug effects; Spores, Bacterial - growth & development; Time Factors; Bacillus cereus spores, milk, carbon dioxide, shelf-life extension; SPC; Microorganism growth; Bacillus cereus; Bacillales; Carbon dioxide; Dairy product; Bacteria; Stored food product; Bacillaceae; Milk
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(02)74047-2

The effects of the addition of 11.9mM CO2 on the growth of Bacillus cereus spores inoculated into sterile homogenized whole milk at 101 and 106 spores/ml and stored at 6.1°C, was examined weekly for 35 d. Colony-forming units from CO2 treated inoculated milks decreased over 35 d at a rate similar to that of untreated inoculated milk, as defined by linear regression. Plate counts for treated and control milks inoculated at 101 cfu/ml were not significantly different on sampling d 0, 14, 21, and 28. Plate counts at d 7 were significantly different and counts at d 35 were at undetectable levels for both treated and control milks. Plate counts for milk inoculated at 106 cfu/ml were not significantly different on d 0, 28, and 35; they were significantly different on d 7, 14, and 21. There was no consistency as to whether the control or test milks were higher in counts on days when the differences were significant. Added CO2 reduced the pH of the milk from an average value of 6.61 to an average value of 6.31; however, this drop did not correlate with changes in any other parameter measured. These data suggest that moderate levels of CO2 do not enhance the outgrowth of B. cereus spores over long-term storage and do not increase the risk of foodborne illness due to the organism.