Inhibition of Methyl Linoleate Peroxidation by Maize Zein in Powder Model System at High Water Activity.

Several samples of cheese obtained from regular retailers in Campinas, Brazil, were examined for molds and mycotoxins. Strains of Aspergillus and Penicillium were isolated and evaluated for their potential for producing toxins. Two of the isolated Penicillium species produced citrinin, while another produced patulin. However, no mycotoxins were detected in any of the cheese samples tested. Experiments with different types of cheese and a semisynthetic cheese were carried out in order to verify production of citrinin and patulin. It was observed that citrinin may be produced in cheese with high water activity and in semisynthetic cheese. However, patulin does not appear to be stable in cheese, even in semisynthetic cheese with high water activity and high carbohydrate contents.

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Review: Kinetic parameters for thiamine degradation in foods and model solutions of high water activity

International Journal of Food Science & Technology ◽

10.1111/j.1365-2621.1989.tb00613.x ◽

2007 ◽

Vol 24 (1) ◽

pp. 1-9 ◽

Cited By ~ 21

Author(s):

LILIANA M. MAURI ◽

STELLA M. ALZAMORA ◽

J. CHIRIFE ◽

MARÍA J. TOMIO

Keyword(s):

Kinetic Parameters ◽

Water Activity ◽

High Water ◽

Model Solutions

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Effects of vacuum and multiflash drying on the microbiota and colour of dried yellow mealworm (Tenebrio molitor)

Journal of Insects as Food and Feed ◽

10.3920/jiff2020.0170 ◽

2021 ◽

pp. 1-12

Author(s):

R.E.Y. Seho ◽

R.L. Monteiro ◽

J. De Dea Lindner ◽

M. Miotto ◽

B.A.M. Carciofi ◽

...

Keyword(s):

Water Activity ◽

Challenge Test ◽

High Water ◽

Tenebrio Molitor ◽

Microbial Reduction ◽

Microbial Load ◽

Vacuum Drying ◽

Drying Time ◽

Yellow Mealworm ◽

Food And Feed

Larvae of Tenebrio molitor (yellow mealworm; YM) are an alternative to conventional animal protein as food and feed thanks to their high nutritional value and low environmental impact for production. Since some studies have reported high water activity (aw) with different microbial contamination levels, blanching and drying can be employed to reduce microbial load, enzymatic activity, moisture content, and water activity, ensuring safety and preserving YM for longer periods. This study applied rinsing or blanching followed by vacuum- or multiflash drying, aiming to preserve YM by reducing aw and the microbial load, enabling its use as food and feed. The processing impact on YM colour was evaluated, and they were also subjected to an Escherichia coli contaminated wheat bran to perform a challenge test to evaluate the effectiveness of the decontamination. Drying curves were determined for each situation. Multiflash drying procedure was faster than vacuum drying for reducing YM moisture. Additionally, blanched samples required a shorter period to reach the targeted water activity (0.2-0.3) than rinsed samples. Blanching plus vacuum drying reduced more than 5 log E. coli load in YM in the challenge test. Vacuum drying preserved YM brightness the most. In conclusion, this study showed that drying could provide shelf-stable YM. Besides, only 15 s of blanching before drying gives better brightness and leads to a greater microbial reduction after a relatively short drying time.

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Fermentation Problem in Spanish North-Coast Honey

Journal of Food Protection ◽

10.4315/0362-028x-58.5.515 ◽

1995 ◽

Vol 58 (5) ◽

pp. 515-518 ◽

Cited By ~ 17

Author(s):

SUSANA SANZ ◽

GLORIA GRADILLAS ◽

FUENCISLA JIMENO ◽

CONSUELO PEREZ ◽

TERESA JUAN

Keyword(s):

