FURTHER STUDIES ON THE EFFECT OF EXPERIMENTALLY INOCULATING CANNED BREAD WITH SPORES OF CLOSTRIDIUM BOTULINUM^a,b

Abstract

From the data obtained in previous experiments designed to test the safety of canned bread ( 3 ) , military specifications for p H and moisture were written for this product ; namely, that the p H of the crumb shall not exceed 4.8 and the total moisture content of the finished bread shall not exceed 33%. These specifications were assumed to be readily obtainable by commercial bakers in producing canned bread f o r the Armed Forces. The desired pH level was attained by adding the proper quantity of edible lactic acid to the sponge water. Bakers in some instances, however, encountered difficulty in staying below the allowable maximum moisture level. I n the present study experiments were designed to test the safety of canned bread from the botulism hazard at several moisture levels above the maximum stated in the Specifications. Spores of the same six strains of Clostridizrm botzdinzcm (three each of types A and B) tested previously were used as the inoculum. I n addition several iininoculated control cans were included with each experimental series. One half of the canned bread was adjusted with edible lactic acid to have a final pII near 4.8. The other half was adjusted with sodium hydroxide solution t o yield a final p H near 5.8. The moisture levels aimed at in the baked product were 34, 36, 38, and 40%. The actual levels, as determined by analysis, were somewhat different and moisture variations were ellcountered among samples baked from similar doughs.The experiments reported in this investigation were carried out in cooperation with the staff of the Quartermaster Food and Container Institute f o r the Armed Forces.

Shelf Life and Safety Concerns of Bakery Products—A Review

“…Growth and toxin production was observed in inoculated canned bread with a pH of 5.8 and a moisture content >36% and in canned steamed chocolate nut bread with a pH of 6.8 and 36% moisture. 255,256 Bread with a pH of 4.8 was determined to be safe, as no growth occurred, and the number of inoculated spores decreased during ambient storage in an erh of 97%. 127 However, the safety of the bread depended on maintaining its pH throughout storage, as there were still viable spores after six months.…”

STUDIES ON CANNED CHOCOLATE NUT ROLL EXPERIMENTALLY INOCULATED WITH SPORES OF CLOSTRIDIUM BOTULINUM TYPES A AND Ba,b

“…Data obtained in previous experiments designed to test the safety of canned bread (3) showed that with bread initially adjusted to pH levels near 4.8 no toxin was produced in simples inoculated with C. botulinurn even at moisture levels near 4@%. In similar bread initially adjusted to approximately pH 5.8 toxin was produced after 12 months of storage at 90" F in all samples with moisture levels above 36%.…”

Cereals and cereal products

“…This a w is equivalent to a moisture content of about 40%. As long as the water content did not exceed 36%, no toxin was formed (Wagenaar and Dack, 1954;Denny et al, 1969). There have been no reports of botulism from this product.…”

“…Acid breads, whose pH is ≤4.8, are safe from botulism, even when the moisture content is 40% (Wagenaar and Dack, 1954;Ingram and Handford, 1957;Weckel et al, 1964).…”