Effect of temperature, anaerobiosis, stirring and salt addition on natural fermentation silage of sardine and sardine wastes in sugarcane molasses.

Conditions for a natural fermentation during ensilage of sardines or their waste in sugarcane molasses (60:40 w/w) were evaluated regarding the effect of temperature (15, 25 and 35 degrees C), anaerobiosis (closed vs. open jars), daily stirring of the mixture, and salt addition to the initial mix at 5% (w/w) level. Successful natural fermentation took place in sardine silages incubated at 25 or 35 degrees C in open jars to reach a pH of 4.4 in about 2 and 1 weeks, respectively. For samples kept at 15 degrees C, the pH decline was very slow and pH did not decrease below 5.5 after one month of incubation. At 25 degrees C, the most favorable conditions for silage of sardine waste in cane molasses, as evidenced by the fastest decline in pH to a stable value of about 4.4, were achieved in closed jars and with daily stirring of the mix. The pH 4.4 was reached in one week with an advance of at least 3 days compared to the other conditions (open jars and closed jars without daily stirring). Addition of salt at 5% (w/w) in the mix before incubation inhibited the fermentation process.

A mathematical model for the flotation of waste activated sludge.

A mathematical model that describes a batch flotation process is presented. The model employed a similar method to the hindered settling of flocculated material. This idea is based on our experimental results that the time growth curves of separated liquor zone showed a similar character to the settling curve of flocculated material, when the vertical axis reversed. In this model, it is also assumed that the gas phase and solid phase have the same movement, that is microbubbles and solid sludge particles joined to form aggregated floc. By comparing the numerical prediction with experimental data, the usefulness of the model is confirmed and some examples of flotation simulation are demonstrated.

Isolation of a bacteriocin-producing Lactococcus lactis subsp. lactis and application to control Listeria monocytogenes in Moroccan jben.

AIM: Use of a bacteriocin-producing lactococcal strain to control Listeria monocytogenes in jben. METHODS AND RESULTS: A Lactococcus lactis strain isolated from lben was shown, by the spot technique, to produce a bacteriocin different from nisin. Inhibitory activity of the bacteriocin-producing strain against Listeria monocytogenes was investigated in jben, made from cow's milk fermented with the producer organism and contaminated with 104 or 107 cfu ml-1. Listeria counts were monitored during manufacture, and during conservation at room and at refrigeration temperatures. Results showed that the pathogen was reduced by 2.7 logarithmic units after 30 h of jben processing when the initial inoculum of 107 cfu ml(-1) was used. For the initial inoculum of 104 cfu ml(-1), the bacterium was completely eliminated at 24 h. Furthermore, the use of the bacteriocin-producing starter culture extended the shelf-life of jben by 5 days. CONCLUSIONS: In situ production of the lactococcal bacteriocin is an efficient biological means of controlling L. monocytogenes in jben and of allowing shelf-life extension. SIGNIFICANCE AND IMPACT OF THE STUDY: The proposed technology will essentially benefit minimally processed dairy products and those made with raw milk.

Vitamin A distribution among fat globule core, fat globule membrane, and serum fraction in milk.

In cream suspensions and partly skimmed milks obtained by successive centrifugation from whole milk, the concentration of vitamin A per gram of fat was inversely related to the mean size of fat globules. This result indicated that not all the vitamin A of milk was located in the fat globule core, which was further supported by studies of buttermilk and butter oil fractions obtained by churning of cream. These studies indicated that a portion of the vitamin A was associated with the fat globule membrane. The vitamin A content per gram of fat of purified fat globules was similar to vitamin A content per gram of fat of the whole milk from which they were isolated. This result indicated that the amount of vitamin A in the serum fraction was negligible and that vitamin A was localized in the fat globule and fat globule membrane.

Factors related to the light stability of vitamin A in various carriers.

Skim milk fortified with all-trans retinyl palmitate, using corn or coconut oil as the vitamin carrier, was studied to determine the effect of physical state and droplet size of the carrier system on loss of all-trans retinyl palmitate during exposure to light. To determine effect of physical state, fortified samples were exposed to light at 4 degrees C, where corn oil is liquid and coconut oil solid, or 35 degrees C where both oils are liquid. At 4 degrees C, rates of light degradation of all-trans retinyl palmitate in corn or coconut oil were significantly different from each other; at 35 degrees C they were not. Different droplet sizes of the carrier systems were achieved by homogenizing skim milk at different pressures (169, 105, or 35 kg/cm2). In all cases, greater loss occurred in corn oil as the vitamin carrier compared to coconut oil. Degradation rate of all-trans retinyl palmitate increased with decreased homogenization pressure. Effects of photooxidation of fatty acids on degradation of all-trans retinyl palmitate and isomerization of retinyl palmitate were investigated in four carrier systems (corn, butter, peanut, and coconut) by exposing the fortified oils to light. Peroxide values did not parallel degradation of all-trans retinyl palmitate during light exposure. Isomerization of all-trans to cis isomers of retinyl palmitate occurred in all carrier systems.

Photochemotherapy of psoriasis using methoxsalen and sunlight. A controlled study.

Fifty-one patients with psoriasis were treated with oral methoxsalen and sunlight exposure. Twelve of these patients received either methoxsalen or placebo prior to whole-body exposure. The remainder were treated with methoxsalen and sunlight to one side of the body and sunlight alone to the other. The conventional dose of methoxsalen (0.6 mg/kg) was compared with a low dose (0.3 mg/kg). Oral methoxsalen when used in the higher dose followed by sun exposure is an effective treatment for psoriasis. Accurate ultraviolet dosimetry is essential to avoid phototoxic burns. The advantages and disadvantages of solar photochemotherapy are discussed.