Cameron's Putrefactive Anaerobe 3679 is widely used as a test organism to evaluate process requirements f o r low-acid canned foods. Although the thermal resistance of this organism is known to vary with the substrate in which it is heated (2, 15, 18), until recently (10, 16) there were relatively few data in the literature that defined the constants of thermaldeath-time curves of the organism in vegetable substrates. Most of these data specify the resistance of spores when heated in liquid extracts or purCed vegetables. Townsend, Esty, and Baselt (18) have emphasized the need f o r information based on work with raw products rather than with brines from processed foods, and data reported more recently by Reed, Bohrer, and Cameron (10) indicate that heat resistance of spores in a given vegetable substrate may cliff e r considerably, depending on whether the substrate is prepared as a pt1ri.e or as larger piwrs sixspended in brine.With respect to processes f o r nonpurked vegetables, it seems reasonable to assume that the latter medium would be superior to the p r 4 e in providing environmental conditions that simulate conditioiis to which spores are exposed in containers of vegetables during processing.The study reported in this article, was undertaken to augment currently available data by determining the constants of thermal-death-time curves of P. A. 3679 spores heated in 13 low-and medium-acid vegetables, chopped or cut.Terms and nomenclature used in this paper are coiisistent with those used by Ball ( 3 ) , Townsend, Esty, and Baselt (18), Sognefest and Benjamin ( 1 4 ) , Reed, Bohrer, and Cameron (ZO), and others. E X P E R I M E N T A L METHODSPreparation of spore suspensions. Spore suspensions of P. A. 3679 were prepared by culturing the organism in 10% egg-meat medium (Difco) a t 3OoC.(86"F.) f o r 3 weeks, filtering the medium through glass wool, centrifuging the filtrate, and suspending the spores in a small volume of sterile 0.5% peptone solution. Concentrated suspensions, containing 3 X lo8 to 3 X lo8 spores per ml., were distributed in 2 t o 4 ml. quantities in TDT (thermal-death-time) tnhes. The tubes were sealed and heated for 20 minutes at 1OO0C.(212"P.) (12) and held under refrigeration until used.Preparation of substrates. Both commercially frozen and fresh food samples were used for preparing food substrates. Frozen foods were thawed; fresh vegetables were washed, trimmed, and blanched. All samples, with the exception of asparagus and spinach, were chopped in a hand food chopperb. Asparagus and spinach were chopped

One of the most common abnormalities associated with olives pickled in California is known throughout the industry as "yeast spots." This blemish, shown in figure 1, is characterized by the formation of raised white spots or pimples between the inner surface of the skin and the flesh of the olive. Although in general, the Sevillano variety most frequently shows this blemish, the spots may be found on all varieties and types of olives which have undergone fermentation in salt brines.' Because such olives are considered unsightly, some loss of value of the pickled fruit may be experienced, although the olives may be perfectly normal and healthful in other respects.These small white spots actually are colonies of microorganisms which have developed during the fermentation. Vaughn, Douglas and Gililland (1943) reported that most of the pimples examined in the laboratory contained lactobacilli, some cultures of which were identified as Lactobacillue plantarum. Then a deliberate search for yeasts was initiated because general use of the term "yeast spots" indicated that yeasts actually had been observed in the pimpled olives. No yeasts were found. After it was apparent that most, if not all, of the spots contained bacteria, it was decided to determine the predominating types. These investigations are described in the following pages. EXPERIMENTAL METHODS SamplesCalifornia olives collected for examination included Spanish type green olives, Sicilian type green olives, brined Greek type olives, storage fruit held in brines for subsequent preparation of ripe olives, and canned ripe olives. Authentic samples of Spanish green olives also were obtained.An individual sample consisted of at least 10 spotted olives. Between 1942 and 1952, 115 different samples were examined. These included 40 Spanish type, 25Sicilian type, 5 brined Greek type, 30 brined storage, 5 canned ripe and 10 authentic Spanish olive samples. Microscopic ExaminationTo determine whether bacteria or other microbes were present, the contents of at least 10 spots on each

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