Infectivity of Trichinella spiralis from Frozen Pork

Abstract

This research was carried out to determine the time/temperature exposure of Trichinella spiralis to freezing conditions necessary to destroy the infectivity of the trichinae. Experimentally infected pork was subjected to temperatures of −1 to −193°C for one sec to 182 d and the treated pork samples, which contained about 1000 larvae per gram of tissue, were subjected to rat bioassay to determine infectivity of the larvae. A linear regression equation, log10t = 5.98 + 0.40T where t = required inactivation time in hours and T = temperature in degrees Celsius, described the exposure necessary to destroy the trichinae. The correlation for that relationship was r = 0.942. The predicted thermal death times (+7 min) at −20, −15, and −10°C were 8 min, 64 min, and 4.0 d, respectively. The predicted upper confidence limits (99%) for the thermal death times (+7 min) for exposure at −20, −15, and − 10°C, were 48 min, 63 h, and 266 d, respectively. These data provide a continuum of definitive times and temperatures necessary to destroy T. spiralis by freezing and are of value to the meat industry and the regulatory agencies.

Infectivity, predilection sites, and freeze tolerance of Trichinella spp. in experimentally infected sheep

“…These ®ndings suggest that T. spiralis and T. pseudospiralis can potentially infect humans from fresh and frozen sheep-meat products. It is noteworthy that the freeze tolerance of T. spiralis is obviously higher in sheep meat than in pig meat, where larvae are killed within a matter of days (Kotula et al 1990). This aspect should be further evaluated in other animals, including other herbivorous hosts such as goats and horses.…”

Microbial growth and its control in meat, poultry and fish

“…and Echinococcus spp. (Fayer and Dubey, 1985;Greiner, 1989; Jackson, 1990; Kotula et al, 1990Kotula et al, , 1991. Fish also may harbor various parasites most of which are harmless to humans and include Clororchis (Opisthorchis) spp., Heterophyes heterophyes, Diphyllobothrium spp., Metagominus yokogawai, Gnathostoma spinigerum, Capillaria philippinensis, Anisakis simplex and Plocanema spp.…”

Effect of Some Physical Factors on the Viability of Third-Stage Gnathostoma binucleatum Larvae

“…to protect the fish consumer's health. Freezing has also been sbown to be effective in killing larvae of Trichinclla spiralis in pork and Taenia saqinata in beef (8,10).…”

“…Finding a larvae-inactivation method to that can be applied to all fish before being consumed would reduce the risk of acquiring the disease. Treatment with certain physical factors such as gamma radiation and thermal treatment (freezing and boiling) has been found to inactivate some helminthes (7,10,16).…”