Combined Effect of Modified Atmosphere Packaging and Low-Dose Irradiation on Toxin Production by Clostridium botulinum in Fresh Pork

Abstract

The combined effect of three initial levels of oxygen (0, 10, and 20%), irradiation dose (0, 0.5, and 1 kGy), and storage temperature (5, 15, and 25°C) on toxin production by Clostridium botulinum in inoculated modified atmosphere packaged pork were investigated using factorial design experiments. Toxin was detected after only 2 d in all treatments stored at 25°C. At 15°C, irradiated and nonirradiated product packaged with 10 or 20% headspace oxygen were toxic after 14 d. For product packaged with 0% oxygen and an oxygen absorbent, toxin was detected after 21 d in nonirradiated samples compared to 43 d for product treated with an irradiation dose of 1 kGy. No toxin was detected in any product stored at 5°C, even after 44 d. Headspace oxygen in product initially packaged with 20% oxygen decreased to 0.1% after 14 d at 15°C and to ≤3% after 5 d at 25°C, with a concomitant increase in package headspace CO2 to 25–40%. For product packaged with 0% O2 and an oxygen absorbent, oxygen remained at ≤2% throughout the storage trial, while CO2 increased to 10 and 24% for nonirradiated and irradiated samples, respectively. Initial packaging of product with O2 appeared to enhance toxin production by C. botulinum in product stored at 15°C, probably as a result of increased CO2 enhancing spore germination.

Mathematical modeling, non-destructive analysis and a gas chromatographic method for headspace oxygen measurement of modified atmosphere packaged soy bread

“…Thus, the greater the microbial counts, the quicker the oxygen consumption within the headspace of the package. Our results are similar to those obtained by Lambert et al (1991) who reported that oxygen decreased more slowly within packaged pork samples subjected to a preservation technique when compared to those not subjected to the preservation technique.…”

Bacteriological Quality of Imported Frozen Chicken in Sulaimani Markets

“…Even though, both Tyson and AJC marks were unpackaged at retail selling. The effect of freezing on the microorganisms may be the major reason for lowering coagulase positive staphylococcal count (Lambert et al, 1991 andJay et al, 2005). In a similar study, Al-Hamadany (2009) mentioned that the mean count of Staphylococcus aureus in Sadia mark thighs was zero CFU/ g meat in whole sells, and 1×10 2 CFU/g meat in retail sells.…”

Effects of Carbon Dioxide on Growth of ProteolyticClostridium botulinum, Its Ability To Produce Neurotoxin, and Its Transcriptome

“…(5,13,15,20). Previous studies using proteolytic C. botulinum reported a delay in neurotoxin formation with headspace con- centrations in excess of 45% CO 2 (11,12,17,18), although a further report indicated that neurotoxin formation was unaffected by sparging with 100% CO 2 (30). This apparent inconsistency probably reflects differences in experimental design.…”