Factors associated with the serological prevalence of Salmonella enterica in Greek finishing swineherds.

Blood samples were taken from 50 finishing pigs at 90-105 kg in each of 59 randomly selected farrow-to-finish herds. The sera were tested for antibodies to Salmonella enterica by the Danish mix-ELISA. Samples with an optical density of > 10% were considered to be positive.

Seroprevalence and antibiotic sensitivity of serotypes of Salmonella enterica in Greek pig herds.

Blood samples were taken from 50 pigs in each of 59 farrow-to-finish production herds and from 40 pigs in each of four of five registered multiplying herds. Samples of feed and faeces were also collected from 17 of the production herds and from the four multiplying herds. The sera were tested for antibodies to Salmonella enterica by the Danish mix-ELISA, and the organisms were isolated, serotyped and sensitivity tested by standard techniques.

Prediction of Listeria spp. growth as affected by various levels of chemicals, pH, temperature and storage time in a model broth.

The effects of concentration of NaCl (0.5 to 12.5%), methyl paraben (0.

Temperature distribution and prevalence of Listeria spp. in domestic, retail and industrial refrigerators in Greece.

The present paper examined the presence of Listeria spp. in the environment of domestic, retail and industrial refrigerators. From 136 household refrigerators, 136 surface samples were taken from the walls or shelves, and 125 from cheese compartments.

Potential growth and control of Escherichia coli O157:H7 in soft hispanic type cheese.

This study examined growth and control of two enterohemorrhagic Escherichia coli serotype O157:H7 strains in a soft Hispanic type cheese (Queso Fresco). Cheese was made in the laboratory using a commercial procedure and after inoculation it was stored under vacuum at temperatures ranging from 8 to 30 degrees C. The minimum temperature that allowed growth of E.

Potential growth and control of Salmonella in Hispanic type soft cheese.

This study evaluated the growth and control of Salmonella serotypes in a soft Hispanic type cheese (Queso Fresco). Cheese was made in the laboratory using a commercial procedure and after inoculation it was stored under vacuum at temperatures ranging from 6 to 30 degrees C. The minimum temperature that allowed growth of Salmonella was 8 degrees C.

Modeling lag phase of nonproteolytic Clostridium botulinum toxigenesis in cooked turkey and chicken breast as affected by temperature, sodium lactate, sodium chloride and spore inoculum.

The length of the lag phase (LP) of toxigenesis in commercially cooked turkey meat stored under vacuum was determined as affected by 0, 1.2, 2 and 3% sodium lactate (L), 0, 1 and 2% NaCl (S), spore (pool of nonproteolytic B and E strains: B2, B17, B197, B706, E211, E250, E KA-2 and E Beluga) inoculum (I) of 10(-2) to 10(4), storage temperature (T) of 4, 8, 12, 16, 20 and 30 degrees C and their interactions. The time from inoculation to the detection of first toxic sample was defined as LP.

Disease determinants of sporadic salmonellosis in four northern California counties. A case-control study of older children and adults.

A population-based, case-control study of sporadic salmonellosis was conducted in 1988 and 1989 in four northern California counties. The study included 120 patients and 265 control subjects. Conditional logistic regression analysis (adjusted for age) revealed that patients were more likely to consume undercooked chicken prior to the onset of disease (odds ratio [OR], 23.

The Relationship Between Botulinal Toxin Production and Spoilage of Fresh Tomatoes Held at 13 and 23°C Under Passively Modified and Controlled Atmospheres and Air.

The formation of botulinal toxin relative to spoilage of fresh whole tomatoes was investigated at 13 and 23°C under passively modified (MA) and controlled atmospheres (CA) and air. Tomatoes were subsurface inoculated with a composite of type A and proteolytic and nonproteolytic type B strains of Clostridium botulinum spores. Some were also inoculated with Alternaria mold spores.

Interactive Effect of Temperature, Atmosphere and Storage Time on the Probability of Colony Formation on Blood Agar by Four Listeria Species.

The probability (P) of one Listeria cell and the cells needed to initiate colony formation on sheep blood agar plates as affected by atmospheric conditions (AC), storage temperature (T), time (t), and Listeria species was evaluated. The factorial design experiments included Listeria monocytogenes (2 strains), Listeria seeligeri , Listeria ivanovii , and Listeria innocua , as test organisms, storage of the plates at 4, 8, 20, and 30°C under air (A), modified atmosphere (MA) of 5% O, + 10% CO + 85% N, 100% CO (CO), vacuum (V), and candle jar (CJ) for 7, 14, 21, 42, and 56 d. Statistical analysis indicated the significant effect of AC (p<0.

Growth and Survival of Listeria monocytogenes in Market Cheeses Stored at 4 to 30°C.

Forty-nine market cheeses representing 24 types and 28 brands were purchased from local supermarkets. Pieces of cheeses of approximately 1.5 × 0.

Selected Microbiological and Chemical Characteristics of Illegally Produced and Marketed Soft Hispanic-Style Cheeses in California.

Recently, there has been a great concern among California state health authorities and the dairy industry that large volumes of illegally produced Hispanic-style cheeses find their way into local markets. In cooperation with the State Milk and Dairy Foods Control Branch, California Department of Agriculture, 100 samples of soft Hispanic-style cheese were collected from all over the state by undercover agents during seizures by state authorities. The cheeses were analyzed in our laboratory for aerobic plate counts, the presence of Salmonella and Listeria , pH, moisture, and salt (%).