Water Content ◽

Water Activity ◽

Microbiological Quality ◽

Free Water ◽

High Water ◽

North Coast ◽

High Water Content ◽

Free Water Content ◽

Cantabrian Coast ◽

Mold And Yeast

Twenty-one samples from the Cantabrian coast were analyzed to establish their microbiological quality and fermentation tendency. In a food with a very low free-water content like honey, microbiological growth is only possible when there is an increase in water activity. Since most of the samples studied were not extensively granulated, the risk of fermentation is mostly due to high water content. Among our samples, only two had a water content below 17.1% (no risk of fermentation), whereas the high water activity of the rest of the samples indicates the possibility of microbial growth. In fact, four of the samples analyzed showed a moisture content over the Spanish maximum legal limit, which means a high risk of fermentation. The absence of Enterobacteriaceae, coliforms, and Escherichia coli in our samples indicates an appropriate cleanliness during extractions and handling of honey. No Salmonella or Shigella were found. The relationship between water activity and mold and yeast counts found for the honeys analyzed allowed us to divide our samples in two groups: honeys with a high or a low risk of fermentation. Changes observed during storage of the samples confirmed this classification.

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Relationship Between Water Activity, Salts of Lactic Acid, and Growth of Listeria monocytogenes in a Meat Model System

Journal of Food Protection ◽

10.4315/0362-028x-55.8.574 ◽

1992 ◽

Vol 55 (8) ◽

pp. 574-578 ◽

Cited By ~ 74

Author(s):

NING CHEN ◽

LEORA A. SHELEF

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Moisture Content ◽

Water Activity ◽

Sodium Lactate ◽

Model System ◽

Cell Numbers ◽

Maximum Cell ◽

The Relationship ◽

Control Samples

The relationship between water activity (aw), lactate, and growth of Listeria monocytogenes strain Scott A was studied in a meat model system consisting of cooked strained beef ranging in moisture content from 25 to 85% (wt/wt). Lactate (4%) depressed meat aw, and differences between aw values in control and lactate-treated samples at each moisture level increased progressively with decrease in moisture, from 0.003 (85% moisture) to 0.046 (25% moisture). Maximum cell numbers per g in control samples stored at 20°C for 7 d were about 109 (45–85% moisture, aw= 0.981–0.994) and 107 (35% moisture, aw = 0.965); there was no growth in meat with 25% moisture (aw = 0.932). Sodium lactate (4%) suppressed listerial growth at >55% and inhibited growth in samples with 25–55% moisture (a < 0.964). Lactate concentrations less than 4% were not listeristatic, but combinations of 2 or 3% lactate with 2% NaCl in samples with 55% moisture inhibited growth. Potassium and calcium lactate were as effective as the sodium salt in suppressing growth and aw.

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Risks of Salmonellosis and Staphylococcal Food Poisoning From Pakistani Milk-based Confectioneries

Journal of Food Protection ◽

10.4315/0362-028x-55.8.588 ◽

1992 ◽

Vol 55 (8) ◽

pp. 588-594 ◽

Cited By ~ 10

Author(s):

PAUL TEUFEL ◽

FRANK L. BRYAN ◽

FAHMIDA QADAR ◽

SHAHID RIAZ ◽

SABIHA ROOHI ◽

...

Keyword(s):

Water Activity ◽

Food Poisoning ◽

High Water ◽

Foodborne Illness ◽

Milk Product ◽

Control Points ◽

Warm Environment ◽

Critical Control Points ◽

Retail Outlets ◽

Concentrated Milk

Hazards of milk-based products were conducted in three confectionery manufacturing shops in a city in Pakistan. The incoming khoa (a heat-concentrated milk product having a water activity of approximately 0.97) was initially contaminated with staphylococci and contained enterotoxin. The confectionery was subsequently cooked to temperatures that would be lethal to staphylococci, but staphylococci were often found in high numbers in the finished products. Recontamination occurred during handling. Khoa-filled confectionery and confectionery made from renin-processed cheese were contaminated by salmonellae. The contaminants reached the products either during cooling or handling after cooking. Multiplication occurred in the warm environment of the shop and may continue in products having high water activity during transport and within retail outlets. Critical control points are source of ingredients (particularly khoa), formulation, cooking (except for preformed enterotoxins), cooling, and cold storage. Milk-based products of the types evaluated pose a high risk of causing foodborne illness.

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