Vibratory motions are common to packaged products in the shipping and distribution environment. Using an MTS vibration table, low-fat plain yogurt (packaged in various shipping containers) was vibrated and then evaluated for phase separation (whey-off) during storage. Three types of damage were apparent: (a) slight or definite whey-off, (b) cracked or broken coagulum and (c) completely disrupted coagulum. After 10 d of storage, whey-off was quantitated. Slight and definite whey-off corresponded to 0.2 to 0.6% (wt/wt) and 0.6 to 1.8% (wt/wt), respectively. Most damage was observed in the top layers of vibrated stacks (10 high). Stretch overwrapping the shippers proved most effective in reducing syneresis, with less than 1% of the primary containers evaluated showing phase separation.
The rubratoxins, toxic metabolites elaborated by Penicillium rubrum and Penicillium purpurogenum , have long been implicated in livestock disease. Because of this and renewed interest in these metabolites, this review was prepared. The following topics are discussed: rubratoxin occurrence; animal and microbial toxicity; morphology; isolation, identification and analysis; physical and chemical properties; new analytical methodologies; biosynthesis and toxin synthesis under controlled conditions.
Prompted by numerous consumer inquiries and several reports in the literature, this survey was undertaken to monitor the composition of yogurt in the mid-Michigan market. Forty-seven samples representing six brands were analyzed. Mean values ± standard deviation for the content of protein (Kjeldahl), fat (Mojonnier) and total solids (Mojonnier), pH and net weights were measured. The data are presented by product category, i.e. low-fat flavored, low-fat plain, full-fat flavored, full-fat plain, and cumulated for all samples. Wide variations in chemical composition were observed between and within brands surveyed. Mean values for all flavored samples surveyed (N = 42) were 4.34% protein, 2.34% fat, 25.88% total solids and 4.01 pH. Corresponding values for all plain samples surveyed were 5.68, 2.86, 16.90 and 4.23, respectively. The data show that 25% of all samples analyzed were greater than 6.6% overweight while 10.6% of the yogurts surveyed weighed less than the declared container net weight. Caloric values for flavored yogurts ranged widely. Mean caloric values for flavored, low-fat and full-fat brands were 106 and 121 cal/100 g, respectively. In general, the results indicate that commercial yogurt would benefit from closer composition control.