Growth and toxigenesis of C. botulinum type E in fishes packaged under modified atmospheres.

Modified atmosphere packaging of fresh fish is used to market high quality products in some European countries. The potential risk of C. botulinum growth in these extended shelf-life foods is still a concern; especially since toxigenesis may precede organoleptic spoilage.

Prevalence of Listeria spp. in Turkey Meat at the Supermarket and Slaughterhouse Level.

The prevalence of Listeria spp. in the skins of turkey wings, legs (drumsticks), and tails was studied first. During three trips to local supermarkets we purchased and analyzed 180 packages representing two national brands.

Predicting the Safe Storage of Fresh Fish Under Modified Atmospheres with Respect to Clostridium botulinum Toxigenesis by Modeling Length of the Lag Phase of Growth.

The toxigenesis of non-proteolytic C. botulinum , types B, E, and F, in a variety of fresh fish stored between 4 and 30°C for up to 60 days was evaluated in a five year study. Muscle homogenates and fillets were inoculated with 10-10 spores from multiple strain pools, then modified atmosphere (MA) packaged under vacuum, 100% CO, or 70% CO and 30% N.

Present state of knowledge on staphylococcal intoxication.

Globally, staphylococcal intoxication remains a very common food poisoning. In this review, emphasis is being placed on epidemiological aspects of the problem and the effect of food environment on the survival and growth of staphylococci and production of enterotoxins. The high prevalence of staphylococci in raw foods of animal origin requires effective processing for safety.

Prevalence of Listeria spp. in Poultry Meat at the Supermarket and Slaughterhouse Level.

The prevalence of Listeria spp. in the skins of poultry legs (drumsticks), wings, and whole livers, representing 160 packages, three national brands, and purchased from three supermarkets in Davis, California was investigated first. Overall, Listeria spp.

Quantitative Evaluation of Clostridium botulinum Nonproteolytic Types B, E, and F Growth Risk in Fresh Salmon Tissue Homogenates Stored under Modified Atmospheres.

The potential risk of C. botulinum growth in fresh fish stored under modified atmospheres (MA) remains unclear, as few qualitative studies have identified certain conditions leading to toxigenesis. This is the second paper of a series attempting to quantify the effect of selected parameters on the probability (P) of toxigenesis by one spore in fish.

Origin and Prevalence of Campylobacter jejuni in Ducks and Duck Meat at the Farm and Processing Plant Level.

The epidemiology of Campylobacter jejuni colonization in poultry at the farm remains unclear. In this study, over a 6-month period, we evaluated the prevalence and possible ways of transmission of C. jejuni in a duck farm and a processing plant, belonging to the same company.

Risk of Growth and Toxin Production by Clostridium botulinum Nonproteolytic Types B, E, and F in Salmon Fillets Stored Under Modified Atmospheres at Low and Abused Temperatures.

In factorial design experiments we inoculated fresh salmon fillets with a spore pool of 13 nonproteolytic strains of Clostridium botulinum type B, E, and F at 6 levels (10 to 10/50 g of fillet), and incubated at 1, 4, 8, 12 and 30°C under modified atmospheres (MA) of vacuum, 100% CO and 70% CO + 30% air for up to 60 d. The earliest time we detected toxin in the fillets at 30, 12 and 8°C, irrespective of MA, was after 1, 3-9 and 6-12 d of storage and required 10-10, 10-10, 10-10 spores/fillet. The probability (P) of toxin production was significantly (P<0.

Campylobacter jejuni Infection on Poultry Farms and its Effect on Poultry Meat Contamination during Slaughtering.

In 1984, we monitored 4 ranches with a total of 24 houses (15,000-20,000 birds/house) for 3 consecutive generations (January-August). On epidemiologic grounds, infection of birds did not originate at the hatcheries or the central water and feed. Considering all lots of birds, the infection rate increased from 2.

Adaption of ELISA for the detection of Campylobacter antibodies and its application in seroepidemiological studies in sheep and cattle herds.

ELISA was adapted for the study of antigenic relations among important Campylobacters and for the presence of anti-campylo-bacter antibodies in 394 sheep and 265 cattle. Rabbit anti-C. jejuni, C.

Preliminary Observations on the Occurrence of Campylobacter jejuni at Four California Chicken Ranches.

During a 3-month period from April to July, 1983, three Campylobacter jejuni survey studies were done at four chicken ranches in Northern California. In Survey 1, 29 of 200 (14.5%) total cloacal swab and dropping samples collected from the 20 occupied houses on the four ranches were positive for C.

Use of enzyme linked immunosorbent assay (ELISA) in the quantitation of Clostridium perfringens type A enterotoxin and antienterotoxin antibodies.

ELISA procedure for quantitation of enterotoxin of Clostridium perfringens type A was worked out. It was possible to detect as little as 0.0022 microgramme of enterotoxin.

Prevalence of Campylobacter jejuni at Different Sampling Sites in Two California Turkey Processing Plants.

A prevalence survey for Campylobaeter jejuni from 12 sites was made in two turkey processing plants. Both plants are federally inspected but differ in the age of birds slaughtered (18 and 24 wk for plant A and B, respectively) and scald water temperatures (2.5 min at 60°C and 3 min at 57.